The Daleks are interrupted by a coded message from the Emperor instructing them to bring the Doctor to Skaro alive. By now the meteor storm has passed, so the Daleks continue their course back to their home planet. They order the Doctor to explain to their scientist how the TARDIS works, but he refuses to co-operate, knowing they have orders not to kill him. Instead, they threaten to kill his companions one by one, starting with Crystal, so he reluctantly agrees. He insists that he won’t help unless he can see that his friends are safe, so the senior Dalek allows them all to enter the TARDIS together.
Inside the TARDIS, the Doctor is horrified to see that the Dalek scientist has already started to dismantle the console to discover its secrets. He warns them of the harm they could do with their indiscriminate tinkering and says the power source of the TARDIS could reduce their entire battle cruiser to atomic particles. He accuses the Dalek scientist of being ambitious and the senior Dalek disciplines the scientist for his insubordination and orders him to return to the flight deck of their own ship. The Doctor says he’ll have to repair the damage before he can show them anything and points to a power cable with a frayed end that’s been broken off. As the senior Dalek moves closer to examine it, the Doctor thrusts the cable at him and he’s hit with a terrific burst of electricity. Jason and Crystal push the Dalek out through the doors and the TARDIS dematerialises. Unfortunately the Doctor wasn’t bluffing when he said the ship is in a dangerous condition and it’ll take time to fix the damage. He switches on the EDS - the Emergency Displacement System - which will automatically take them as far from the source of danger as possible and land them somewhere completely safe. Crystal decides to take a little nap while the Doctor asks Zog to help him sort through the toolbox.
On Skaro, Karl tells the Emperor Dalek that reports are coming in that the Doctor has escaped again. The Emperor orders all Dalek patrols to find the Doctor and bring him here alive. The Cyber-leader believes Karl’s plan has failed, but Karl insists the fault wasn’t his. The mercenary can’t understand why the Doctor is so important to the Daleks as they have the American envoy and the peace conference is already endangered, but the Emperor orders him not to question their orders.
The TARDIS materialises on an alien planet, but the Doctor has barely had time to start the repairs as there‘s a limit to what he can do while in flight. Crystal returns from taking a rest and asks where they are, but the Doctor has no idea where or when they’ve landed as most of the instruments are still on the blink. However, the one fact they can rely on is that they’ve arrived somewhere safe. Crystal decides to go out and explore, but she leaves before the Doctor can tell her to treat all alien planets with respect.
The moment Crystal steps outside the TARDIS she finds herself floating high up into the air. Jason rushes to help her and she tells him she only took one step and ended up bouncing around the desert like a ping-pong ball. Jason encourages her to move more slowly and eventually her feet come back down to the ground. They both sit down on a nearby rock and admire the beautiful landscape with all the different coloured sands. Jason tells her it’s not the only thing that‘s beautiful and then they begin to sing the duet “Sky High“. Jason realises he’s starting to fall in love with Crystal and he tells her that travelling with the Doctor can sometimes have its advantages. They decide to head back for the ship.
As they enter the TARDIS, the Doctor says he’s ready to take off again. Crystal excitedly tells him about their experiences outside and he explains that it’s because they’re on a low gravity planet. He needs to take the ship on another test run, but he’ll use the Emergency Displacement System again so even though he has no idea where they’ll land, he’s sure it’ll be somewhere perfectly safe. The TARDIS materialises again and the Doctor’s best guess is that they’re somewhere on Earth and that they’ve gone back in time rather than forward. The two youngsters go outside to explore while the Doctor and Zog return to their repairs. On further examination, the Doctor confirms that they are indeed on Earth and he eventually narrows it down to France. He checks the time period and discovers to his horror that they’ve landed in 1789 - right in the middle of the French Revolution. He’s brought poor Jason back to precisely the time and place where the people wanted to cut off his head…
Outside, Jason is starting to think there’s something terribly familiar about this place. Then, just ahead of them in the town square, they see something he recognises only too well - Madame Guillotine!!! From out of nowhere, revolutionary guards appear and grab Jason. They taunt the young man for not getting very far after escaping their clutches just a few short minutes ago and are delighted that the crowd of onlookers won’t be disappointed after all. Jason is dragged away and Crystal is left alone, powerless to help - but then she finds herself standing next to Zog, who’s wearing a cloak and a revolutionary cap. They watch as Jason is strapped to the guillotine, but they notice the Doctor is approaching the crowd, disguised as an old crone. The Doctor giggles at the fate of the handsome young Marquis and asks the executioner for permission to take a lock of his hair as a memento. The guard agrees, although he suggests she might just as well wait a while and then she can take the whole head. The Doctor produces a knife and climbs up onto the stage, but before anyone can stop him he cuts right through the ropes around Jason’s hands. Zog rushes forward and throws a number of smoke grenades which explode instantly. The whole area is covered with a thick fog and the guards mill around in confusion. The Doctor gathers together his companions and they all race back to the TARDIS…
Inside the ship, the Doctor apologises to Jason for sending him into such danger, but his friend is just relieved to have escaped the ordeal a second time. The Doctor is reluctant to take off again until he’s worked out what’s wrong with the Emergency Displacement System and Jason tells him it’s almost as if the device was working backwards. The Doctor checks and discovers he’s right - the Dalek scientist must have reversed the linearity of the proton flow, which threw the EDS into reverse, making it seek danger rather than avoid it. The problem was so elementary it baffled the Doctor completely, but now he knows what’s wrong, it should be easy to fix. As he and Zog get to work, Jason reminds them they don’t have much time left before the peace conference on Earth begins. They still haven’t rescued the envoy or discovered how the Daleks plan to blow up the conference, so the Doctor decides to go back to Madame Delilah’s. He’s sure he can soon clear up the rumours Karl spread about him having a price on his head and he’s confident he was starting to win Delilah over.
The TARDIS lands back at the Bar Galactica, but everything is dark and quiet. Crystal wonders if the bar is closed for the night, but Jason thinks it’s more likely the mercenaries are sleeping off their hangovers. They go to Madame Delilah’s private booth and find her there alone with a bottle of champagne. The Doctor tells her he wants to continue their rudely interrupted conversation, but Delilah is more concerned with the fact that Zog seems to have abandoned working for her in favour of the Doctor. It confirms what she suspected - the Doctor isn’t really a mercenary at all. She’s been making enquiries about him and has discovered he’s a Time Lord, one of the aristocratic elite of the cosmos. He insists that he’s a renegade and says he’s come her to ask for her help in saving a far-away planet. Delilah says there’s no profit in that for her, whereas she can gain a million credits if she hands him over. She knows he’s not the criminal mastermind Karl claimed, but she’s discovered the bounty on his head is actually real if she hands him over alive to the Daleks! The Doctor turns to leave, but Delilah pulls a dainty little jewelled blaster on him and reminds him of the mercenary motto “business is business”.
While they’ve been talking, the Doctor has failed to notice that Delilah’s men have surrounded them. The bar obviously wasn’t empty after all. Karl arrives with two Daleks and tells Delilah that he’ll take over now, but she refuses to hand over the Doctor until she gets paid. Karl tries to assure her she’ll get her money later, but she believes working for the Daleks has made him forget the rules of being a mercenary. The Daleks intervene and state that there’ll be no bounty as they’ll tell the Emperor it was them, not the mercenaries, who captured the Doctor. Karl becomes angry at their attempts to cheat a fellow mercenary and tries to convince them it’ll be in their interests to pay up. The Daleks still refuse to co-operate, so Delilah orders the other mercenaries to turn on them. A massive fight begins and the Doctor urges his companions to use the blaster fire as cover while they race back to the TARDIS.
From inside the doorway, the Doctor watches as the mercenaries are slaughtered, but as the Daleks turn their attention to him, Delilah steps in the way to protect him. She screams as she’s cut down by a Dalek blaster. Karl is so enraged he physically wrenches off the top casing of the Dalek and blasts the creature inside. The other Daleks turn to exterminate Karl, so the Doctor throws him a fire extinguisher and he uses the freezing cold carbon dioxide to disable them before they can open fire. Karl is grateful to the Doctor as he could‘ve used the opportunity to escape, and in return the Doctor is thankful that Karl didn’t stick with the Daleks while they were winning.
The Doctor attends to the dying Delilah and she tells him it was a pleasure to meet him and it‘s a pity they can‘t pursue their friendship. The Doctor is honoured and says he owes her his life. She tells Karl that the Daleks tried to cheat them and urges him not to let them get away with it. As she dies, the Doctor tells Karl it’s time he decided whether he wants to pursue revenge or profit.
Later, the TARDIS materialises in the prison area on Skaro and the Daleks prepare to take the Doctor prisoner the moment he emerges from the ship - but to their surprise, the figure that emerges from the TARDIS is not the Doctor, but Karl…and he’s accompanied by another Dalek. Karl announces that they’ve captured the Doctor and his companions, then he orders the Doctor, Jason and Crystal to step outside. Then Karl tells them the Emperor has issued new orders and their prisoners are to be taken to the high security area. The Daleks realise one of the Dalek patrol assigned to the mission is missing and the Dalek accompanying Karl tells them it was destroyed during the battle. The other Daleks leave and the Doctor’s party breathe a huge sigh of relief. Inside Karl’s Dalek is Zog and they check on him to make sure he’s still okay before resealing the casing. Crystal asks the Doctor how he was able to make Zog’s Dalek talk and he tells her he used ventriloquism and a small device that makes his voice sound like a Dalek. Karl says they need to hurry as time is running out. The Doctor tries to persuade Crystal to stay behind in the TARDIS where she’ll be safe, but she insists on seeing things through to the end.
In the main HQ, the Emperor learns that the Dalek patrol who accompanied Karl to the mercenary bar has failed to report in. He orders them to send another patrol to investigate as without the Doctor, their plan cannot succeed. The Cyber-leader questions whether the Doctor is likely to come here, but the Emperor is certain he’s already on Skaro as he knows the Doctor would never return to Earth without the envoy.
In the high security area, the Doctor locates the kidnapped envoy trapped within a light cage. He seems to be unconscious and there’s a weird glow all around him which the Doctor identifies as a laser wall. He tries to break through it with the sonic screwdriver, but it’s hopeless. He realises the reason there are no Dalek guards here is because they don’t need them. Karl suggests contacting some of the other mercenaries who are still on Skaro in case they can help, but the Doctor says it would just be a useless waste of their lives. Crystal finds a control console with recording and monitoring equipment and the Doctor guesses they’ve been interrogating the envoy. They play back a recording in which the envoy refuses to answer the Daleks’ questions and insists on being returned to Earth. The laser wall is probably controlled from the Emperor’s throne room, so Jason volunteers to sneak in and switch it off, but the Doctor warns him the base is full of armed and angry Daleks. Instead, he proposes something difficult and dangerous but it’ll mean he has to return to the TARDIS. Jason decides to stay here with the Zog Dalek to keep an eye on things and Karl offers to find the rest of his men and win them over, so the group separates. Once they’re alone, Jason tells Zog he’ll have a quick scout around, just in case the Doctor was wrong about the guards.
The Daleks report back to the Emperor with news that the second patrol sent to Madame Delilah’s have found the missing Daleks - both were dead, as were Delilah and many of the mercenaries. One of the dead Daleks had been removed from its casing. Also, Karl recently returned to Skaro accompanied by a Dalek and the Doctor’s group as prisoners, but no prisoners have been handed to the security section. It’s now clear that Karl is a traitor and the Doctor’s group are loose on the base, accompanied by an impostor Dalek. Instructions are given for all Daleks to be alerted to search the security area…
The Doctor and Crystal take a different route back to the TARDIS to avoid the Dalek patrols. They find themselves in a storage area filled with boxes and crates. They hear two Daleks outside the storage room, planning to search inside so they quickly hide inside empty crates, but Crystal is immediately spotted and the Daleks lift the crate on a hoist into mid-air. Then the Daleks open fire and the crate explodes. Incredibly, the crate turns out to be empty, so the Daleks begin searching elsewhere for the escaped fugitive. Once they’ve gone, the Doctor helps Crystal out from a different crate. She asks him how he did that and he explains that it was a simple illusion, adding that Harry Houdini himself studied under him! Jason arrives and the Doctor demands to know what he’s doing here. They hear another announcement about the impostor Dalek. An order is given for all lone Daleks to be challenged for their recognition signal and any that fail to give one will be exterminated. Jason agrees to return to Zog while the Doctor and Crystal continue on their way to the TARDIS.
The Doctor asks Crystal to wait outside the TARDIS as he’s about to attempt a rather dangerous experiment. He goes inside and the ship begins glowing and vibrating. The Doctor emerges and Crystal says she thought it was going to explode. He doesn’t know whether his experiment has worked yet, but says they’ll soon find out…
Jason returns to the high security area and finds Zog waiting patiently inside the Dalek casing. Suddenly more Daleks arrive and, seeing the lone Dalek, they approach it and challenge it for its recognition signal. There’s no response, so a final warning is given. When the Daleks realise they’re facing the impostor, they open fire and the casing is completely destroyed. Jason is horrified. The Daleks resume their hunt for the other fugitives, then the Doctor and Crystal arrive. Jason tells them what happened, but as they mourn the loss of their friend, they’re amazed to find Zog hiding nearby. The Doctor speaks to Zog and discovers he got nervous waiting on his own, so he got out and hid. Then the Doctor reveals that he’s about to create a time tunnel, the only thing that can get them through the laser barrier imprisoning the envoy. He shows them a beautiful glowing crystal pendant and says he filled it with concentrated temporal energy from the TARDIS. He warns them they won’t have long, so he asks Crystal to swing the pendant round in a giant circle while he and Jason go inside the laser cell to bring the envoy out. As the pendant swings faster and faster, a time tunnel forms right through into the cell. They manage to release the envoy just in time and the Doctor congratulates everyone.
In the Dalek HQ, news arrives that the envoy has been released from his cell. The Emperor Dalek gives orders for the Doctor to be captured…
Eventually the Doctor, Jason, Crystal, Zog and the American envoy arrive at the TARDIS - but before they can enter, Karl and his mercenaries emerge from their hiding place. It’s a trap and Karl also has the Daleks with him. He confesses that he was caught by the Daleks, so he came to an arrangement with them - a million credit bounty in return for helping to capture the Doctor alive. The Doctor isn’t surprised. For a moment he thought Karl might be something more, but in fact he’s just a mere mercenary after all.
The Doctor’s group are returned to the high security area, only this time they’re the prisoners and there are Dalek guards all around them. Crystal is resigned to their fate, but the Doctor is surprisingly confident. He tells them things are never hopeless and he remembers saying something similar to Winston Churchill once, just after Dunkirk. Churchill was in the dumps, but the Doctor managed to persuade him the British public were about to face their finest hour. The Doctor tells his friends he’s faced lots of darkest hours like this one, but he’s learned there’s always a dawn afterwards. Then a Dalek arrives and tells the Doctor he’s been summoned to face the Emperor.
The Emperor Dalek tells the Doctor this is his ultimate defeat, but this just makes the Doctor laugh. He knows the Daleks don’t want him dead for some reason but the Emperor merely says this would be too easy. Instead, they plan to force him to watch the destruction of his beloved Earth. The Doctor believes the Daleks are rankled because there have been so many failed attempts to conquer that planet, but the Emperor says he’ll only understand the truth when it’s too late. The Doctor asks him why the Daleks needed outside help from Cybermen and mercenaries, but the Emperor says they’re no more than scapegoats - they’ll be blamed for what’s happened by the Galactic Council and when they‘re no longer needed they’ll be exterminated.
The Doctor’s companions are brought in by the Cybermen and Karl’s mercenaries and although the envoy is starting to recover and can now walk unaided, he still seems dazed and isn’t talking yet. The Emperor Dalek says he’s brought them all together so they can witness the destruction of the Doctor’s TARDIS. A suspension beam is activated and the TARDIS appears above them. The Daleks open fire and the TARDIS explodes before their eyes! Oddly, the Doctor doesn’t seem remotely concerned and says the ship was getting on a bit anyway. In return, the Doctor offers a trick of his own. He produces a black box and reveals that he recorded their earlier conversation. He plays it back and the entire group listen as the Emperor Dalek explains how he’s betrayed the Cybermen and mercenaries and plans to destroy them all. The Cyber-leader orders his troops to attack the Daleks and Karl also rallies his mercenaries. Within moments the entire chamber is filled with the noise and heat of a huge battle. The Doctor gathers together Jason, Crystal, Zog and the envoy and, with the aid of Karl who provides them with covering fire, they manage to escape from the room.
The Doctor leads his friends towards the TARDIS and explains that he knew all along that it hadn’t been destroyed. It was just a Dalek illusion to make them think they’d lost everything, but he realised it was a trick because his ship is indestructible. He hurries everyone inside and tells them they have a lot to do and very little time in which to do it. Moments later, the TARDIS dematerialises…
Back on Earth, Crystal is amazed to discover they’re going for tea with Mrs T at Downing Street, but Jason is very casual about it and says he’s been here before. The Prime Minister thanks the Doctor and says they owe him and his friends a great debt. She says the envoy is understandably tired, but he’s ready and able to go ahead with the peace conference which is due to begin very shortly. After she’s left, Crystal says she needs to go back to her own Number Ten too as rehearsals are due to start soon. She prepares to say goodbye to her new friends, but notices the Doctor seems distracted. He promises to pop by later and see her performance, then once they’re alone, he tells Jason he thinks they won too easily. He knows they faced great dangers, but there were so many times when the Daleks could have killed him but they didn’t. Why did the Emperor want him alive and why was he so confident the peace conference would be blown up? It’d be impossible for anyone to plant a bomb there, but the way the Emperor Dalek spoke to him made it sound as if he himself was part of the Daleks’ plans. Jason says that doesn’t make sense because all the Doctor did was bring the envoy back to 10 Downing Street in time for the conference. Suddenly the Doctor realises what it all means - this must be exactly what the Daleks wanted all along. He grabs a phone and says it’s urgent the American envoy comes here to meet the Prime Minister immediately.
While they’re waiting, the Doctor rummages around for the voice changing device he used back on Skaro. Before long the envoy arrives to meet Mrs T and the Doctor says he’d like a word with him first. He speaks to the envoy with a Dalek voice and asks him what his mission is. The envoyn produces a silver egg-like device which the Doctor identifies as a Dalekenium bomb, powerful enough to take out most of central London. On further questioning, the envoy reveals that forged evidence has been planted at the conference incriminating each world power. They’ll all blame each other and war will begin, then the Daleks will invade after the fighting is over. The Doctor tells him his mission is cancelled and orders him to hand the bomb over, but the envoy activates the timer and the Doctor discovers they only have about 20 seconds before it goes off. The only thing that could possibly defuse it in time is tannic acid in a high temperature solution. Fortunately he has some right here - in a good, strong pot of tea.
Margaret returns and demands to know what’s wrong with the envoy as he seems to be in some kind of trance. When the Doctor explains that he’s undergone a temporary catatonic withdrawal as a result of his terrible experiences, Mrs T is horrified as the conference is about to begin and the envoy’s presence is vital. The Doctor agrees to help and uses the crystal pendant to counteract the Daleks’ brainwashing. He starts to hypnotise the envoy…
At the Number Ten nightclub in Clarendon Square, Crystal finishes another perfect rendition of the love duet “Sky High”. The audience bursts into applause and the Doctor and Jason congratulate her on a marvellous performance. Jason tells her he wouldn’t have missed it for all the world. Crystal has read in the news that the peace conference is going well and the American envoy made the speech of his life. The Doctor admits that after removing his conditioning, he may have added a little extra confidence too. Crystal asks if she can speak to the Doctor alone and tells him she’s upset that Jason hasn’t revealed his true feelings to her. The Doctor points out that they’re from different countries, cultures and times, but he says they must both work out for themselves whether they want to take the risk. He adds that he’s had many companions travelling with him over the years - Susan, Jamie, Zoe, Leela, Peri and Evelyn - but they always leave him eventually to look for their own happiness and most of them seem to find it. Crystal asks him if he ever misses them and he says he does…every single day!
As Jason returns, the Doctor goes back to check on the TARDIS. The young Frenchman asks Crystal to come with them, but she says that although she really likes him, her career is going really well at the moment and she can’t just give it up. Jason understands and says it wouldn’t be reasonable for him to ask. They prepare to say goodbye, but as they kiss they hear the club MC announce Crystal’s next song. Jason leaves, but then Crystal suddenly calls after him and they both embrace. The Doctor and Zog peer out to see what’s happening and see the young couple in each other’s arms. The Doctor asks whether Jason is staying here or whether Crystal will be travelling with them…and Crystal decides that she wants to come with them. They enter the TARDIS and the Doctor announces that he hasn’t got the slightest idea where or when they will be going next…