The Doctor speeds through the English countryside in his restored yellow roadster, Bessie. He sings an aria from Rigoletto as he drives into a vast industrial complex. He waves happily at the guards and drives into a restricted era.
He passes a big cheerful man named Slocum, bicycling through the complex and whistling. Slocum stops to chat with a technician about the drilling project before finding his way to a large sophisticated control room that is bustling with technicians. He find Sir Keith Gold - a dignified middle-aged man - and asks him about the #2 output pipe. Keith takes him into another room that is filled with noise and heat emanating from a central pillar of machinery. Keith shows him a leaking pipe and asks him to repair it.
A bearded gruff man - Professor Stahlman - appears with Dr. Petra Williams, a pretty blond woman who is the Assistant Director of the project. He asks her why drilling has been slowed and Keith tells him about the damaged pipe. Stahlman is annoyed that drilling has been slowed without asking for his authorization. He angrily tells Sir Keith that, as executive director, he should stay focused on keeping the canteen stocked and leave minor drilling problem to him. Keith reminds him there is no such thing as a minor drill problem but Stahlman dismisses him.
Slocum is tightening the pipe down when a green liquid bubbles up through the grating. He touches it and it burns his hand. He then hears a ringing in his head and becomes disoriented as his hand begins to turn green.
Keith asks Petra why Stahlman is so defensive. After she explains that the project is all he has. Keith tells her he's bringing in another consultant - Greg Sutton, an oil driller. He wants someone on this project with a good practical knowledge of drilling - and its dangers.
Slocum emerges from the drill area in a daze. Stahlman, thinking the pipe repaired, orders the drilling rate increased to make up for lost time.
As Slocum stumbles out into the complex, a scientist sees him. He approaches the engineer and tries to help him. But Slocum gives an inhuman roar and strikes him down with a wrench.
Some time later, the Brigadier arrives at the complex and enters his office. Benton, busily arranging it, tells him they have made no progress in finding Slocum. The Brigadier tells him to keep the murder quiet.
The Doctor arrives. After joking with the Brigadier about his class picture, he is informed of the recent events. The Brigadier shows him the wrench used in the murder and Benton tells him Slocum was one of the most popular men in the complex. The Doctor finds the wrench still warm and the Brigadier tells him it was white hot when found.
The Brigadier asks why the Doctor has come and the Doctor replies that he is interested in the first penetration of the Earth's crust. The Brigadier is skeptical of this explanation as the Doctor leaves to continue his experiments.
Greg Sutton, a robust man in his 30's, is brought to Sir Keith. Sir Keith explains that he asked for the best oil rig man they could find. He shows Sutton the drillhead, which is like nothing Greg has ever seen. He explains that they are using a nuclear-powered robotic drill which is now twenty miles deep. He jokes that the engineers have dubbed the project "The Inferno". They are drilling to find the pockets of Stahlman's gas that should lie just underneath the Earth's crust and provide Britain with an immense amount of energy.
The countdown reaches 60 hours as Sutton is introduced to Petra. The oil man is fascinated by the pretty woman but she is dismissive of him. He is then introduced to Stahlman, who rants about Gold constantly bringing in experts to drag the operation to a halt. As the Doctor enters, Stahlman cries out "there's another one!" and the Doctor taunts the Director about his liver playing him up.
Keith introduces Sutton to the Doctor. The Doctor is concerned about the warnings coming from one of the computers. He's not wild about computers but thinks it's stupid to ignore them. He flips a switch to siphon off power for his own project.
Stahlman tells Petra all the experts are a waste of time -- just in time for the Doctor to spot a technician making an error that could cost thousands. As the Doctor happily heads back to his hut, Stahlman fumes that he's "losing patience with that man!".
The Doctor drives out to his hut and uses his sonic screwdriver to open the door. Inside, Liz Shaw, his assistant, is working on the TARDIS console. The Doctor tells her about the murder but maintains that they came there to tap the nuclear generator to get the console working. They activate the console and begin feeding power into it.
Slocum sneaks around - his skin completely green, black hair appearing over his body. He breaks into the power reactor, knocks out the technician, grabs a lever and sends the reactor to full power.
The TARDIS console start shaking. Liz tries to cut the power but is unable to before the Doctor and console vanish. The Doctor finds himself in a black void, clinging to the TARDIS console, with mysterious forces pulling at him.
Liz finally manages to cut the power and the console reappears with a reverberating crash. The dazed Doctor tells her he went nowhere -- he was in a limbo pressing against a barrier he couldn't break through. He wants to make another trial run -- because of what happened.
Klaxons rings through the complex and the Doctor and Liz rush to the drill head. Heat shutters close over the drill and smoke pours through the complex. Stahlman demands the shield be raised while Petra tries to contact the reactor. Unable to get them, she rushes into the drill area over Sutton's objections.
The Doctor and Liz arrive. The Brigadier informs him that a soldier has been killed near the reactor. The Doctor tries to speak to Stahlman. When the Director won't listen, the Doctor berates him and heads off with Liz.
Petra reports that the coolant controls are jammed with the heat. Greg tries to stop her going back in but she's confident Stahlman can deal with the crisis. The engineers continue to struggle with the coolant valves as Sutton races in to help.
The Brigadier and Doctor arrive at the reactor and find the dead technician. As they examine him, Slocum leaps out from the shadows. He growls as he moves toward them...
The Doctor motions Sergeant Benton to stay back from Slocum as the mutating man growls at them.
Greg gets the coolant flowing again, saving the drill. Stahlman tells Petra to call the reactor and find out what happened.
The phone in the reactor room starts ringing. While Slocum is distracted, Private Wyatt sneaks around the equipment. He pops out and shoots Slocum twice. But Slocum throws him to the ground before collapsing against the wall. The Doctor uses the Brigadier's pistol to push the red-hot reactor lever back, slowing the power output. Slocum roars in protest and collapses, leaving a scorch mark against the wall. The Doctor answers the phone and testily inform Stahlman that they've dealt with the problem.
Greg jokes with the engineers about striking an Order of the Turkish Bath for their heroism. But Stahlman orders them back to work. Sutton insists that they should slow the pace, make allowances for potential problems. But Stahlman won't listen. Greg then tries talking to Petra, who is starting to warm to him. He asks her to talk to Stahlman -- maybe he will listen to his Assistant Director.
Bromley, the reactor technician, and Wyatt seem very confused and disoriented after Slocum's assault. The Doctor warns the Brigadier not to touch them. They go out to talk on a gantry and the Doctor admits he's not sure what's going on -- why Slocum has transformed. The Brigadier worries about keeping it quiet and comments that he'd never heard a sound like Slocum's screeching. The Doctor replies that he has - during the eruption of Krakatoa.
Benton comes up and tells them the two men have disappeared. As he and the Brigadier rush off to investigate, the Doctor hears screeching and spots Wyatt on a gantry. He runs off in pursuit, climbing over fuel tanks. Wyatt is already changing, his skin turning dark green. He attacks the Doctor, using his rifle as a club, and falls off the gantry. When soldiers go to investigate, the Doctor warns them not to touch Wyatt. As he goes down Bromley appears in the background, also transformed.
Stahlman tells Petra he has found a way to advance penetration zero by five hours. But she bring him into the control room to see something brought in by Sir Keith.
Keith opens a small box and takes out a cylinder of green slime. He explains that it has been coming up in the waste pipe in greater and greater quantities. They can't analyze it because it is too hot. The Doctor opines that it's not going to cool down for them.
The Brigadier demands to speak with Stahlman and Gold. As they go off, the Doctor gazes at the green slime and wonders if it screeches. But Liz interrupts to tell him that he needs to look at the main computer -- it's telling her something downright frightening.
Stahlman insists to the Brigadier that the death are a personnel problem, not a scientific one. He dismisses the Doctor's concerns even though the Doctor has already given critical help to the project.
The Doctor bursts in and asks if anyone is going to pay attention to the warning of the computer. Stahlman dismisses the computer as unreliable, prompting the Doctor to call him a nitwit.
Petra rushes in and tells them the jar of slime is cracking. Over the Doctor's objections, Stahlman grabs the jar with his bare hand and puts it backs into the box. He refuses to discuss the situation any longer - he has been working on the program from 11 years and knows it better than any computer.
The Doctor, however, tells him the computer's message is perfectly clear if Stahlman cares to check. Stahlman continues to ignore the computer and the Doctor finally gives up and decides to go back to his hut. But Stahlman decides they need all the power for the drill and refuses to send any more power to the hut. He then tells Petra to accelerate the drilling.
But his hand is already beginning to turn green.
The Doctor sends Liz back to continue work on the console and then quietly turns the power back on to his hut.
Stahlman opens the computer console and removes a transistor. He takes it into the Brigadier's office and prepares to smash it. But he is interrupted by the Doctor who uses his Venusian akido to stop him. The Brigadier interrupts their confrontation and Stahlman demands that the Doctor be expelled before leaving.
The Doctor chases him out into the control room and demands that he empty his pockets. Stahlman, however, no longer has the microcircuit. The Doctor leaves in disgust as the computer begins to fail. After he leaves, Stahlman goes to the circuit, which is lying in a corner, and crushes it beneath his heel.
The Doctor returns to his hut. He insists to Liz that the TARDIS console is working fine -- the problem was the power surge. He then asks the young woman to run some epsilon coordinates for him back in the computer room. He insist he's tired but when she leaves, he rapidly sets to work on the console.
When Liz reaches the control center, she finds the computer dead. The Brigadier recalls that the Doctor was there when it started failing. Liz realizes what is happing when she sees that the power is back on. She and the Brigadier races back to the hut.
The console begins shaking as power builds.
Stahlman starts accelerating the drilling when he realizes that power is being drawn off. He goes to control room and angrily switches off the power to the Doctor's hut.
The Brigadier and Liz returns just in time to see the Doctor, the TARDIS console and Bessie vanish into thin air...
Liz and the Brigadier returns to the control room and ask Stahlman to restore the power. He refuses. Keith is now upset that Stahlman is accelerating the drilling without authorization. But Stahlman points out that no one will object since he can provide so much cheap energy to the nation.
Sir Keith decides to head to London to officially complain. But he is pessimistic. The Ministry has been dazzled by Stahlman's promises.
Stahlman's hand is turning greener. He covers it up with a pair of white gloves.
Liz asks the Brigadier why he doesn't appear worried. But Lethbridge-Stewart tells her that between Stahlman, the Doctor and the murders, he's plenty worried.
In another place . . . another world . . . the Doctor comes to. He checks the TARDIS console but there is no power. He notices that his lab is different. There is a picture of a grim-looking man over the motto "Unity Is Strength". His sonic screwdriver fails to open the door. There is a crossed arrow symbol on the door.
He gets in Bessie and drives out into the complex. Suddenly, a soldier starts shooting at him. The Doctor races off in Bessie as a very brutal Sergeant Benton arrives with a group of soldiers. Benton is wearing a fascistic uniform with a crossed arrow symbol on his beret.
The soldiers maintain their pursuit of the Doctor. He finally pulls over and hides in a dustbin, then escapes to a gantry. As he does, he hears a screech and turns to see Bromley. The Doctor uses a fire extinguisher to neutralize the maddened technician but he is spotted by the soldiers. Wyatt appears and attacks. As the Doctor evades the maddened soldier, Benton orders his men to shoot at the first thing they see. But they shoot the deranged Wyatt, who plunges from the tall cooling tower to his death.
A dark-haired woman in tall black boots walks quickly through the complex. The Doctor recognizes her as Liz and calls out to her. But she pulls a gun and uses a whistle to summon the soldiers.
The Doctor is dragged to the Brigadier's office -- now stark and bare. When The Brigadier turns around, he has a massive scar on the left side of his face and patch over his eye. He doesn't recognize the Doctor and tersely interrogates him, with Benton uses his rifle butt to assist.
He tells the Doctor he is the "Brigade Leader" while Liz is the "Section Leader". They demand his name and the Doctor, realizing what has happened, gives the moniker of Dr. John Smith. He tells them he has come from a parallel universe. Liz thinks he must be deranged but the Brigade-Leader thinks it's an act.
They are concerned that he knows their names. And when the Doctor asks about Stahlman, Sir Keith and the shaft, they become convinced he's a spy. The Doctor asks to see Stahlman or Gold and the Brigade-Leader agrees -- the Doctor won't be leaving alive anyway. Benton takes him into the control room and the Doctor notices that they are a mere three hours away from penetration zero.
Stahlman appears. He is dressed in white, his face clean-shaven, dark glasses on his eyes. He is amused that the Doctor wants to see Sir Keith and informs the Time Lord that Gold was killed in a car accident 24 hours earlier. Stahlman simply laughs off the Doctor's story of coming from a parallel world.
The Doctor asks about the sabotaged computer, pointing out that a microcircuit is missing. Stahlman promptly accuses him of sabotaging it. Benton drags the Doctor back into the Brigade-Leader's office.
Sutton, now wearing a suit and tie, tells Petra they have no pressure in the coolant pipes. The Assistant Director, dressed in white with her hair severely bound, coldly ignores him. He worries about what will happen in a an emergency. But when he pushes her, she rebukes him and threatens to report him.
She then tells Stahlman they are exceeding the safety margins. He refuses to make any changes and retreats to a corridor as a buzzing sound fills his head. His hand is completely green with coarse hair growing over it.
The Doctor waits in the office while the Brigade-Leader fills out some paperwork. He tells the Doctor that he will be shot eventually. He explains that he is an officer of the Republic -- the royal family having been executed -- and he is there to supervise a scientific slave labor camp.
The Doctor replies that they are all in grave danger, which amuses the Brigade-Leader. The Doctor reminds him that, before the computer failed, it was warning of danger. He reminds the Brigade-Leader of Harry Slocum, which convinces the Brigade-Leader that he is indeed a spy. The Doctor again insists he has come from another world but the Brigade-Leader tells him they are checking his identify. When the Doctor tells him he doesn't exist in their world, the Brigade-Leader retorts, "Then you won't feel the bullets when we shoot you!"
The Brigade-Leader is called away and Liz informs him they have found nothing on the Doctor. Lethbridge-Stewart stuffily reports this to the Doctor, who taunts him about not being able to shoot him without filling out the proper forms. Liz tells him he has very little time left and the Doctor replies that they all have very little time left.
Petra reports that #2 output pipe is now leaking debris. Greg wants to have it looked into since there is no such thing as a minor problem at the drillhead. But Stahlman tells him to mind his own business. As he leaves, Greg grumbles, "No, Director. Sorry, Director. Three bags full, Director."
Suddenly, alarms ring through the complex. Liz and the Brigade-Leader rush into the control room to investigate. The Doctor calls Benton over and overpowers him.
The Brigade-Leader calls up the security guards to keep the technicians in the control room.
The Doctor sneaks into the control room, finds a tool box and begins to work on the computer.
The Brigade-Leader and his men pull guns as the technicians try to flee. He tells them that "if this place goes up, we all go up with it!".
Stahlman spots the Doctor working on the computer and summons Benton. The Doctor looks up to find a rifle pointed at his head. He explains that he's trying to fix the computer but Benton tells him they have a firing squad ready for him. The Doctor insists they will all die if the doesn't fix the computer. But Benton simply levels his rifle and asks the Doctor if he's ready to go quietly or wants to be shot here and now...
Liz stops Benton -- but only because she wants to follow the correct procedure. Over their protests, the Doctor repairs the computer and it starts spitting out data. The Doctor pores over the readings.
Stahlman demands to know what the Doctor is doing and Liz points out that the computer is working now. Stahlman insists they are doing fine with his calculations but Greg points out his calculations can't deal with the current crisis.
The Doctor and Sutton hatch a plan to reverse everything -- take the waste in through the input pipe while pumping coolant down the output pipe. Stahlman resists but is forced to concede. The Doctor is then dragged off.
Liz questions him again but the Doctor sticks to his story. She asks about her other self and the Doctor tells her she's a scientist in his world. She points out that she's really a security office but the Doctor gets her to admit she studied A-level science. The Doctor encourages her to use her skilled mind to overcome the narrow bigoted world she lives in.
The pipe reversal works. Sutton asks Petra about the Doctor and she replies that he's a saboteur. When Sutton tells her he will have to slow drilling to fix the output pipe, she says he will protest, but Sutton insists there is no alternative. Petra points out that if he wasn't so insolent, he'd have a brighter future. His technical skills have kept him alive but he might be disposed of once the project is finished. He asks her if she'd care and she replies that she would regret the waste.
Liz tells the Doctor that the emergency has passed. She continues that if he tells her the truth, she can help him. But the Doctor only replies that the emergency is not over -- they are still rushing into terrible danger.
Stahlman tells Sutton they will accelerate the drilling again. Sutton points out that the drill is only still working because of the Doctor. The only reply is another warning that bad things will happen to him if he continues to act up.
But Stahlman is beginning to give in to the alien influence of the slime.
The Brigadier and Liz interrogate the Doctor but he sticks to his story. He begins to loses consciousness and they scale back their treatment. But the sound of the accelerating drill bring him back and they resume.
They are interrupted by Stahlman. The Doctor notices his white gloves and asks him to take them off. Stahlman does and shows him a bandaged hand. The Doctor reminds him of the jar and speculates that Stahlman has been infected by the green slime. Benton hauls the Doctor to the cells. Stahlman insists that the Doctor should be liquidated.
Sutton tells Petra that they should have checked the drill while it was powered down. When she insists that Stahlman knows what he's doing, Greg tells her that Stahlman is a nut. For once, Petra doesn't report him.
The Doctor is taken to a prison. He sees a prisoner sleeping in the next cell. Liz is brought in and tells him the interrogation is going to continue. The Doctor ignore her and lies down but is forced to stand when Benton again threatens to shoot him.
Liz resumes her questioning but he insists that he has told her the truth. Benton offers to rough the Doctor up but Liz sends the soldiers away. She tries talking nicely to the Doctor but he sees through the ploy. She tells him she thinks he's from a crackpot free speech group but the Doctor insists this is not the case.
After she leaves, the Doctor tries to talk to his neighbor. He gets no response . . . except a green claw emerging from beneath the sheet.
Back in the real world, the Brigadier tells Liz they've found no sign of the Doctor. He assures her that the Doctor can look after himself.
Sir Keith tells Stahlman he's going to London to express his concerns with the way things are going. He wants more precautions and a way to shut down drilling in an emergency. Stahlman is at first conciliatory but quickly becomes enraged and points out that he has fought hard for the project and won't brook any more delays.
Liz and the Brigadier ask if the Minister will listen and Sir Keith is uncertain. He will come back for penetration even though he has a foreboding about it. He asks where the Doctor has gone and remarks that, wherever he is, he's better off out of it.
In the parallel world, the Doctor wakes to hear screeching in the next cell. He calls out for the sergeant. The soldier goes into the cell but Bromley knocks him out. Bromley then rips apart the cell bars. The Doctor uses a mattress to fend him off and escapes out the open door. He climbs into the back of a nearby range rover.
Petra tells Greg they are only 35 minutes away from penetration zero.
The Doctor finds heat-protective suits in the back of the rover and begins to put it on.
Benton finds the Doctor has escaped and begins a search.
There are now three minutes left. The Doctor joins a bunch of hooded figures and goes back into the control room. The countdown reaches two minutes as the Doctor steps out of line and goes to the computer. The Brigade-Leader notices and tells him to come down.
The Doctor steps down and rips off his mask. He pleads with them to stop drilling. Stahlman tells the Brigade-Leader to shoot him but Sutton protests.
A loud buzzing noise emerges from the drillhead. "Listen to that!" cries the Doctor, "It's the sound of this planet screaming out its rage."
Stahlman again orders the Brigade-Leader to shoot the Doctor but Sutton jumps him. Soldiers close in as the Doctor tries to escape. Stahlman picks up the gun and points it at the Doctor as the countdown reaches zero...
A massive explosion rocks the center at penetration zero. The soldiers want to shoot Sutton but he stays to cap the bore as the technicians flee.
Sutton tells the Doctor he can cap the bore if he gets coolant flowing. Stahlman is set to go in but Sutton tells him he needs a fire suit. The Doctor remarks that Stahlman doesn't feel the heat as they do.
Another explosion rips through the building. Green slime oozes from the pipes.
The Doctor and Sutton don their masks and head into the bore. Technicians are passed out all over the drillhead. Sutton tries the coolant valve but Stahlman sneaks up and slams a pipe into his back. Stahlman drags Sutton over to the drill and takes off his mask. The Doctor attacks him and they roll around on the floor as Greg recovers. He strikes Stahlman down and the two men retreat from the drill head.
Liz asks why Stahlman is still in the drill head and the Doctor replies that he likes it in there.
Sutton is determined to go back in but a steel blast door closes, sealing it off. Stahlman then locks the controls. Stahlman begins dragging the technicians to the drill and forcing their faces into the green slime.
The Doctor reads the data strip from the computer. He asks Sutton what the blast doors are made from and Sutton tells him they were built to stand up to an atomic blast. The Doctor replies that an atomic blast would seem like a summer breeze compared to the forces they have unleashed.
The Brigade-Leader reports that the technicians have all fled. Petra then tells him the computer has broken down. She asks if he has heard any news from London and he tells her seismic disturbances are being measured all over the country. They are evacuating the area and have given the Brigade-Leader executive control. Greg opines that they have been abandoned.
Sutton asks the Doctor if there is anything to be done. The Doctor says it is too late -- nothing can seal the bore. The heat and pressure will eventually dissolve the surface of the planet, leaving it uninhabitable in a matter of weeks or even days.
Bromley arrives and tries to get to the drillhead. The Brigadier shoots him and he staggers on. The Doctor uses a fire extinguisher to finish him off.
Sutton wants to leave since they are all doomed. Liz reminds him they were ordered to stay and the Brigade-Leader points his gun at Sutton and tells him to do his duty. Sutton taunts him about what his precious dictator is doing now and the Brigade-Leader rages that he will not listen to treason. The Doctor tells them to save their energy.
Benton reports his men are ready and the Brigade-Leader orders them to seal the building. Greg laments that "the world is going up in flames and they're still playing toy soldiers!" Benton leaves and rousts his men out.
Greg tells Petra they should just leave but she continues to work on the computer. Greg tries to persuade her that they are doomed -- no one is being allowed in; if they thought there was a chance of saving the project, they'd be sending in experts. Petra begins to realize he's right -- they're just going to die there. She finally breaks down and goes into Greg's arms. He assure her he will get them out.
[Note: In the North American broadcast, there is a scene of The Doctor, Brigade-Leader and Liz listening to a radio broadcast reporting the events].
Liz tells the Brigade-Leader there's nothing to be done. But the Doctor tells them they can save one world -- his. The Brigade-Leader is skeptical but the Doctor explains that if they can get power to his TARDIS, he could go back. The other project isn't as advanced and he could stop them. The Brigade-Leader unexpectedly agrees to have a look at the console. As they leave, he tells Petra to keep working. Sutton wonders where they are going and assure Petra they will get out.
The Brigade-Leader and Liz are unimpressed by the TARDIS. The Doctor flips a switch and the column moves on a bit of residual power. The Brigade-Leader is still skeptical and the Doctor makes a short jump in time using the last of his power. This finally convinces the Brigade-Leader and Liz.
The Brigade-Leader asks if the Doctor can take others with him but the Doctor explains that it is too dangerous. They would create a dimensional paradox and shatter the spacetime continuum.
Stahlman calls out to Petra over the intercom. She calls Greg who insists that no one could be alive in there. The Doctor and the others return as Stahlman calls out again, asking Petra to raise the heat shield -- the interior controls are jammed with the heat.
The Doctor tells her not to but the Brigade-Leader insists that if Stahlman has found a solution, they need his help. He forces the Doctor to back off at gunpoint.
Petra raises the shield. A figure with green claws steps out. Petra goes to him but the Doctor holds her back. Stahlman pulls off his mask to reveal a full primord -- his face green and covered with thick fur. He waves and other primords emerge from the drill head.
The primords hesitate, acclimating to the temperature. Greg tries to run but the primords block the exits. Benton enters and primords grab him. Stahlman runs his hands over Benton's face and the soldier falls to the ground, screaming.
In the confusion, the Doctor rips the wires out of the door control and its slams shut, cutting off the primords. The survivors race into the Brigade-Leader's office, leaving Benton behind.
Benton rolls on the ground screaming in pain. He quickly changes into a primord.
Sutton is angry that they've left Benton behind but the Doctor assures him there's nothing to be done. Worse than being killed, Benton will now be one of them. He explains that the primords draw strength from the heat.
The Brigade Leader laments that they can't get to the Doctor's spacecraft now. Greg asks to be told what's going on.
Back in the real world, Sir Keith is in a Ministry car. His driver is taking a strange route and the phone doesn't work. Gold is impatient -- the Ministry has agreed to suspend and review the project. When he realizes they are in the middle of nowhere, the driver reluctantly admits that Stahlman ordered him to take Sir Keith into the country and stage a breakdown. He agrees to hurry back to the complex. But as he apologizes, he swerves into an oncoming car.
In the parallel world, the primords begins to recover in the heat and start pawing at the Brigade-Leader's office door.
The Brigade-Leader concludes that they must all sacrifice their lives so that the Doctor can escape. Liz points out that they are dead anyway. Greg says that it's a weird story but he's prepared to believe it. The Brigade-Leader scoffs that they are trapped anyway. The Doctor says that he has a plan for getting out. But before he can elaborate, a green claw smashes through the door's window...
|The Doctor grabs a fire extinguisher off the wall and uses it to fend off the primord. He tells the others the primords won't return until the temperature rises. Their first step is to connect power to his TARDIS. He checks the ventilators and confirms that there is still power.
Petra tells him it will be complicated. She will have to reset the power switch, go to the reactor and turn up the power. The Doctor suggests they use the fire extinguishers to get past the primords but Petra objects that it may take too long.
Greg then remembers that he rigged up an emergency coolant hose. If he can get it free, they will have a monster fire extinguisher.
The primords return. The Doctor opens the door and Greg uses the extinguisher to chase the primords back. The Brigade-Leader holds the primords at bay while Greg works to free the coolant hose. Stahlman tries to sneak up from behind but the Brigade-Leader spots him and hit him blasts from the extinguisher. He then chases the others back until the Doctor tells him not to waste the coolant. Stahlman is paralyzed with the cold, but not dead.
Just as the extinguisher runs out, Greg gets the coolant pipe free and chases the primords back. The Brigade-Leader, Liz and Petra race out as Greg holds them off. They get outside and notice it has become incredibly hot. The Brigade-Leader wants to go but Petra and Liz insist on waiting for the others.
The Doctor is making slow progress with the switch. Greg asks him how he knows the other world will stop the drilling. The Doctor hopes that Sir Keith is still alive and will listen to him.
In the real world, the Brigadier is trying to get word of Sir Keith. Benton reports that Stahlman won't come to see him. The Brigadier tells the sergeant to carry him in if he has to.
Liz tries feeding power to the hut, hoping it will bring the Doctor back. Someone tries the door and she opens it. It's Sutton, looking for the Doctor. He was passing by and wanted to see the machine the Doctor was working on. He wonders about the disappearance since no one saw the Doctor leave. Liz tells him she hopes he'll return soon and Greg speculates the Doctor blew himself to pieces and they're trying to cover it up. Liz is about to tell him the truth but hesitates. He tells her Sir Keith has vanished as well.
Stahlman is furious at being dragged from his work but the Brigadier insists on having words with him. He tells him that Sir Keith has disappeared and Stahlman speculates Sir Keith's complaints were dismissed and he's gone off in a fit of pique. The Brigadier asks that he delay penetration until Sir Keith returns but Stahlman refuses.
In the parallel world, the Doctor has finally reconnected the switch. Greg drives the primords back and then the two men run for it. Stahlman begins to revive.
The Doctor and Sutton join the others and head to the nuclear reactor. Petra will have to rewire the switch before she can boost the power.
As the Doctor and Sutton go to get some heavy cable and wire up the hut, massive earthquakes begin to shake the complex. It is now hot enough that Stahlman and the primords are able to leave the control center.
The Brigadier, frightened by the earthquakes, pressure Petra to hurry. She tells him to stop bullying her. The Brigadier tells Liz he intends to force the Doctor to take them along.
The Doctor and Greg reach the hut. Greg is unimpressed by the machine. The Doctor explains that the TARDIS slipped them sideways in time. Greg tells him the cable will blow in seconds if they try to put the reactor's power through it but the Doctor assures him that a few seconds are all he will need.
Petra continues to work as more earthquakes hit. The Brigade-Leader is scared and Liz defiantly tell him they're still there. The Brigade-Leader wants to leave, his facade breaking. Liz asks where he will go and he insists he can force the Doctor to take them along. If he can't, he'll get Petra to figure out the machine. He finally insists that if the Doctor leaves them to die, he will die.
Sutton tells the Doctor to make damn sure he stops the drilling. Greg hopes for luck but the Doctor reminds him they are relying on skill.
Petra tries the switch and it doesn't work. She will have to start all over again.
More explosions rip through the complex and Greg worries that they will reach the nuclear reactor.
Petra is still working when Stahlman attacks. The Brigadier shoots Stahlman and makes them run. Other primords give chase. Earthquakes knock them all flat. They reach the Doctor's hut and reluctantly inform him that they weren't able to repair it. The Doctor laments that they gave it their best shot but the Brigadier is bitter.
Greg mocks the Brigadier, who pulls his pistol. When Greg comments that he's only be doing him a favor, the Brigadier pulls the trigger. But the weapon is empty. They fight with each other until the Doctor asks them if they want to die like animals. They notice that Petra is gone and Liz tells them Petra's gone back to the reactor. Greg chases after her.
Petra is working on the switch as Stahlman begins to revive. Greg asks her what she thinks she's doing and she reminds him that nothing else matters except helping the Doctor. Stahlman gets up and takes a swing at Petra. Greg uses a fire extinguisher to finish Stahlman off. Petra completes the circuit and the power comes back on. They race out to the Doctor's hut.
The console begins to work. Petra and Greg urge the Doctor to take off before the power fails. The Brigade-Leader says it will last long enough and pulls his reloaded gun. The Doctor says he wishes he could take them back but he literally can't. He tells the Brigadier he will just have to shoot him. But a shot rings out and the Brigade-Leader falls, gunned down by Liz, who urges the Doctor to take off.
As the Doctor activates the control, a tremendous detonation destroys the control center. Massive eruptions follow and lava rains down. The Doctor tries to take off but the power is too erratic.
Petra cries out to Greg and goes into his arms as they see a massive wall of lava advancing on them...
|The Doctor finally takes off and reappears unconscious in his lab. Liz returns and finds him. She sends Benton to get help.
The countdown has reached three hours and 22 minutes. Stahlman wants to accelerate drilling again. They will be over the safety margins but Stahlman dismisses Petra's concerns. She tells Greg. He wants to reason with Stahlman but she tells him he won't listen. Greg thinks Stahlman is losing his grip and is worried that a mistake at this stage could be a big one. Petra agrees to talk to him.
Benton tells the Brigadier that the Doctor has returned. He is overheard by Sutton.
As Petra talks to Stahlman, the director begins to hear a ringing in his head. He recovers and insists the can't slow down. Greg tries next, telling Stahlman he's been working on the program for years. There's no need to rush. Stahlman insists that penetration zero must be achieved at the earliest moment as a ringing fills his head again.
Liz checks the Doctor's pulse and finds it steady. She's not sure when he'll come out of his coma but tells the Brigadier she will take care of him for the time being.
Greg tries Stahlman again, warning him of a broken flange on #2 output pipe. He can repair it if drilling is slowed. Stahlman refuses and warns Sutton that he should follow the Doctor and Keith's example and disappear. Greg finally loses it and tells him that, as far as he's concerned, they can blow themselves to kingdom come. But Petra begs him to stay. He responds by asking her to come with him -- he's convinced the project is going to end in disaster. But Petra tells him she would like him there if anything goes wrong -- she's gotten used to his being around. But before anything can happen, #2 output pipe blows and alarms ring out.
The Doctor responds to the alarms and mumbles about #2 output pipe. When the Brigadier confirms this, the Doctor advises them to reverse all their systems before passing out again. Liz runs off to central control.
Stahlman refuses to stop the drill, hoping the riggers can control the damage. Liz arrives and relays the Doctor's suggestion. Greg remembers a similar situation in Arabia in which such an idea worked. Petra wants to get Stahlman's permission but Liz urges her to act on her own. Petra does and the drill is saved. But Stahlman is bitter that Petra has turned on him.
The Doctor wakes up to Liz's voice and is happy to see them. He tell Liz that he went to another world -- terrible things are happening there. He asks the Brigadier if Bromley has been found and how Stahlman is progressing.
There is a knock on the door and Liz opens it to reveal Sir Keith, his arm in a sling. The Doctor is delighted - this means that there is free will and he can still stop the drilling.
The Brigadier calls the medical section, but the Doctor takes the phone from him, insisting that he's neither sick nor a raving idiot. He tells Sir Keith they need to stop Stahlman or there will be a disaster. He knows because he has already seen it.
He bursts into the control room and demands that they stop the drilling. When no one listens, he grabs a spanner and begins smashing controls. The Brigadier has him dragged out. As he goes, the Doctor tells Liz to repair the computer Stahlman sabotaged.
Sir Keith confronts Stahlman, who denies ordering the driver to divert from his route. He insists he will put up with any inquiries . . . after they have penetrated the Earth's crust.
Petra talks to Stahlman in the drill head. He insists it's getting cold and is hearing a ringing in his head. He tells the technicians to leave and forces them out, then closes the heat shield.
The Doctor is being escorted by soldiers. He knocks them out and escapes into the works. Bromley approaches him and the Doctor uses an extinguisher to knock him out.
Stahlman takes the green slime from the drill and rubs it on his face. The others try to raise the shield, but he's locked it down. He transforms into a primord.
Liz repairs the computer and it tells them to stop drilling immediately. Sir Keith says that he can't give the order -- only Stahlman can. The Doctor returns and demands they stop but Sir Keith again refuses.
Suddenly, the heat shield lifts and Stahlman rushes out. The Brigadier shoots him and Greg and the Doctor use the fire extinguishers to finish him.
Petra agrees to stop the drill and they cut the power. But the drill keeps going, having reserve power for five minutes. The Doctor and Sutton race into the drill head. Stahlman has smashed the servo controls but the Doctor works to repair them. He manages to shut it down with 35 seconds left. Liz rushes into the Doctor's arms and Petra into Greg's. The Doctor asks Sir Keith to refill the shaft.
Later, the Doctor happily sings as he works on the TARDIS. Sir Keith and the Brigadier arrive. The project has been officially abandoned. The reactor will be dismantled but it will be around long enough for the Doctor to finish his experiments. Sutton and Petra have left -- together. The Doctor comments that there's nothing like a happy ending.
Keith leaves but the Brigadier tells them he'll be staying around to mop up. The Doctor wants to try the TARDIS again but the Brigadier and Liz object after all the trouble it's caused. They might have cleared up the situation sooner if he'd stayed. The Doctor tells them he tried but the Brigadier chastises him for gallivanting off in a fit of pique.
The Doctor tells the Brigadier there are times when he reminds him of his other self. He decides to leave at once. He turns on the console, which starts to operate. He bids Liz farewell but says he's had enough of "this pompous self-opinionated idiot". He vanishes.
Liz turns on the Brigadier. They start to argue but are interrupted by the Doctor. He is at the door, covered in rubbish. He tells them the TARDIS moved him a few seconds forward in time and a few hundred yards east in space -- to the rubbish tip.
Abashed, he asks the Brigadier if he can help retrieve the TARDIS. The Brigadier reminds him of his name-calling but the Doctor cozies up, telling him not to be so angry and to put on a smile. Liz laughs as she watches the two men walk out.
|Source: Michael H. Siegel.