The TARDIS lands in a barren, muddy field. Jamie is first out, ankle deep in muck, followed by the others. Their joy at seeing a new place dissipates quickly in the grimness of the landscape. It is all barren, all muddy as far as the eye can see. It looks like Earth, but the Doctor wants to look around a bit more before deciding.

He leads the way up a steep, scrubby slope, passing some barbed wire strung out along it. Jamie has never seen such a thing and examines it, pricking his finger. The Doctor denounces it as "filthy stuff". His attention is drawn by something lying in the dirt - some battered clothing and a metal helmet. He recognises it instantly. They have landed in one of the most terrible times in the history of Earth. Before he can explain further, there is a whistling in the air and a bomb goes off very nearby. Soon, the atmosphere erupts in a full-scale artillery barrage.

The Doctor, Jamie, and Zoe take cover in a hole - actually a bomb crater - to wait out the seemingly endless barrage of bombs and bullets. When it ends, the silence is oppressive. It is broken by a kind female voice. A woman in military uniform and bearing a red cross on her sleeve beckons the three frightened civilians out of the crater. That, she says, was just a softening-up barrage. There will be more to come.

She tells the civilians that they are "between the lines", not a fit place for anyone really. She seems somewhat vague on the details, as if she herself can't quite remember where she is or where she's going. She turns to point to the ambulance she was driving when she is startled by two German soldiers in gas masks standing right behind her. Both are armed with rifles and they take all four people prisoner.

The Doctor, Jamie, and Zoe are forced into the back of the ambulance with one soldier whilst the woman, a WVR named Lady Jennifer Buckingham, is forced to drive. However, a short time later, the ambulance is stopped by 3 British soldier, a lieutenant, disarms the guard on Lady Jennifer and then goes to the back at her urging. The lieutenant finds no problems there - the Doctor, Jamie, and Zoe have disarmed and subdued their guard easily. The two British soldiers climb in with the prisoners and the civilians whilst the lieutenant, Carstairs by name, joins Lady Jennifer. He is as stunned as she is to have found three civilians in the no-man's land between the German and British lines. They can think of nothing more for it than to take them to the nearest base camp.

The year is 1917. The First World War.

The nearest Allied base camp is commanded by Major Barrington, a businesslike soldier dedicated and fearless. He reports to his superior an increase in fire power from the Germans. Likely they're after the nearby Allied ammo dump, but he vows that his men will stand firm. He is informed of the approach of an ambulance and orders protective fire for it.

Shortly, Carstairs, Lady Jennifer, the Doctor, Jamie, and Zoe are being helped down into a trench amidst fire from all sides. The Doctor and his friends wait, nervously, as Carstairs reports to Barrington. Carstairs explains that he was patrolling in no-man's land and got separated from his battalion and he explains how he recaptured the British ambulance from "the Huns". Barrington is not happy to learn that with everything else going on, he must now deal with three civilians.

Outside, the Doctor explains to his companions about this war, one of the worst in human history. He explains about trench warfare and "the war to end all wars". His companions don't really understand, but they do recognise his grim tone. Jamie worries that the soldiers might keep them here, but the Doctor is determined to escape and get back to the TARDIS. When the incessant gunfire dies down a bit, the Doctor takes the opportunity to try and climb out of the trench. He is forced back by another fusillade of gunfire.

Barrington's sergeant chastises him for his foolish act, caring little about their lost "transportation". He assures them that there's nothing beyond the trenches but "Huns". He leads the Doctor and his companions to the commander post and a meeting with Barrington. Lady Jennifer comes along as well.

Meanwhile, Barrington has received another call from his superior - General Smythe - and learned of a big push tomorrow. He and his men will go "over the top" at 0400 hours. He is glad of the action but fears the result. He kills time chatting with Carstairs. Oddly, neither man can seem to remember how long they've been at the front...

Barrington welcomes Lady Jennifer and listens to her story about picking up the three civilians in no-man's land. He doesn't really know what to make of these three odd people, although he accuses Jamie of being a deserter from a Highland regiment due to his kilt. Their protestations of innocence don't carry much weight with Barrington. When he learns from the sergeant that the Doctor tried to escape the trench in the direction of the German line, he decides to send them all to General Smythe at HQ. The decision in punctuated by a very loud and very close bomb blast.

Smythe's HQ is a chateau far from the front lines, taken over by the military. Its former opulence is hidden by rough military-issue furniture, graffiti on the walls, and taped-up windows. Smythe is an odd man, tall and stiff with a secretive streak. His assistant, Captain Ransom, is shocked to learn of the civilians captured between the lines. They are on their way here. Smythe retires to his room to await their arrival. Once there, he goes toward a framed picture on the wall but stops short when the Sergeant-Major brings him tea, entering without knocking.

Smythe's reaction is swift and merciless, barking out a reprimand which startles the Sergeant-Major. The response seems much harsher than the incursion would seem to warrant. The chastened soldier beats a hasty retreat. Once alone, Smythe pulls the picture aside on a hidden hinge, revealing a video communications device most definitely not invented in 1917. Smythe identifies himself by name, date, and sector to an unseen receiver, then requests reinforcements. At least 5000 "specimens" are required.

The Doctor tries to reason with Barrington, trying to avoid getting sent further away from the TARDIS, but Barrington is by-the-book and insists that the strangers give a proper accounting of themselves to General Smythe. Only that way can the cloud of suspicion around them be lifted. Tempers flare and Jamie is riled, not abating even when their transport to the chateau arrives. Jamie tries to leave the HQ, but he is stopped by a soldier with a rifle pointed directly at him. The Doctor decides they all should go quietly.

Lady Jennifer wishes them luck, not really believing that these people - odd as they might be - are spies. As Barrington goes to see about her ambulance, bogged down in the mud nearby, Carstairs tries to disabuse her of her Romantic notions. Spies never look like spies, he says, but if they are Smythe will suss them out. And he doesn't envy them their fate if they are. Smythe's nickname is "the Butcher".

Some time later, the Doctor, Jamie, and Zoe are marched into the chateau by an overzealous Sergeant-Major. Captain Ransom goes to fetch the General, who has not left his room since going in. However, when he enters, Ransom is shocked to find the room empty. Thinking quickly, he has the prisoners taken to the cells for the time being. The Doctor is confused, having hoped that a meeting with Smythe could clear things up, but he is given no answer to his question. He and his friends are marched back out again.

Back in the trenches, Carstairs and Lady Jennifer share a quiet moment over coffee, despite the constant shelling outside. Both of them seem to be affected by the same loss of memory. They know their jobs, but details of dates and places seem lost all together. Both are worried about this unexplainable phenomenon. The field phone rings and Major Barrington arrives to answer it. All three of them are wanted at the chateau to participate in an inquiry of the civilians. They decide to go in Lady Jennifer's ambulance so that she can go on from there...even though she still isn't sure where her hospital is!

The Doctor and his friends cool their heels in a cell whose door is very thick and very well locked. There's going to be no escaping this time. The Doctor, however, is not worried. He's sure they can explain themselves to General Smythe and he'll let them go, even though the other officers they've encountered haven't believed them up to now. Smythe, says the Doctor, is in charge and should be able to think for himself. Therefore they should be able to reason with him. Clearly the Doctor is unfamiliar with the distinctly odd man.

General Smythe leaves his room casually, addressing Ransom. Once again, he has appeared without anyone seeing him do so. Somehow he just vanished and then reappeared unseen by anyone. Ransom reports the arrival of the civilians and then tries delicately to broach the subject of his superior's seeming disappearance. Smythe responds by putting on a pair of small round spectacles and gazing hard into the eyes of Captain Ransom. In a stern tone, he insists that he was in the room and asleep when Ransom called earlier and Ransom did not wish to wake him. When Smythe is finished, that is what Ransom believes and all is well again. Odd.

Ransom explains the prisoners and Barrington's suspicions about them. A moment later, Barrington, Carstairs, and Lady Jennifer arrive. They sit down to talk but suddenly there is an awkward pause. Barrington recognises Ransom but due to the mental fog that seems to be affecting them all, he cannot recall from where. Again, Smythe puts on his spectacles and gazes hard. When he is finished speaking, Barrington "remembers" that the two of them were at school together. That settled, the inquiry can begin. Very odd indeed.

When the inquiry is concluded, the prisoners are marched before the General, unaware that they are now facing a court martial. The Doctor is stunned to learn this - things seem to be getting out of hand rather quickly - and he wishes to explain himself and his friends. Smythe cuts him short. This area is under martial law, civilians and all, and he is the ultimate authority. The Doctor will have a chance to speak in his defence...in due course.

Smythe reads out the "evidence" against them, a twisted and exaggerated version of the events of their discovery and transportation that paint the prisoners in a very bad light indeed. They "waylaid" Lady Jennifer's ambulance and led it into the hand of the German soldiers, then tried to escape the base camp toward the enemy lines at the first opportunity, with "whatever information they had gathered". The Doctor and his friends are horrified at this mockery of justice. They learn that Jamie is charged with desertion and the Doctor and Zoe with espionage. Both are capital crimes.

The Doctor is heartened to learn that he now has an opportunity to defend them, even being allowed to question the witnesses - Carstairs and Lady Jennifer. However, every attempt he makes to refute the "facts" of their bogus statements is stopped by Smythe. Whatever evidence these two people can provide has already been read into the record. In the end, the Doctor is allowed to present no evidence at all and in a complete travesty of justice, Smythe concludes the trial. He, Ransom, and Barrington retire to consider their verdict.

In the far corner of the room, the prisoners wait. It is clear to them: all that Smythe has some vendetta against them, but they cannot fathom why.

Barrington and Ransom, amazingly, are inclined to give the strangers the benefit of the doubt, even after the "evidence" mounted against them. The three strangers don't really seem like spies. But this is unacceptable to Smythe. The panel is already stacked against the accused and when Smythe puts on his spectacles and speaks tersely to his officers, the result is quick. He implants a guilty verdict in their minds and they both parrot his words: guilty as charged. The Doctor and his friends express little surprise when Smythe pronounces his verdict. For the crime of desertion in wartime, Jamie will be sent to a military prison to await a court martial from "his regiment". Zoe is sentenced to 10 years in a civilian prison for espionage. And the Doctor faces the ultimate punishment. Execution. At this, he lashes out, indignant over this travesty of a trial. He demands the right of appeal to a higher authority only to be told that he has no such right. He will be executed at dawn tomorrow!

Jamie reacts with anger and tries to make a break for it. He is grabbed by two soldiers and carted off for transportation to the military prison. Smythe leaves the room, no longer interested in the prisoners. Lady Jennifer appeals to Captain Ransom to leave Zoe in her care overnight. She doesn't feel it right for the young girl to rot in a cell, despite her crime. Freed from Smythe's influence, Ransom agrees. The Doctor is led back to his cell, but not before he bids Zoe goodbye, a sweet and poignant farewell that seems very like a final one. When he is gone, Zoe appeals to her friend Lieutenant Carstairs, who has been noticeably silent during the trial. But there is nothing he can do, even though he seems to agree with Zoe that they're all innocent. Ransom cuts through their speculation and they all heard the evidence and the verdict. They are all guilty.

The Doctor is returned to his cell by the Sergeant-Major, who promises to bring him some food - a last meal. The Doctor asks him how long he's been at the front, only to find that he is suffering from some form of amnesia. The Sergeant-Major blusters his way out of the question, leaving the Doctor with one more piece of evidence in a growing puzzle.

A short time later, Ransom brings they key of the Doctor's cell and gives it to Smythe for safekeeping. He hides it under his pillow, turns out the light, and stretches out to sleep.

The night drags on and everyone sleeps. All but Zoe. She waits for her chance and then sneaks away from Lady Jennifer, on a mission to free the Doctor. She heads for the General's room and is amazed to find it empty. She did not hear him leave but she has little time to worry over where he has gone.

Zoe searches the room and comes across the hinged picture frame. Behind it she finds the futuristic video communications device. But again, she doesn't spare much time on this strange anomaly. It is nearly dawn and she must hurry. What she wants is the key she saw Ransom deliver to Smythe earlier. More by luck than by skill, she finds the key beneath the pillow. Triumphant, she races to the Doctor's cell.

The Doctor has also spent the night without sleeping, pacing alone in his cell. He hears footsteps approaching and he hides behind the door, almost out of instinct. He knows there is little he can do against an armed guard. He is overjoyed to see not a soldier but Zoe. They have little time to talk. They must hurry before they are discovered and they make plans to try and find the prison where Jamie is being held.

However, they are already too late. As they turn to go, they run straight into Captain Ransom and his men. The time for the Doctor's execution has come.

The Doctor is to be executed by firing squad in the yard next to the chateau. The Doctor is marched to a stake in front of a column of soldiers, all armed and grim-faced, squinting into the brightening sun. Not for the first time in his life, things look hopeless for the Doctor. Zoe is also dragged out to watch, certainly Smythe's idea. Perhaps she'll learn a lesson. Ransom prepares his men. The soldiers present arms and take aim. The air is electric.

The bullet was not meant for the Doctor and was not fired by Ransom's men. The Doctor opens his eyes to see one of the soldiers in the firing squad fall, the victim of a sniper's bullet. Ransom and his men scatter, firing at the sniper, who is in the upper window of one of the outbuildings. He continues to fire at the soldiers. When Zoe's guard is hit, she wastes no time in dashing to the Doctor, who is staked out in the open. She unties him and they race for freedom.

What no one has noticed is that the man shooting from the window is not a German soldier...

Inside the chateau, General Smythe reports to an unseen listener via the video communicator. He is leaving for "the conference" now. Suddenly a cupboard-like box materialises out of thin air in one corner of the room, accompanied by a grinding engine noise not unlike that of the TARDIS. A door slides open and Smythe starts to enter.

At that moment Ransom enters to report what has happened, failing to knock. As before, Smythe is livid at the intrusion. Ransom is dumbfounded into speechlessness by the sight of the strange box, giving Smythe ample opportunity to produce his spectacles. Gazing hard at Ransom, he implants the idea that there is noting in the corner, that he has not seen Smythe, and that Smythe has been called away to an urgent meeting. With a smile of satisfaction, Smythe enters the box and it dematerialises.

This explains how the mysterious general can come and go from his room unseen, but Ransom does not have the benefit of this knowledge. When he regains himself, Smythe is gone and Ransom believes he has gone to a meeting...travelling by conventional means.

At the nearby military prison, Jamie is locked up alone, as he has been all night. He shouts out, asking for breakfast, but the guards who arrive bear something else - a cellmate. He is astounded to see an English Redcoat of the type he knew well back in his own time, powdered wig and all. The Redcoat also recognises his Highlander enemy, although this one is acting strangely friendly.

Jamie tries to make peace with the man, noting that they are both prisoners here. Jamie knows that this man has even less a place in this time than he has, but he is so confused that he cannot remember how he got here. He does, however, know the year. 1745!

The Doctor and Zoe have found their way to the prison, and the Doctor is certain they'll find Jamie inside. The difficulty will be getting past all the sentries. The solution presents itself in the form of a car approaching the prison gates. Calling forth his most officious manner and a deep reserve of bravado, the Doctor leaps out and stops the driver on the road, blustering his way into the car. He tells the driver that he was supposed to meet him and Zoe and is very late. The anger an authority in the Doctor's voice forestalls all questions. It's more than the poor soldier's job's worth. He simply drives on with two strange civilians in his car.

Jamie continues questioning the Redcoat. Thinking hard, he remembers getting lost in the Highlands whilst chasing rebels. And then there was a strange mist that overcame him. When he got through it, everything was "different". He saw giant guns, bigger than he'd ever seen before, and he saw carriages moving along without horses. Jamie knows full well the shock of seeing the future, but he cannot understand how this Redcoat came to experience time travel as well.

Jamie knows he must escape and find the Doctor, to tell him what he's learned, but to do so he'll need the help of his cellmate. Unfortunately, the Redcoat still sees Jamie as the enemy.

Meanwhile, the commandant of the prison, a petty military bureaucrat called Gorton, receives word of two civilians on the post asking to see him. He refuses to admit them until he's finished his tea, but he is in for a rude awakening. Into his office bursts a tiny, strangely-dressed bundle of righteous anger - the Doctor. He poses as an Examiner from the War Office whose patience has been sorely tested. Zoe is his secretary. "The Examiner" is livid that his arrival was not expected and that no car was sent to greet them. To add insult to injury, Gorton asks to see his identity papers.

The Doctor explodes with indignation, his performance seriously over-the-top. He threatens to report this shoddy treatment to "the Minister himself" and Gorton is soon shaking in his boots. He is too confused and frightened to resist, blames his adjutant for the mix-up, and offers "the Examiner" and his secretary some tea. The Doctor tells him tersely that he is here to inspect the security measures of the prison; there is no time for niceties. Gorton tries hard to hand on to his dignity.

Back at the chateau, Ransom has had no luck in tracking down the Doctor and Zoe. He has all his men searching and now enlists the aid of Lieutenant Carstairs and Lady Jennifer Buckingham. Carstairs is to search the chateau itself whilst Ransom searches farther afield. Lady Jennifer is to man the telephone and coordinate information. And she's to explain to the general should he return, a task he would rather not do himself.

Carstairs and Lady Jennifer are quick to obey their orders, but both of them agree they'd rather like to see the fugitives get away.

Back at the prison, a melee has broken out in one of the cells. Jamie and the Redcoat struggle on the floor, calling out loudly for the guards to help them. However, when the guards unlock the door and enter, the scuffling prisoners turn their attention from each other to the guards. Together, they knock out both men. Their ruse has worked. The two former enemies, working together, are now free.

Back at the chateau, Carstairs returns from an unsuccessful search. He's glad he's not in Ransom's shoes. Smythe will be furious at the escape. Lady Jennifer, in the meantime, has been doing some thinking. She recalls details about the court martial of the civilians and now thinks it highly irregular, although she stood silently by at the time. And she's also beginning to remember more details about her she got to the front. She remembers driving her ambulance in a forest, and then entering a thick mist. After that, she was in an entirely different part of the battlefield with a different job.

Carstairs at first chalks it up to amnesia, but the talk of mist triggers a memory in him as well. He speculates that perhaps it's a new type of poison bas invented by the Germans - one that affects the mind.

The Doctor, even as an untrained "Examiner", can see that the prison's security measures are more than adequate. Zoe agrees, somewhat grimly. Gorton is pleased. He shows the Doctor his record book. From it, the Doctor confirms that a "Highland deserter" recently arrived. "The Examiner" asks to interview the prisoner - a highly irregular request - and a single raised eyebrow from the Doctor warns Gorton not to question it.

The phone rings and Gorton receives the news of the two escapees. It would be bad enough under normal circumstances, but with "the Examiner" over his shoulder, it is much much worse. He tells the Doctor and Zoe that one of the escapees is the Scotsman who just arrived. The Doctor and Zoe exchange a glance of concern. Are they too late

? Jamie and the Redcoat skirt round one of the buildings, trying to avoid the patrols and looking for a way out. But they are far outnumbered and it is only a matter of time before they run into the guards. The soldiers open fire as Jamie and the Redcoat scatter.

Gorton receives word that one of the prisoners was shot while trying to escape. To the Doctor's relief, it was not Jamie. Putting on his bluster, he orders the Highlander brought here for questioning. Gorton chafes under the under these highly unorthodox requests, his patience with the odd little "Examiner" wearing thin.

Jamie is dragged kicking and struggling into the Commandant's office. He is shocked to see Zoe and the Doctor there and nearly gives the game away by speaking to his friends. The Doctor must act fast to cut him off each time, playing his blustery role to the hilt. Jamie finally gets the idea and relates in the worst possible detail how his comrade was shot in the leg and how the guards wanted to shoot him too.

"The Examiner" reacts in horror, promising a full inquiry, but he has now gone too far. Gorton knows his men acted according to regulations and he decides to call the Doctor's bluff. He picks up the phone to call General Smythe and enquire after this "Examiner". The Doctor sees his scam unravelling but can do nothing. In the end, Zoe saves the day, smashing a vase over Gorton's head and knocking him out. Crude but effective.

After checking to make sure Gorton's OK, the Doctor leads the way out. But the door is flung open ahead of them by a new arrival from outside. Captain Ransom. Wherever they thought they were going, they're going with him now.

Back at the chateau, Lady Jennifer and Lt. Carstairs continue to hash over the details of the court martial. Lady Jennifer is convinced it was rigged from the start. General Smythe wanted the Doctor shout and engineered the trial to make it happen. Carstairs is starting to believe it too.

They are interrupted by the arrival of a very relieved Captain Ransom. He reports that the prisoners have been recaptured, thanks to a last-minute thought of his to pop in on Commandant Gorton to warn him of the escapees. While he doesn't envy Gorton's position, nearly letting the prisoners go free as he did, Ransom does admire the Doctor's pluck in carrying off his Examiner charade so long. Almost seems a shame to shoot him.

At this, Carstairs plucks up his courage to lodge a protest over the court martial. He says it was not in accordance with King's Regulations. Ransom refuses to accept this. The trial was fair and impartial. The sentence will be carried out as soon as the general returns. With that, Ransom is gone. Lady Jennifer and Carstairs both agree that he was wrong. Somehow, Ransom doesn't remember the trial as it really happened. Somehow, Smythe has engineered this whole event to kill the Doctor. They must find out why.

Carstairs goes off to question the civilians whilst Lady Jennifer stays behind to stall Ransom upon his return.

In their cell, Jamie relates his encounter with the Redcoat, a man who believes the year is 1745. Coupled with the futuristic video communications unit Zoe saw in Smythe's room, this new information concerns the Doctor. How can these two anachronistic things be here in 1917

? At that moment, Carstairs enters, gun drawn. The guard closes the door behind him and his is alone with the prisoners, a grim look on his face.

Lady Jennifer completes her task of alerting all command posts that the hunt for the fugitives is over, just as Ransom returns. She tries to engage him in conversation about General Smythe's prolonged absence, but he doesn't really have much to say. Neither of them knows, of course, that this is exactly how Smythe has arranged it. When Ransom decides to go and check on the prisoners, Lady Jennifer must try again. This time, she asks about his job - about how hard it is to work for Smythe. Ransom is more than happy to regale her with horror stories about paperwork...

The Doctor has told Carstairs everything they've discovered, including the anachronisms. The earnest young man is inclined to believe them but he wants some proof. Zoe says she will show him the futuristic video unit if he'll take them to the general's room. Amazingly, he agrees to do so, putting his career - and maybe even his life - on the line to do it.

Ransom's treatise on military paperwork is cut short when the phone rings. Lady Jennifer snatches it up and Carstairs tells her to get rid of Ransom quickly. She makes up a story that Smythe called and wants Ransom to meet him at command post 17, the furthest point in the sector. He accepts this and hurries off, but not before thanking Lady Jennifer - perhaps a bit too sincerely - for "taking an interest in the problems of supply".

After making sure Ransom's gone, Carstairs races in with the prisoners, much to Lady Jennifer's surprise. She follows them all into Smythe's room, but cannot understand why they're all looking at the blank wall behind a hinged picture. Neither Lady Jennifer nor Carstairs can see the video unit. The Doctor's credibility is sinking fast.

The Doctor urges them both to concentrate on the wall, trying to undo the conditioning which blocks their minds. After a moment, the glowing video screen and its controls at last become visible to them. They are stunned. Zoe explains it as a sort of visual telephone and all wonder what's on the other end. The Doctor is horrified to realise that the unit is on and transmitting and he quickly switches it off.

However, they have been seen on the other end. By General Smythe and a strangely-dressed technician.

Whilst the Doctor and his friends could see no one on the screen, he is almost certain that they were seen by someone on the other end. All of their lives will now be in danger. They must leave this place at once. Carstairs is reluctant to accept all this and to let his prisoners go. However, when Lady Jennifer places her trust in the Doctor, Carstairs relents. They will all go together in the ambulance.

Lady Jennifer gets to fetch it whilst Carstairs gathers some maps of the area. Jamie hopes they're heading back to the TARDIS, but he really knows better. They must stay here and find out what is happening. However, before they can get out, Ransom returns, non too pleased at being sent on a false errand to meet the general. Carstairs tries to bluff their way past, saying he's taking the prisoners to HQ on Smythe's orders. Ransom is dubious but in the end relents, having no reason to doubt Carstairs' word. He would, however, like a word or two with Lady Jennifer.

Whilst Ransom looks for her, the fugitives load up in the ambulance and hurry away.

Meanwhile, Smythe returns to his run via the cabinet, materialising from thin air. He notes the absence of the Doctor and his friends and inquires of Ransom. With a sinking heart, Ransom realises that Carstairs lied to him as well. Smythe is furious. Lady Jennifer and her ambulance are gone. A general order goes out immediately to find that ambulance.

It is spotted a short time later in sector 4, travelling eastward very fast. Ransom is relieved that he may still have a career. However, he is stunned when Smythe orders their own artillery in the sector to open fire on it. He protests, reminding Smythe that there are two women on board. Smythe simply puts on his spectacles and implants the order firmly in Ransom's mind. A creeping barrage soon sounds a brilliant idea to him. It will stop them dead.

The ground and air soon erupts all round the ambulance. The Doctor is certain this is Smythe's work and they must get way. He won't rest until they are all dead. The Doctor directs Lady Jennifer to drive off the road in an effort to evade the shells. Suddenly, as the ambulance moves forward, it vanishes from sight.

The Doctor and his friends find themselves in a misty void, a nothingness filled with silence. It is the mist that Lady Jennifer, the Redcoat, and Lieutenant Carstairs encountered before. Carstairs once again calls it a gas. It seems to fill them with dread and Lady Jennifer cannot drive on. The Doctor takes over the wheel and moves them onward.

The ambulance emerges on a rocky road near a hillside. The guns have stopped and the landscape is very different from the muddy and desolate no-man's land. There is no sign of the war here. They disembark to look around. The Doctor believes the mist they passed through was a force field of some kind, designed to keep the likes of Carstairs and Lady Jennifer from crossing. He, Jamie, and Zoe climb the hill to get a better look. What they see is startling. A small troop of Roman soldiers, led by a charioteer, bears down on them, sounding very fearsome indeed.

Carstairs manages to get the ambulance started as the Roman soldiers approach. He climbs in and Lady Jennifer backs the vehicle away. It vanishes from sight, leaving the incredulous Romans awestruck and speechless.

After traversing another misty void, the ambulance reappears in its own time, back in no-man's land. Shells explode all round, but they are safe for the moment. Carstairs and Lady Jennifer climb in the back with the Doctor, Jamie, and Zoe, both clamouring for an explanation of what just happened. The Doctor announces that they have passed through time and visited a land 2000 years in the past. All are amazed and not a little sceptical. But for the Doctor, it all adds up.

The mist they passed through was not a German gas, but a force field barrier between time zones. He points out the map that Carstairs got for them. Where the Roman soldiers were is off the edge of that map and coincides with the barrier. He assumes there are even more time zones here and other barriers. They must find a map that shows all the time zones and to do that, they must go back to the chateau. He is certain that the mysterious General Smythe will have such a map.

A short time later, Carstairs conducts the Doctor and Jamie into the chateau at gunpoint to face a very angry Captain Ransom. Carstairs tries to pull off the ruse that he has captured and returned these two prisoners, but Ransom will have none of it. He knows Carstairs is in league with them. Carstairs abandons the pretense and turns his gun on Ransom, knowing that he risks a court martial and a firing squad if the Doctor is wrong.

Jamie disarms Ransom and the Doctor provides bandages with which to bind and gag him. The Doctor has found only local maps in the main area of the HQ and goes into Smythe's room to search further.

He finds a safe there, made of solid iron and firmly locked. The only way in is to blow it open. Carstairs is dubious but goes off to find some explosives. The Doctor sets about trying to pick the lock. Jamie is dubious about that, recalling the Doctor's recent ear-splitting efforts to use a tuning fork to trip a lock on the planet Ta. The Doctor has no luck, but Carstairs does return with a hand grenade. The Doctor thinks it will work, but not without some modification.

To Carstairs' horror, the Doctor begins dismantling the grenade somewhat indelicately. He is successful at extracting the detonator and in pouring out the explosive onto a piece of paper. He intends to pack the explosive into the lock and detonate it using a candle wick as a nice long fuse.

However, just as the Doctor completes the setup, a cry for help issues from the HQ. Ransom has somehow slipped his gag. Carstairs races out to silence him. He is successful, but as he stands he sees a new arrival, a young soldier looking for Captain Ransom. Ransom is hidden behind a chest and cannot be seen but the young soldier is insistent to find him. He has as his prisoners Zoe and Lady Jennifer, found hiding outside in their ambulance. Carstairs tries to bluff, but the soldier is well aware of the "spy flap" earlier and things he may have caught two of them. He becomes suspicious of Carstairs.

Inside Smythe's room, the Doctor is unaware of Carstairs' plight. He lights the fuse and he and Jamie stand well back, covering their ears.

The soldier is becoming increasingly concerned over Carstairs' attitude and he refuses to leave his prisoners with Carstairs. His voice rises and soon Jamie can hear it, even through the pillow over his ears. He draws the Doctor's attention to the noise, although his eyes never leave the ever-shrinking fuse.

At last Carstairs is able to convince the soldier to leave the women with him, promising to alert Ransom when he returns. The soldier turns to go but lingers in polite conversation a moment more. In Smyth's room, the Doctor decides he must put the fuse out or risk giving themselves away, but it is now too late. Just as the soldier leaves, the explosive goes off, rocking the room. The soldier races back in and goes straight to Smythe's room.

Carstairs pulls his gun and disarms the shocked soldier. He now realises that he has been talking to "the traitor Carstairs" all along. Jamie ties the young soldier up. The Doctor has succeeded and he removes a map from the safe. It shows a number of triangular divisions along the landscape, each labelled with the name of another war. 1917 zone, Roman zone, American Civil War zone. Very odd. In the centre of the map is a blank spot, unlabelled and undetailed. That, says the Doctor, is where they must make for.

Soon the group are back in the ambulance, traversing no-man's land toward the blank space on the map. Unfortunately, there's still a war on. They are stopped by a German patrol. The Doctor insists they are a medical detail transporting a wounded officer. Carstairs' acting must be good because this ruse works. The Germans don't kill them all, but they do take the ambulance and its occupants prisoner.

They are taken to the German HQ in the trenches. Jamie and Zoe are forced to sit out in the open with bombs exploding all round them. Lady Jennifer has been left in the ambulance to take care of the "wounded" Carstairs. They only hope the Germans don't check his "wounds" too closely. Meanwhile, the Doctor is in with a German Lieutenant for questioning. They hope he can talk their way to freedom.

The German Lieutenant is a tall and imposing young man, towering over the Doctor. But the Doctor keeps his tone friendly and his answers brief, hoping to gain some sympathy. But the officer is determined to find out who he is and why he is here. The Doctor calls himself "John Smith" - a pseudonym Jamie first gave him on the Space Wheel - just so that he appears to be cooperative. The Lieutenant accepts this, but he does not accept the innocent explanation that the ambulance and its occupants simply lost their way in no-man's land. He believes the Doctor and his friends to be spies. He pulls his pistol and points it at the Doctor, advising him to tell the truth immediately.

Jamie and Zoe are given helmets to protect themselves from flying debris, but that is all. They are almost ignored by the busy soldiers. Neither of them can understand this bizarre trench warfare, and both just with to get out of here.

In the HQ, the Doctor has decided to do as instructed and tells the Lieutenant about the TARDIS and its ability to travel in time and space. He hopes that his sincerity will win through, thinking that that no harm will come to them by mentioning time travel. Of course, the Lieutenant is sceptical, but he does bring in Jamie and Zoe, who corroborate the Doctor's story and relate their first meetings with him. This adds a shade of truth, but the Lieutenant is afraid he will be thought mad if accepts their story.

The Doctor offers more proof, producing his sonic screwdriver and using it to remove the screw in the handgrip of the Lieutenant's pistol and put it back without touching it. He has never seen anything like it and is on the verge of believing the Doctor's story. However, the matter is taken out of his hands when his C.O. arrives, an odd little bald-headed Captain called von Weich.

Von Weich takes in the time travel story from his subordinate and can easily sense his acceptance of it. After a cursory examination of the prisoners, he leads the Lieutenant outside for a moment's conversation. Von Weich fits a monocle into one eye and turns his gaze on the Lieutenant. In harsh German, he implants his will in the mind of the Lieutenant, just as General Smythe did with his men.

The Lieutenant returns to HQ almost in a trance. He denounces the shocked prisoners as dangerous English spies and tells them they will all be shot.

In his quarters, von Weich has a video communications unit hidden behind a picture, just like Smythe. With it he contacts "Central Control" to announce the capture of three civilians from the British sector. He also reports their claim to be time travellers.

The Doctor hurriedly tries to break the mental control that has been exerted on the Lieutenant. Once again, he shows him the sonic screwdriver and the fantastic demonstration breaks the hold. The Lieutenant is once again calm and friendly. However, with the dangerous von Weich about, the Doctor has no time for niceties. He must use the Lieutenant's friendliness against him, stealing his pistol. With Jamie in control of the gun, the Doctor orders the Lieutenant to take them back to the ambulance.

In the centre of General Smythe's map, there is a blank sector. As the Doctor suspects, it is the location of Central Control, the base for those controlling the time zones and what happens in them. Central Control is a futuristic place, very large and full of people. Black-clad guards and white-clad technicians - all in strange slotted eyewear - mingle with people in various military uniforms from Earth's past. The place is bustling. General Smythe is there, working at a desk with a map built into it.

Smythe stands at attention when an alarm sounds. It heralds the arrival of his superior, not another soldier but a civilian. He is small and dark with slicked-back hair and an air of confidence. He is the War Chief, in charge of operations here. He brings greetings from their leader, the War Lord. He is pleased at their "progress" so far, but wishes operations speeded up.

Smythe reports that the three civilians from the 1917 zone have been recaptured. Clearly the Doctor's presence has caused some consternation in the highest circles. Smythe says he's ordered them shot but the War Chief countermands that order when he learns of their claim to be time travellers. He seems very interested in this fact, despite Smythe's scepticism.

Von Weich reports that the prisoners have escaped, blaming his gullible Lieutenant, a mere human. Smythe is furious at him, but the War Chief reminds Smythe that they escaped from him too. The War Chief orders them found, captured alive, and brought to Central Control. Smythe issues a general alert to all time zones, warning the other commanders, like himself, to be on the lookout for the 1917 ambulance, no matter which time zone they end up in. Clearly, Smythe, von Weich, and the War Chief are not human. However, the soldiers who fight and die under them are. Somehow, human beings have been enslaved by these aliens with knowledge of time travel. The War Chief seems quite concerned over these strangers, especially their own claims of time travel. He even seems threatened somehow.

Back in the time zones, the ambulance has passed through another mist - another barrier - and the Doctor thinks they've arrived in America, 1862. The American Civil War, according to the map. Suddenly the ambulance is attacked by a sniper in the trees. A Confederate soldier. Carstairs orders Lady Jennifer to get the vehicle moving again. They are safely out of range of the shots in a moment. The Doctor is glad at least to know that they're still on the right path. They are still heading toward the blank space at the centre of the map.

However, it will not be smooth sailing. A tree comes down in the road, blocking their way. Carstairs is certain it is a trap, but they must risk moving it or else they'll be sitting ducks. He is right. Before they can get the tree moved, shots ring out. Carstairs fires back, scattering the soldiers long enough for Jamie, Zoe, and the Doctor to move the tree out of the way. But the soldiers are soon on top of them and both Carstairs and Jamie must resort to hand-to-hand combat before they can get the ambulance clear. The Doctor, Jamie and Zoe clamber inside whilst Carstairs provides covering fire. But when a mounted troop of Confederate soldiers appears over the hill, Carstairs urges Lady Jennifer to drive on without him. It will take some work to escape from this lot.

Lady Jennifer only drives a short way before she is forced to stop. Luckily, another mounted patrol passes by without seeing the ambulance. But there is another problem they face, this one insurmountable. They have run out of petrol. There is only one thing for it, they must go on by foot. They can only hope Carstairs will soon join them.

Back at Central Control, Smythe and von Weich play a particularly nasty game. A war game. They plot the movements of a battle between British and German soldiers - human soldiers. They plot and play with the lives of their human soldiers as casually as toys. There is no doubt that the battle will come and that many men - many humans - will die. The deaths seem to mean very little to the aliens, only the morale of the survivors.

The War Chief interrupts them with the announcement that one of the time zone jumping fugitives has been captured. A British Lieutenant. Von Weich is amazed at the loyalty the humans show to each other in stress situations, even going so far as to allow oneself to be captured to save others. He speaks of it in an academic sense; the War Chief agrees, but admires the trait. Lieutenant Carstairs is being returned to Central Control for "re-processing".

The Doctor, Jamie, Zoe, and Lady Jennifer make their way to a barn, checking carefully to make sure it's unoccupied before entering. Zoe is worried about Carstairs but there is nothing they can do for him now. The Doctor insists that they carry on toward the blank space on the map. That is where they will find the answers they need. But first they need to get some rest.

However, the peace is shattered by a raucous grinding engine noise. Another of the large green boxes appears from this air. From it emerges a large contingent of Confederate soldiers. They do not see the hidden fugitives and they head out of the barn. Everyone is amazed. Zoe notes that the box must be larger inside than out to contain so many men. Just like the TARDIS.

The Doctor ventures inside cautiously to investigate whilst Zoe tries to explain to Lady Jennifer about the nature of a time/space travel machine. Suddenly gunfire erupts outside. Zoe calls to the Doctor but he does not respond. Impulsively, she goes inside after him. Lady Jennifer goes to the door of the bar to see what the commotion is, risking her life. Torn, Jamie goes to stop Lady Jennifer and keep her from being shot. When he does so, the door to the box glides shut, trapping his friends inside.

Jamie is helpless to regain his friends. He and Lady Jennifer are all alone. But their plight gets worse as they are captured by a group of Union soldiers who invade the barn.

The Doctor and Zoe find themselves inside a vast, cavernous space in the small box. It is just like the TARDIS, bigger inside than out. And it is clearly a time/space machine. Just like the TARDIS.. The Doctor has a nasty suspicion as to the machine's origin, but he doesn't elaborate, preferring to explore further. Down a short corridor, he finds a group of German soldiers, circa 1917, standing blank-eyed and motionless. The Doctor thinks they must be in a hypnotic trance. In another room, a group of Roman soldiers stands in the same state. They are here, the Doctor surmises, to fight.

Suddenly the engine sound fills the machine. It is landing again. Zoe and the Doctor hide in an anteroom and watch as the Roman soldiers troop out, just as the Confederate soldiers did earlier. Zoe wonders if they should disembark themselves, but the Doctor says no. There's only another war zone out there. They must stay in the machine until it returns to its base. The door to the machine closes and they are off again.

Jamie and Lady Jennifer are finding it difficult to explain themselves to the Union soldiers, but their accents lead the soldiers to suspect they must be English spies working for the South. This whole spy business is becoming quite tiresome to Jamie, who doesn't even know who is fighting whom in this particular war. Lady Jennifer tries to assert that they are neutral civilians but to no avail. They will have to await the arrival of the Union general to decide their fate, but he doesn't take kindly to spies, Jamie and Lady Jennifer are told. He will likely shoot them both.

The Union sergeant announces a 10-minute rest, but a mere second later, gunfire erupts outside and the sentry is shot. A rebel attack. Whilst the guns blaze, Lady Jennifer uses Jamie's dirk to try and free them both. The prisoners are completely forgotten as the soldiers flee the barn for the safety of the woods.

Jamie and Lady Jennifer have but a moment's respite until a group of Confederate soldiers takes control of the barn. To their delight, the soldiers release them, talking of the Yankee dogs who would tie up a lady. Just like 'em. Things are looking up for Jamie and Lady Jennifer. But not for long.

In charge of the Confederate group is a very familiar-looking Captain. It is von Weich, still with shaven head and monocle, but now wearing the uniform of a Confederate captain. He convinces his subordinate - using mind control - that Jamie is a Yankee soldier and Lady Jennifer is a spy. Both are tied up once again.

Back at Central Control, the War Chief pays a call on the Chief Scientist. The strange little man is preoccupied working on a piece of machinery and has little time for this inquiry. The War Chief is concerned over lapses in the mental processing to which the human soldiers are subjected. There is a 5% failure rate at present. This is within normal parameters, says the Scientist, given the difficulty of exerting mental control over humans, but the War Chief says this is unacceptable. Those whose processing has lapsed are already banding together out in the time zones, causing trouble everywhere through sabotage and mischief. If ever they are all concentrated into one large group, they could threaten the plan. The War Chief insists the processing be improved to eliminate these failures.

The Scientist reports with some irritation that improvements have already been made. He is going to present a lecture to "the students" on that subject momentarily.

A call from von Weich is routed here for the War Chief. He reports the capture of Jamie and Lady Jennifer. Only two more of the escapees are at large and soldiers are hunting for them now. The War Chief is pleased. Soon they will all be back here, perfect specimens for the Scientist's reprocessing tests.

The time machine lands again, but it is now empty of soldiers, having dropped off all those inside. The Doctor determines that this must be the machine's base. Zoe notes that the machine is operating by remote control, worried about what sort of reception committee might be waiting outside. The Doctor points out a small control panel. He may be able to override the remote control if need by and use the machine to return to Lady Jennifer and Jamie.

The machine's controller is a technician at Central Control, wearing a white tunic and the strange slotted eyeglasses like all the others. He has his back to the landing bay and does not notice when the Doctor and Zoe emerge from the newly-arrived machine. Zoe notes the eyeglasses and shows the Doctor two pairs that she found in the machine. They both put them on and now look like almost everyone else in Central Control. Emboldened, they head off to look around.

Jamie and Lady Jennifer have been kept prisoner through the night in the barn whilst the search has continued for their friends and "fellow spies". They try again to explain to the soldiers that they are neither spies nor Yankees, but no one is listening. They are left to wait in the corner whilst their guards return to their card game.

The two prisoners try to loosen each other's ropes, but they have been at it all night whenever they had the chance and are still no nearer to freedom. Suddenly a hand reaches out to cover Lady Jennifer's mouth. It is a man in a Union uniform, armed and stealthy. He quietly unties them and leads them toward the door. At the last minute, the guards see them and open fire. Jamie and Lady Jennifer escape, but the soldier - a man called Harper - is captured.

Von Weich arrives in the wake of the firing, hoping mad at the loss of the valuable prisoners. Soldiers are sent after the escapees whilst von Weich concentrates on Harper. He will say nothing and not even von Weich's mental conditioning will work. Harper is one of the "resistance", human soldiers who have broken the mental conditioning. Harper knows they are not really fighting the war between the states and he knows that von Weich doesn't belong here at all. He tries to get the other soldiers to see this too, but it is useless. They are full under von Weich's mental control.

Out on the hills, Jamie and Lady Jennifer have become separated. He calls for her, but only succeeds in attracting a soldier on horseback. He attacks, sword drawn, but Jamie is an old hand at this sort of fighting. He knocks the soldier off his horse, appropriating the mount for himself. He gallops off, avoiding the soldier's bullets.

The Doctor and Zoe's exploration has revealed an immense complex: reception areas, living quarters, even lecture halls. It seems just like a university, some sort of training school. They see a group of people in the dress of various periods, all wearing the same type of slotted eyeglasses. The Doctor and Zoe are mistaken by a guard as part of the group and are ordered to follow. They are late, the guard says. The lecture has already begun.

The Chief Scientist is conducting his lecture on the mental processing of humans, and he is clearly enamoured of the sound of his own voice. He repeats a lot of information the students likely already know just to hear himself talk, but the information is a bonanza for Zoe and the Doctor. They learn - as the Doctor had suspected - that this is not Earth at all, but an alien planet designed to look like various places and times in Earth's history, all connected to wars. The soldiers here are humans kidnapped from Earth and brainwashed into thinking they are still fighting their respective wars. The mental processing allows them to continue fighting.

The Scientist goes on to say that certain individuals of strong character have managed to overcome the processing and have been able to pass through the time zone barriers, normally impossible in processed humans. Their increasing resistance activities might threaten the "major plan". Because of this, he has developed a newer, more effective form of processing that will be permanent even on these specimens.

The subject for the test is Lt. Carstairs. Two guards bring him forward strapped to a trolley. The Chief Scientist, in full lecture mode, demonstrates that Carstairs' processing is completely lapsed. He does so by asking the man to describe his surroundings. While he can't explain the futuristic equipment, Carstairs can see it all as well as all the strange people in strange eyeglasses staring at him. He notices the Doctor and Zoe and is very surprised indeed to see them here. The Doctor gestures for him not to give the game away. So engrossed is the Chief Scientist in his own brilliance that he doesn't notice this contact.

The Scientist produces a pincer-like device on a stand and places its two prongs around Carstairs' head. The machine - a prototype of the newly-advanced processing machine - goes to work on Carstairs' brain. Soon he will be back under control. Zoe and the Doctor watch helplessly as the process reaches its conclusion.

Carstairs is released from his trolley, looking tired from his experiences. The process seems to have worked. He now translates everything around him into something familiar to his time and place. The Scientists is his commanding general, the room is their HQ, and the students are fellow officers. That which he cannot understand - like the processing machine - he cannot see at all. This is why he and Lady Jennifer could not at first see the video communications unit in General Smythe's room. The Doctor is duly impressed at the depth of the mental processing. It will be a chore to undo it, but that is what he must do.

However, the conditioning is perhaps too strong now. As Carstairs looks at his "brother officers", he spots two people who don't belong, two incongruous individuals that his mind tells him are German spies. He points them out for his "general". It is Zoe and the Doctor.

Back in the war zones, Lady Jennifer races away from a mounted soldier who has chased her for sport through the hills. She at last collapses and the soldier dismounts to take her into custody. Riding to the rescue, Jamie arrives and fights off her would-be captor. But they are too late to get away. A group of von Weich's soldiers appear on the hilltop with weapons at the ready. Jamie and Lady Jennifer are prisoners again.

Back at Central Control, Carstairs is tied - with difficulty - back on his trolley. He raves on about the German spies, unable to understand why his "general" won't believe him. He's carted off and the Doctor breathes a sigh of relief. The Chief Scientist has made the assumption that the re-processing experiment has failed and that Carstairs is seeing things. He is certain - quite wrongly of course - that there are no "German spies" among his students. The Doctor moves boldly forward and begins examining the processing machine. The Scientist makes several suggestions as to why the failure occurred. The Doctor is able to shoot them all down, poking holes in the pompous Scientist's ego along the way.

The Doctor boldly offers his own suggestion: Carstairs' original processing hadn't completely lapsed before he was re-processed. He suggests complete de-processing should have been carried out first. The Doctor doesn't believe this for a moment and is merely fishing for information. And he has don't it very well by challenging the Scientist's conclusions. The Doctor learns that the processing machine can also be used to de-process the humans and is even shown which circuits to use. The information is invaluable.

Jamie and Lady Jennifer meanwhile are returned to the bar and tied up with Harper. He tells them that he is part of the resistance and he recognised them as being from another war. That's why he rescued them. He starts to tell them of the other soldiers in his resistance group who have shaken off the mental processing and can pass through the mists - the time zone barriers - but he stops when von Weich appears.

Von Weich demands to know where the Doctor and Zoe are, but before Jamie can fully express his anger in response, gunfire erupts outside. A group of soldiers, all wearing different uniforms from wars far removed from the American Civil War, attack the barn en masse. They eventually succeed in killing or driving out the Confederate soldiers. Captain von Weich is captured.

Harper is ready to kill von Weich where he stands, knowing him to be "one of the people running things around here", but Jamie stops him. He thinks they can make use of him as a prisoner. Harper, however, is not to be deterred. He vows to kill von Weich, and Jamie too if he interferes.

The Chief Scientist completes his explanation of de-processing, not noticing the keen interest with which the Doctor takes it all in. The class is dismissed but all the students stop in their tracks as an alarm sounds and the War Chief appears, along with a phalanx of guards.

He has come to inquire about the success of the re-processing experiment and is disheartened by what he hears. However, when his attention is drawn to the Doctor, all thoughts of the experiment are forgotten. The Doctor has absently removed his glasses - which obscured most of his face - and the War Chief can see him clearly. There is a spark between them - like recognition - and the Doctor's face fills with fear. He shouts to Zoe to run!

They burst through the crowd of confused students and race through the corridor, hotly pursued by the black-clad guards. An alarm sounds throughout Central Control. In the confusion, Carstairs slips his bonds and escapes.

The War Chief issues a general alert to all guards to find and capture the escapees. He calls them "resistance members", but his tone suggests that he thinks they are rather more than that.

The Doctor and Zoe have managed to slip their pursuers, but they have become separated in the process. Zoe reaches the landing bay for the time/space machines and finds it empty. However, she is not alone. Carstairs springs from hiding and grabs a surprised Zoe. She is at first glad to see him, but he is no longer the friend she once knew. To him, she is a German spy. It is his duty to shoot her.

Carstairs is stopped by the stern voice of the Chief Scientist, just arrived on the scene. He knows Zoe is wanted alive and orders Carstairs not to shoot. But so strong is the mental processing that Carstairs cannot let go of his belief in his mission. As Zoe squeezes her eyes shut in fear, he pulls the trigger. However, his gun is empty, used up long ago against the Confederate soldiers. The Scientist exerts his influence over Carstairs' confused mind and he stands to attention. Zoe is taken away for questioning by the guards. Carstairs will come with him. There is still work to be done.

Back in the time zones, Jamie and Lady Jennifer have convinced the resistance fighter Harper to spare the life of Captain von Weich. He has not done so happily and Jamie and Lady Jennifer are as much prisoners as von Weich is. Harper is awaiting the arrival of Russell, leader of this resistance group. He will decide what is to be done with the prisoners.

While he waits, though, he tries to get information out of the obstinately silent von Weich. Harper and the others have kept watch on this barn and they have seen wave after wave of new recruits coming out of it. He believes there is a tunnel in here from which they come and he tries to force von Weich to reveal its location. Jamie and Lady Jennifer try to tell Harper of the "big green box" which really deposited the soldiers here, but it is too much for him to accept. He and the others hope to use the tunnel to get out of here and return home, even though they don't know where "here" is.

However, not everyone feels this way. A Redcoat soldier arrives and reports that their supplies are loaded. He does not believe there is a tunnel and just wants to get away from here and back to their HQ. He load his rifle casually, and in direct defiance of Harper, prepares to shoot von Weich, a worthless prisoner. A fight breaks out between the two men. Many of the other resistance fighters simply watch with amusement, illustrating a wide division between the men in this loose-knit group. One does eventually intervene, to stop the Redcoat from shooting Harper, but it is likely only to prolong the fight.

As the tussle continues, degenerating into a wrestling match, Jamie and Lady Jennifer attempt to escape. They are stopped by the arrival of another man, tall and imposing and clearly in command. It is Russell, a Boer War soldier, leader of this resistance group. He stops the fight by firing his pistol into the air. He is disappointed by their behaviour, but not surprised, He orders the Redcoat to take their supplies back to HQ and he admonishes Harper for not keeping himself under control.

In the commotion, von Weich has been forgotten. Jamie notices him working at a piece of wall board. Behind it is a video communications unit. Jamie leaps forward and stops him activating it, but the futuristic device is now visible for all to see. Perhaps this will convince them that Jamie's story is true.

Back at Central Control, the captive Zoe is taken to the security section by a silent and heavily-armed guard. There she is greeted by the Security Chief, another of the strange aliens - ramrod stiff, single-minded, and ruthless. He subjects Zoe to questioning under the influence of the truth machine. It is a helmet and visor contraption which bores into the prisoner's mind and forces her to tell the truth.

The questions asked by the Security Chief indicate that he believes her to be a member of the resistance - a kidnapped human brought here to fight. She tells him that she was born in the 21st century, far ahead of the latest time zone represented here, and that she arrived in a time machine called the Doctor, operated by the Doctor. Persisting, the Security Chief shows Zoe a parade of photographs of known resistance soldiers, hoping she will identify them and give herself away.

Still on the loose in Central Control, the Doctor finds himself back in the lecture hall/laboratory where the Chief Scientist is surprised indeed to see him. Thinking quickly, the Doctor tells him that the girl, not he, was the subject of the general alert. He only ran from the lecture to try and catch her. Not one to waste time on anything not directly involving himself, the Scientist accepts this story. He tells the Doctor that Zoe has indeed been caught and is being questioned in the security section.

The Doctor re-adopts the role of helpful student as the Scientist works on his processing machine. Lieutenant Carstairs sits dazed on the trolley before him. As the Scientist prepares to de-process Carstairs - an idea he took from the Doctor - the Doctor himself tries to get more information on the "major plan" mentioned before. He learns little, only that the War Chief is the only one who knows all the details of the plan.

De-processing begins and the Scientist asks his new assistant to strap Carstairs down. He's bound to be hostile after the processing is removed. The Doctor feigns this action, leaving his friend free. When Carstairs is finished, he is pleased to see the Doctor. The Scientist realises he's been duped by a member of the resistance, but it's too late then. Carstairs grabs him and forces him down onto the trolley. The Doctor reactivates the processing machine and places it round his head, trapping him.

Carstairs is still a bit fuzzy, remembering nothing after his capture in the American Civil War zone, but he accepts the Doctor's explanation. After turning the processing machine down to "simmer", so as not to permanently scramble the Scientist's brain, the Doctor leads Carstairs away to try and find Zoe.

In light of the video communications unit, Russell is a bit more swayed by Jamie's story than Harper was. However, the disappearing box is still a bit much for him. As they talk, von Weich lunges for the communications unit and manages to activate the emergency circuit. He is very proud of himself. Jamie - and even Russell - are very worried about what may be brought down upon them now.

At Central Control, an alarm is received from the American Civil War zone, but it is not followed by a message. Very strange indeed.

In the security section, Zoe's questioning has finished for the moment and she slumps unconscious in her seat. The War Chief arrives unannounced, wanting to know what the Security Chief has learned. There is clearly no love lost between these two "allies". He says that Zoe and her friends are from a previously-unknown resistance group, small and independent. Two members are still at large in the American Civil War zone and 1 is still at large in Central Control, a fact which chafes the Security Chief and gives some joy to the War Chief.

The War Chief wishes to know what time zone this group originates from and the Security Chief says 1917, even though Zoe did not admit this at all. He is unaware that the War Chief has heard their story of time travel before but is suspicious when the War Chief persists in his questioning. Neither man will admit what he knows and the wall of mistrust between them grows stronger, each suspecting the other of holding out.

This paranoid stalemate is interrupted by a report of the emergency call from the American Civil War zone. To the War Chief, this news takes precedence over the prisoner and he forces the Security Chief to come with him to the control room.

The Doctor and Carstairs see the two men leave the room and decide to investigate. Sure enough, this is the security section and they find Zoe. The Doctor distracts the guard and Carstairs knocks him out, very easily indeed. Using smelling salts, the Doctor revives Zoe. She tells him about her questioning, particularly the photographs she was asked to identify.

The Doctor puts on the headset and runs the pictures for himself. He realises that they are all resistance fighters known to the alien overlords. He also realises that Zoe will be able to remember them all due to her keen memory. If they can go back out into the time zones and track these men down, they can organise the scattered resistance groups into one big army to fight the aliens. To do that, they must get hold of one of the travel machines. They all head off to the landing bay.

Meanwhile, the War Chief challenges the Security Chief to respond to the mysterious emergency signal in the American Civil War zone. With no message and no idea what the real emergency is, he chooses a heavy-handed approach. He orders his security guards to the landing bay. They will be despatched to the zone to investigate.

The Doctor, Zoe, and Carstairs see the guards on the move and hear the alarm. They follow. At the landing bay, they watch as a time machine is summoned.

Back at the barn, the resistance fighters are prepared for an attack with sentries posted all round. However, Lady Jennifer and Jamie realise the expected attack won't come from outside. It will come from inside! At that very moment, the laboured engine sound of one of the machines fills the air. Jamie was right. The entire gathered group hides as the box materialises in the centre of the barn.

The guards emerge cautiously, but the see no one. Harper is first out, leaping from hiding to attack them. But the guards are too quick. They turn and fire at him with their futuristic weapons. Harper clutches his head and falls to the ground, dead. The rest of the soldiers leap out and capture the guards, overwhelming them with sheer numbers.

Russell cannot understand how Harper was killed. There's not a mark on him. The strange rifles are like nothing he's ever seen before and he cannot figure out how to work them. Too bad. He also examines the green box, its door still standing open. Russell is much more accepting of Jamie's story now, which is good as Jamie has a new idea...

Back at Central Control, the War Chief and the Security Chief await word from the guards. The War Chief takes great delight in the Security Chief's lack of success in catching the fugitives. Also, he notes the increase in resistance activity and lays that failure at the Security Chief's feet as well. Still quite self-assured, the Security Chief turns the tables. He wants to know how the War Chief recognised the Doctor and Zoe as "resistance members" when he saw them here. From what he can determine, they did nothing to give themselves away. Seeing what he's getting at, the War Chief reacts with indignation and threats, refusing to accept any blame for the difficulties.

It is revealed that whilst the War Chief is not human, he is also not of the same race as the Security Chief, von Weich, the Chief Scientist, and the others. He came to them with a plan and certain expertise. The rest was up to them. His implication is that his partners are falling down on the job and jeopardising the plan. The Security Chief chafes at this and at this outsider's position of power. The War Chief vows to take his complaints to their leader, the War Lord, but first the fugitives must be caught. The War Chief suggests contemptuously that the Security Chief finish interrogating Zoe before she manages to escape too. The Security Chief is furious but says nothing.

A moment later, the Security Chief returns to the security section, horrified to see his guard unconscious on the floor and his prisoner gone...just as the War Chief predicted. He races off to find her.

Meanwhile, Jamie's plan is met with some resistance. He wants to use the machine to travel to the base of operations where this whole place is controlled. He is certain it will return there eventually, with our without the guards. Russell is sceptical and tries to get von Weich to confirm that the machine will actually go back. He, too, believed in the tunnel theory. Von Weich will say nothing to help them, even under threat.

Jamie doesn't want to wait for Russell and starts to board the machine on his own. Lady Jennifer wishes to come too and doesn't take kindly to Jamie's insistence that she stay behind as it's too dangerous for a woman. They spar for a moment, but Russell is the one to stop the argument. He will go with Jamie and Lady Jennifer will stay behind. He has hundreds of wounded men at his HQ. She is a nurse and the only one who can help. Lady Jennifer cannot let go her sense of duty and so agrees to stay. She expresses concern for Lieutenant Carstairs and passes a message via Jamie.

Russell puts a guard on von Weich, authorising him to shoot to kill if necessary, then picks two men to join him and Jamie in the machine. The men look worried but follow their orders. They pile in just as the door starts to close of its own accord. The machine dematerialises. Von Weich watches it go, a smug look on his face...

The Security Chief races to the laboratory and finds the Chief Scientist "cooking" in the processing machine. He releases the unfortunate Scientist and learns of Carstairs' escape at the hands of the devious Doctor. The Security Chief refuses to let the Scientist report this to the War Chief, revealing his deep suspicion of the outside. He tells the Scientist of Zoe's claim of time travel, a technology known only to the War Chief and his people. He notes that they know little of the War Chief except that he betrayed his own people by giving away the secret of time travel. Who knows where his true loyalties lie?

Elsewhere in Central Control, the War Chief receives a report of an incoming travel machine returning from the American Civil War zone. However, its occupants have not followed protocol and called in. It is suspicious, to say the least. The War Chief decides to handle the situation himself, bypassing the Security Chief. He orders all guards to the landing bay immediately.

The Doctor, Zoe, and Carstairs hide out in the landing bay, awaiting the arrival of a machine and the opportunity to steal it. The Doctor is certain he can control it once inside and direct it wherever they'd like. Suddenly an alarm blares and the guards arrive to take up their positions. Zoe surmises it is a welcoming committee for someone important.

A moment later, one of the machines materialises. When its occupants emerge, the truth becomes clear. Jamie is first out, followed by Russell and the others. The guards, unseen, take aim at the new arrivals. It is an ambush!

Security guards drag away the bodies of Jamie, Russell, and the others. A distraught Zoe wants to go and help her friend, but the Doctor knows it's hopeless. They must stay free in order to help him best. They break from their hiding place and disappear back into Central Control. Zoe is worried that Jamie is dead and the Doctor cannot reassure her. He is as worried as she.

He leads the way to the processing room, but does not explain why.

In the security section, the Security Chief admits his suspicions to the Chief Scientist. He believes Zoe's story - told under the influence of the truth machine - that she arrived on this planet in a space/time machine. There are no humans here later than 1917, as more advanced technology would threaten their plans, yet the Doctor knew how to operate the processing machine. He must be from some other time and place. Faced with these facts, the Scientist buys in to the Security Chief's concerns. The Security Chief believes the Doctor was brought here by the War Chief. In fact, he could even be of the same race was the War Chief - a Time Lord.

The Security Chief's mistrust runs deep, but he has very little proof of his allegations. He enlists the aid of the Scientist to obtain that proof. Before he reprocesses the resistance fighters, he is to examine them carefully, checking for signs of any humans who have not been processed in the first place. He is to send anyone he finds directly to the security section of questioning. Of course, all this is to be done without the knowledge of the War Chief.

The Doctor, Zoe, and Carstairs run into a trio of guards outside the main entrance to the processing room. The Doctor is determined to get inside and leads his friends to the room next door, an unguarded wardrobe room. They reach the connecting wall between this and the processing room and the Doctor is quickly engrossed in examining it.

The wall panels are pre-formed plastic, some with bits of metal embedded in them. He surmises that they are held together by an electromagnetic field of some sort. He produces a length of wire and a roll of tape. Zoe cuts off pieces of tape and helps the Doctor attach the wire to one of the wall panels. All of this without a word of explanation.

Next door, the Scientist begins his examination of the newly-captured prisoners. The first man's brain seems normal, a human who has been through the initial processing. It has lapsed, however, and he will have to be re-processed. He moves on to the next person.

The Doctor completes his task, creating a cat's cradle of wiring along the wall panel. He at last explains that he plans to reverse the magnetic field holding the panels together. Zoe suggests using the sonic screwdriver as a power source, but she is very worried that if it works, the entire wall might come crashing down. The Doctor decides they must take that risk.

He activates the sonic screwdriver and a moment later he is able to pull away the wired panel. The rest of the wall stays intact and they can now observe the activity in the processing room. They see Jamie now on the examination table, clearly alive but deeply unconscious. They all breathe a sigh of relief.

The Scientist scans Jamie's brain and is surprised to find that the Security Chief was right. This human was never processed at all.

On the other side of the wall, the Doctor realises what is happening and is quite curious as to what the aliens will do with this knowledge.

The Scientist orders Jamie taken to the security section, but the guards have no time to obey. An alarm heralds the arrival of the War Chief. He is in a foul mood.

The War Chief pelts the Scientist with questions, somehow realising that something is not right. He tries to make up a story to explain why he is examining the humans rather than re-processing them. It is a weak one. He tries to obfuscate when asked why Jamie is being taken for questioning, but cannot do so successfully. In the end, the Scientist is forced to admit that Jamie has never been processed. Oddly, the War Chief accepts this and allows the guards to carry on. Jamie is dragged out. The War Chief turns to go, warning the Scientist to inform him immediately the next time such "unusual developments" occur.

The Scientist breathes a sigh of relief, glad that he is no longer in the middle of his superiors' squabbling. He is a man of science, not politics. He decides to begin the re-processing immediately, starting with Russell.

On the other side of the wall, the Doctor expresses concern over Jamie's fate, but he thinks the lad will be all right for the moment. More pressing is the need to get into the processing room. For that, they'll need Carstairs' muscle.

Carstairs sneaks quietly through the gap in the wall and knocks out the technician on duty. The Doctor then walks boldly up to the Scientist to offer his help once again. The offer is greeted with shock...and not a little fear.

Meanwhile, back in the time zones, the alien Captain von Weich is guarded by one of the resistance men, a nervous young English private called Moor. They are alone in the barn in the American Civil War zone. It has been some time since Russell and the others went away. Von Weich raises the possibility that they'll never return, spooking the young man.

Von Weich asks for some water, but it is really an attempt to distract Moor and escape. But Moore is more capable than he looks. He forces von Weich back to his seat at gunpoint. He gives the prisoner some water, but vows to kill him if he tries anything again.

In the security section, Jamie is under the truth machine. He tells the same story as Zoe, but the Security Chief's questions indicate that he believes the Doctor was sent for by the War Chief. Jamie of course tells him they came here by accident, as always. They are interrupted by the arrival of the War Chief and the questioning ends abruptly. His black mood has become blacker.

The Security Chief tries to make the interrogation look routine, but the War Chief knows it is not. In no mood for games, he reveals that he knows Jamie has never been processed. He demands to know why he was not informed of this fact. The War Chief now has grounds to mistrust everything the Security Chief has told him regarding this new "resistance group" that has invaded Central Control.

Mistrust is now rampant on both sides and neither man seems more committed to this great plan in which they are engaged than to themselves and their own agendas. The War Chief seems to have the upper hand at the moment as it is the Security Chief who is working in secret and withholding facts. The Security Chief has no proof of his allegations and the War Chief warns him that he had better get some if he is planning on going to the War Lord. If he is not absolutely sure of his facts, the War Chief promises to crush him for any attempt at betrayal.

With the Scientist safely out of the way, the Doctor is free to revive Russell and the other soldiers. Russell learns that this odd little man is Jamie's friend the Doctor and he is ready to follow. Now they must find Jamie.

Before they can get moving, a guard passes by the processing room and sees the activity. Carstairs is forced to shoot him. There is now no time to lose. Zoe and the resistance men escape through the gap in the wall, but the Doctor hesitates. He is trying to remove the processing machine from its stand but it is stuck. Carstairs shoots another guard as he approaches. It is getting too hot to stay here. He forces the Doctor to leave the machine behind and escape through the gap.

An alarm sounds and more guards take up position outside the processing room. They do not go in, though, not wanting to be shot. They believe that they have trapped the fugitives in the room, not realising that they are already long gone.

Russell learns that they are in the HQ of the people running "this whole disgraceful business" and is ready to fight his way out, taking as many of the aliens with him as he can. The Doctor talks him out of it, telling him he's got a better idea. He plans to return to the time zones and to use Zoe's remarkable memory to locate all the resistance leaders she learned of. Once combined into a single fighting force - no easy task, to be sure - they can fight against the aliens. First they need to find Jamie and then get to the landing bay. With the guards now on alert, they'll need some sort of disguise.

Back in the American Civil War zone, von Weich tries again to gain Moor's confidence. The lad is wary, but he doesn't want to mistreat his prisoner. He helps to fetch von Weich's monocle as the prisoner's hands are tied. A tragic mistake. Using the monocle, von Weich asserts his mental control over Moor's mind. It takes some work, but soon Moor has forgotten all about "the resistance" and is back in the British Army, 1871. Von Weich is no longer his prisoner but his commanding officer.

Back at the processing room, the War Chief and the Security Chief arrive outside. On the Security Chief's order, the guards burst in. All are shocked to find the room empty. The Security Chief - nearly consumed by his suspicions - believes they escaped by use of a space/time machine. The War Chief, however, finds the loose wall panel and crushes the Security Chief's wild theory. He urges the Security Chief to get his guards to the landing bay, the obvious destination for the fugitives. He can only hope they'll reach it in time.

In the security section, Jamie awakes to see a soldier in a horrific gas mask looming over him. Luckily, it is just the Doctor in disguise. They've brought a military overcoat for him as well. Soon the group is all together and marching off toward the landing bay.

They overpower the technician on duty and the Doctor examines the controls for the space/time machines. They are set upon by security guards, but the Doctor manages to hold most of them off with a force field. The two who do get through are dealt with by Jamie, Russell, and Carstairs.

The Doctor sets the controls on the main board to send the machine back to the American Civil War zone. Zoe remarks how easily the Doctor learned the controls but he brushes it off. Only Zoe, Russell, and his men are going back in the machine. The Doctor cannot leave without the processing machine and Jamie and Carstairs decide to stay behind to help.

The Doctor sends the others off, then releases the force field. By the time the guards get inside, their quarry is nowhere to be seen. They race out of the landing bay in search of them. Once they are gone, the Doctor and his friends emerge from hiding and head off in the opposite direction.

Back at the American Civil War zone, von Weich uses his influence over Moor to free himself, but before Moor can hand over his rifle, the air is filled with the grinding engine noise of a time/space machine. Russell emerges and von Weich urges Moor to shoot the newcomer. Momentarily confused, Moore hesitates. Russell takes the initiative and there is a struggle. Both men are disarmed and they fight hand-to-hand. Russell, a much larger and more experienced soldier, makes short work of Moor, dropping him, dazed, in a corner.

Von Weich has recovered one of the guns and tries to force Russell back into the machine. He refuses and von Weich raises his gun to fire. A shot rings out, but it is not from von Weich's gun. It is from Moor's. He has shaken off the mental control and acted against the real enemy. Russell is glad for the boy's quick response, but even knowing he's done the right thing doesn't make young Moor feel better for his act of murder.

Back at Central Control, the Doctor, Jamie, and Carstairs reach the processing room unseen. The Doctor goes straight for the machine.

The War Chief chides the Security Chief for his continued failure to catch the Doctor and his friends. The Security Chief takes his words as proof that the War Chief knows the Doctor, but the War Chief counters easily. The Security Chief's logic is slipping in his misguided zeal to prove a conspiracy. The War Chief only hopes he's sorted it all out before the War Lord arrives. The Security Chief assures him the fugitives will be caught.

The Doctor loads up the processing machine in a military duffel bag and is ready to go. On the way, he grabs some gas cylinders he spies in the laboratory. As they leave, they do not notice the Chief Scientist, back up and about. He sees them and realises his precious processing machine has been taken.

At the landing bay, the Doctor uses a gas cylinder to scatter the technicians and guards. He and his friends get into a time/space machine and take off.

However, the machine's dematerialisation is suddenly halted from outside. The Doctor locks the doors to keep them safe, but he will have to work hard to override the master control. He remarks that the controls are "a slightly different design to the TARDIS". The machine is even impregnable to outside attack, just like the TARDIS.

Outside, the Security Chief and the War Chief head a squad of guards, alerted to the fugitives' presence by the Scientist. The Security Chief issues an ultimatum to the fugitives via intercom: come out and their lives will be spared. However, he has no plan for actually getting them out, a fact the War Chief points out. They could stay in there a very long time indeed.

Taking matters into his own hands, the War Chief decides on a plan to force them out. He activates the dimensional controls...

Inside, the Doctor works at the controls but is still having no luck. He is certain they are safe but Carstairs proves him wrong. He is first to notice that the walls and ceiling are closing in on them. The interior dimensions of the machine are being shrunk.

The walls and ceiling of the time/space machine shrink down inexorably on the Doctor, Jamie, and Lt. Carstairs. They are as flat as they can be on the floor, but the dimensions inside the box continue to shrink. The War Chief's voice blares all round them, counting down the seconds before they are crushed to death. The Doctor decides there is nothing else for it but to give up and come out.

Just before the War Chief reduces the inner dimensions to zero, the door of the machine opens and the Doctor comes out, waving his white handkerchief as a flag of truce. The others stay inside and the War Chief is wary. He wants them all out. Now. The Doctor refuses and suddenly produces another gas cylinder. The room fills with thick, acrid smoke. The guards cannot see to fire or move to stop him. Using His "flag of truce" to cover his nose and mouth, the Doctor moves easily. He restores the dimensions inside the machine and steals several master control rods from the control board before scurrying back inside.

The door closes and they are gone. The Security Chief is furious. The War Chief is angry as well, but also impressed at the Doctor's ingenuity. He knew just which controls to steal and how to stop them bringing him back. The Security Chief issues an order to alert all time zones of the fugitives. The War Chief thinks they'll make for the 1917 zone, but does not say why. With the circuits the Doctor took, he can now guide the machine to any time zone.

Inside the machine, the Doctor decides to avoid the 1917 zone for the moment. He wants to get there as that's where he's arranged to meet Zoe, but not directly. It will call attention to them. He intends to land in one of the nearby zones and travel to 1917 on foot.

Back at Central Control, the Security Chief and the War Chief set about trying to trace the space/time machine. The War Chief gives the machines a name - SIDRATs - The origin and meaning of the name is known only to him, not the aliens to whom he works. This fact only exacerbates the tension between the War Chief and the Security Chief. However, their bickering is interrupted by an alarm sound. It announces the imminent arrival of the War Lord from home planet. He is the leader of the aliens and the ultimate architect of this undertaking, these war games.

The War Chief and Security Chief spar as to who will go and receive the War Lord. The War Chief wins out, noting that the Security Chief has a serious security breach to deal with. The Security Chief stays behind rather miserably, knowing that a large part of the blame for recent events will fall on him, no matter how is at fault. He barks an order to the technicians watching him innocently. Soon they shall know where the SIDRAT has landed.

The Doctor, Jamie, and Carstairs rest a moment on the floor of the machine as it takes its time in finding a landing place. The Doctor cannot really say where they are going to land - just like in the TARDIS - but they'll soon know. The engine noise fills the air as they start to materialise. The Doctor gathers up the precious processing machine and warns his friends to be careful once they go outside. He is certain the soldiers will be on the lookout for them wherever they have arrived.

In Central Control, the SIDRAT's location is pinpointed - Roman zone, sector 5. An alert is issued and soldiers will soon surround the area. He works unaware that the War Lord is watching him. The War Lord is a small and seemingly quiet man. He looks unassuming and speaks softly. His eyes blaze with a keen intelligence and his speech reflects a man who chooses his words with care. He looks upon the Security Chief with some disdain. Clearly the rumours of trouble that he's heard are true.

The Security Chief stumbles over a response, trying to hide the magnitude of the problem. The War Chief is glad to see the Security Chief getting the brunt of the War Lord's displeasure, but it is his turn to squirm soon enough. He is forced to admit the infiltration of Central Control by "resistance members" and the theft of the processing machine. The War Lord nearly loses his cool at this news, shouting angrily. The Security Chief steps in to say he has everything under control. A report has just come in from the Roman zone.

Out in that zone, the Doctor, Jamie, and Carstairs try to orient themselves with their map, making sure they're still walking toward the 1917 zone. They get their answer when they are suddenly attacked by a group of Roman soldiers. It is the same place they were attacked before. The Doctor and his friends pick up their pace toward the time zone barrier they know is nearby.

At Central Control, the War Chief monitors this movement, knowing that the fugitives will get away again. The processed Romans cannot pass through the barrier. The Security Chief suggests using security guards but the War Chief worries that their presence will strain the credulity of the processed humans and upset the operation. They dissolve into bickering.

The Security Chief decides to reveal the extent of his mistrust of the War Chief. He admits that he believes the Doctor is in league with the War Chief. He knows their technology and has a space/time machine of his own. The War Chief has given this technology to the War Lord and his people for the purposes of these war games but has not shown them how to construct such machines. He believes that the War Chief has summoned the Doctor here for some treacherous reason yet unknown.

The War Chief knows there is no proof to this story, but he cannot help but worry what the War Lord may think. Their bickering finally gets on the nerves of the War Lord, who has seemed not to be listening until now. He silences them both sternly and warns them that their inability to work together will not be allowed to jeopardise the major plan. They must work together or they will be replaced.

The Doctor and his friends stop for a moment to rest inside the misty time zone barrier. They are safe here from the Romans. Carstairs has no trouble traversing the barrier, indicating that his processing has been completely removed. The Doctor leads the way out.

They reappear on a hillside in no-man's land, 1917. Bombs explode all round them. The landscape is very familiar. They don't wait around, moving off quickly. Unbeknownst to them, their arrival has been noted...by a party of British soldiers.

They report their information to the chateau and General Smythe. He has been waiting for the Doctor to return and he is ready for them. There is a machine gun emplacement right near their location. Smythe will deal with the Doctor once and for all.

The Doctor and his friends keep moving and are soon in range of the machine gunners. Bullets begin whizzing around them in rapid fire. The three men take cover. They're safe, but pinned down. Luckily, rescue is at hand. Zoe and several resistance members have been waiting for the Doctor's arrival as well. They are able to sneak up behind the machine gun emplacement and take out both gunners. But a new problem arises. A troop of British soldiers descends upon their hiding place and takes the Doctor, Jamie, and Carstairs prisoner.

Zoe and her resistance friends must follow them to await another chance of rescue.

The Doctor and the others are brought before a very angry General Smythe. The trouble and embarrassment the Doctor has caused him weighs heavily. The death sentence hanging over the Doctor's head from his court martial will be carried out. The other two prisoners will be put to work in the most dangerous sector of the fighting...after some mental processing.

Carstairs tries appealing to Smythe's Sergeant-Major, telling him the truth about all that's going on here. Smythe counters with his own mind control, reasserting command over the soldier. He says Carstairs is delirious and the Sergeant-Major accepts it. He is ordered to prepare a firing squad for the Doctor.

The Doctor reminds Smythe that his superiors will want him kept alive for questioning. Smythe knows this, but out of sheer malicious revenge, he decides to ignore the order. Clearly he has not received orders from Central Control regarding the Doctor. With great glee, he orders the Doctor taken outside to be shot. Carstairs and Jamie are held captive here.

Smythe goes into his room and reports the capture of the prisoners via the video communications unit. He is certain his superiors will be pleased and he is right. The War Chief congratulates him. Smythe reports with mock regret that the Doctor is already dead - "shot while trying to escape". The War Chief becomes angry, realising that Smythe did not receive the urgent message regarding these fugitives. They were to be captured alive and the vital processing machine recovered. Smythe can feel his victory slipping away as the War Chief orders him to find the machine the Doctor stole.

Horrified, Smythe questions Jamie and Carstairs about the machine. Thinking quickly, Carstairs says it's hidden and only the Doctor knows where. Kill him and it will never be found. Smythe races to the window as he hears the Sergeant-Major prepare the firing squad. There is little he can do as the men take aim and prepare to fire.

However, as before, shots ring out before the order is given. Shots from resistance members at the chateau. A gun battle breaks out in the yard as Russell and his men flood the place. They burst into the chateau and Smythe flees into his room, locking the door. Jamie and Carstairs are distracted when the Doctor arrives, alive and well, and forget about Smythe. The Doctor is horrified to learn that Smythe is alone in his room. He'll be able to call his superiors for help!

As Russell and his men batter at the locked door, Smythe begs the War Chief to send help immediately. Even if he wanted to, he could not as the lost control rods have shut down the SIDRATs. New ones are being prepared but that will take time. But the War Chief is not really inclined to help the hapless Smythe as he has failed to recover the processing machine.

The War Chief orders Smythe to "de-activate the area control", his voice rising in urgency. Smythe opens a credenza in his room to reveal some very sophisticated electronic equipment. He starts to adjust it when Russell finally batters the door down. There is a brief exchange of gunfire and Smythe is killed, long before he could carry out his superior's orders.

The Doctor and Zoe examine the controls. Zoe turns off the video link but not before they are both seen by those receiving at the other end.

The War Chief now knows that Smythe was lying and that the Doctor is still alive. He and his friends now have control of the chateau and all the technology within. It is clear that the Doctor understands the technology and that makes him even more dangerous. The War Lord is livid, but all is not lost. If a large group of resistance members are all in one place, it will be much easier to wipe them out. However, he dismisses the plans of his lieutenants. Neither security guards nor an artillery barrage will work. Both will destroy all that they've worked for. He suggests a conventional military attack using processed humans - a pincer movement with the chateau at the centre.

The Doctor doesn't have long to examine the electronics in Smythe's room. He receives word that the chateau is surrounded by soldiers, far more of them than the resistance can defeat. Already there is gunfire all round. Carstairs and Russell think they can hold out a while longer and the Doctor urges them to do so. He thinks he has a solution to all of their problems, but it will take some time.

He has determined that the equipment in Smythe's room controls the time zone barriers. With Zoe's help, he hopes to dismantle it and learn how it works. They set to work as the gunfire outside increases.

At Central Control, the War Chief oversees the pincer movement. Both sides are actually involved, with the British attacking from one side, the Germans from another. The Security Chief is concerned that it is taking too long, but the War Chief is confident. Exposing his suspicions once again, the Security Chief wonders whether the War Chief will allow the Doctor to be killed along with all the others. He assures him that the Doctor will die like all the others. He himself will see to that.

The battle for the chateau is going badly for the resistance. Soldiers are nearly upon them. One even manages to toss a grenade inside. Russell and Jamie take care of both explosive and soldier, but more will be coming. Carstairs suggests trying to get the Doctor and Zoe out before this happens, but the Doctor refuses to go. He thinks he has achieved his goal.

He switches on the reconfigured equipment and a silence engulfs the chateau. All the gunfire outside stops. There is no sound outside at all and a misty void can be seen out the window. The Doctor has managed to set up a time zone barrier all round the chateau. Now the processed soldiers cannot get in, yet the de-processed resistance members can come and go at will. The Doctor - not to mention the soldiers - is very pleased.

With a safe base of operations, the Doctor turns his attention to the next step. He eyes a French soldier recovering in a chair. He is a processed soldier who was captured while attacking the chateau. This is just the specimen the Doctor needs.

The Security Chief and the War Chief trade recriminations over the failed attack, but there is no escaping the facts: the War Chief failed. But the War Lord points out that the Security Chief has also failed to capture the Doctor several times as well. He himself will now take personal charge. He lays out his plans...

At the chateau, the Doctor uses the stolen machine to de-process the French soldier. It appears to be successful, although the language barrier is a problem. Using his rudimentary knowledge of French, Carstairs determines that the de-processing worked. The young soldier knows he is no longer fighting World War I, but it will take some doing to explain the resistance to him and what has happened to him. Carstairs takes him off to try.

Russell is pleased to know that they can now de-process the soldiers and gain new recruits for the resistance, but the process is too slow. The Doctor thinks he can speed it up with more equipment, but there's no time for him to elaborate on his plan. The sound of a time/space machine materialising fills the air.

From the machine, a squad of security guards appears, firing their futuristic weapons. The resistance soldiers are no match for the energy rays and fall backward, dead. The Security Chief appears and orders the Doctor taken prisoner. Russell and his men hold their fire for fear of hitting the Doctor. He is hauled into the SIDRAT and the Security Chief recovers the precious processing machine.

The SIDRAT time/space machine returns to Central Control after its successful commando raid. The Doctor is lead off by guards for questioning whilst the Security Chief examines his prize - the mental processing machine.

Back at the chateau, the Doctor's friends cast about for a plan of action, even as they lament the loss of the Doctor. Jamie wants to try and summon another machine, but it will likely be full of guards. Carstairs suggests trying to blow up the machine when it lands, but that risks destroying the time zone barrier equipment. All they can do is set up a machine gunner in the room in case another machine arrives.

Jamie is livid. None of this will help them get the Doctor back, and that is his main priority.

Meanwhile, the Security Chief receives congratulations from the War Lord on his success. The Security Chief is to go to the security section and question the Doctor, but first he must return the processing machine to the Chief Scientist. He will take it back to home planet to have it mass produced.

Once the Security Chief is gone, the War Chief asks to assist in the Doctor's interrogation. He says the Doctor is no ordinary resistance leader and will need "special treatment" to make him talk. The War Lord agrees to this, confident that his plans for the war games are now back on track.

A short time later, the Security Chief interrogates the Doctor using the truth machine. He is getting nowhere and the Doctor says nothing. The Security Chief's questions have nothing at all to do with the resistance. Instead, he asks about the War Chief. He is more convinced than ever that the two men are of the same race - the Time Lords - and that Doctor's arrival here is part of a plot to betray the War Lord and his people to the Time Lords. When the Doctor doesn't answer, the angry Security Chief turns up the power on the mind-probing truth machine, threatening to destroy the Doctor's mind if he doesn't co-operate.

Russell gets two men set up with a machine gun to await the arrival of the SIDRAT, then reports to Carstairs, now the de facto leader of this group. Carstairs turns his mind back to the Doctor's original plan - to find, contact, and unite all the extant resistance groups into one large army. He decides that they must carry on, using Zoe's photographic memory to provide names and locations of the resistance leaders. Russell is particularly keen on contacting one Arturo Villar from the Mexican Civil War zone. His band of resistance fighters is the largest, bandits for the most part. They would be a welcome addition to any united force.

Suddenly the grinding engine noise of a SIDRAT issues from the other room. A new attack. The machine gun fire that greets them gives the security guards pause, but they can still fire their energy weapons from the safety of the machine's doorway. Carstairs puts paid to this by lobbing a grenade into the open door. It explodes and the machine dematerialises. The guards won't be returning any time soon. Just in case, Carstairs orders another machine gunner put in place.

Russell knows time is short. He makes ready to go out and contact the resistance leaders in Zoe's memory. He places Jamie in charge of the forces remaining at the chateau. The young lad is well-pleased but a bit nervous about the responsibility.

Back at Central Control, the Security Chief cranks up the power on the truth machine even further, bearing down on the Doctor. At this rate, his mind will only last another 15 minutes. However, the session is interrupted by the (for once) stealthy arrival of the War Chief. The Security Chief breaks off the interrogation when the War Chief tells him with great confidence that the Doctor will never talk. The War Chief admits that he and the Doctor are of the same race - the Time Lords. The truth machine will not work on them.

The Security Chief is triumphal, thinking that all his suspicions about the War Chief have been proved correct, but the War Chief is strangely calm. He knows the Doctor and he knows that only he can make the Doctor talk. He pulls rank and has the prisoner released into his custody. They will talk alone...in the war room. Security guards take him away as the Security Chief fumes.

The Security Chief is almost as furious at his failure as by the War Chief's usurpation of his authority. As the War Chief goes off, the Security Chief sends an urgent message to the War Lord...

The War Chief clears the war room of all personnel and guards. It is just him and the Doctor now. All pretense is dropped and the two Time Lords speak frankly. The War Chief knows the Doctor has changed appearance and remembers him from before. He even knows of the TARDIS. There is an accusatory tone in his voice as he relates these facts. The Doctor responds that he "had every right to leave" their home world. The War Chief reveals that he knows the Doctor stole his TARDIS and left the Time Lords and he tries to draw a parallel between them. The Doctor refuses to accept this. He will not explain his reason for leaving their society but he says that the War Chief's reason is only too obvious: power.

The Doctor knows all about the kidnapping of soldiers from Earth and how they are brainwashed and made to fight here on this planet. He is disgusted by the wholesale slaughter. The War Chief, by way of justification, explains the goal behind the plan. The War Lord and his people air to conquer the galaxy and subjugate 1000 inhabited worlds. They are using the war games to find the best soldiers among the human race. They will make up the conquering army. The War Chief and his alien allies believe humans are the most vicious species of all and that this plan puts their savagery to some purpose. Once the galaxy is subdued, it will be at peace at last. It is clear that the War Chief sees himself as the bearer of tranquillity, even though it must be achieved by force, and he wants the Doctor's help in this pursuit.

Night falls at the chateau and everyone sleeps. In the darkness and silence, a group of men makes its way inside, knocking out the resistance soldiers with great stealth. Their leader, a big man with a moustache and a sombrero, steals into the main room and wakes Zoe at gunpoint. This is Arturo Villar, and he demands to speak with Russell.

Zoe tries to take charge of the situation but Villar is wary and cunning. His men surround the chateau for fear of a trap, but he is interested enough in the message from Russell to want to see him. He cuts off Zoe's protests, uninterested in listening to a woman.

Zoe finds and wakes Jamie to tell him what's happened. Russell has still not returned and they must do something themselves to try and win Villar over to their side. She knows that the chauvinistic bandit won't listen to her, but she's got a plan...

A few moments later, Zoe returns to Villar with the news that Russell is not here. Villar starts to leave, but she stops him by introducing the group's "other leader". Villar stays, but he is unprepared for what he sees next. A young Scots lad appears, kitted out in a mishmash of military paraphernalia including a bullet-laden bandolier, a hat, and hand grenades. James Robert McCrimmon tries to look imposing and leader-ish and somehow manages to pull it off. Villar is pleased to meet their "leader".

The cautious bandit has some questions, though, before he'll agree to join this group. Jamie tries to explain the plan to unify the resistance fighters and attack the aliens who brought them all here, but finds himself tongue-tied. Zoe helps out, confusing Villar as to just who is in charge here. But the message they present is clear - alone, Villar and his men are hunted fugitives with no chance of success. Together, they might just be able to get home. It is the only possible way. Villar is still wary but decides to stay for the meeting of the other resistance leaders.

Back at Central Control, the War Chief continues outlining their glorious plan, insisting that peace will reign under one united galactic empire. The Doctor is of course disgusted by every word, and especially by the fact that the War Chief has given these aliens "our science" with which to carry out their plans. That explains how the Doctor so easily understood the SIDRATs and the processing machines. He is adamantly op