A bolt of energy draws the TARDIS to a gigantic spaceship, and it materializes inside a Time Lord courtroom. The Doctor, somewhat disoriented, is greeted by a sardonic Valeyard, and finds himself before a jury of his peers, accused of meddling in the affairs of other worlds and of conduct unbecoming a Time Lord. The Valeyard intends to prove to the Inquisitor that the High Council showed too great a leniency the last time it tried the Doctor on charges of this nature. The Doctor insists that he can’t be tried, since he’s President of Gallifrey, but learns that since he neglected his duties he was deposed. The Valeyard prepares to begin by presenting evidence of the Doctor’s interference in the affairs of the planet Ravolox, with evidence drawn directly from the Matrix...

The Doctor and Peri are exploring the forests of Ravolox, which, according to all logic, shouldn’t exist. Time Lord records claim that Ravolox was ravaged by a solar fireball five centuries ago and yet life still exists in abundance. The Doctor’s more interested in the remarkable similarity between Ravolox and Earth; in fact, the planets are alike in every way except for their actual location in the galaxy.

As the Doctor and Peri continue to explore, they’re unaware that they’re being observed by two seedy lowlifes, Glitz and Dibber, who prepare to gun them down on the assumption that they’re poaching on Glitz and Dibber’s territory. But they’re a moment too late; the Doctor and Peri, noticing a native bangle, enter a nearby cave, going out of range. Now Glitz and Dibber have a problem. There’s a fully-functional L3 robot in the complex below their feet, and to render it non-operational they must destroy the maglem mark 7 light converter which provides it with energy, and which the local tribe of primitives worshipes as a totem. But now that they’ve got competition, the two strangers they’ve seen might take the window of opportunity to seize the goods and escape; and if Glitz and Dibber go after them now they’ll run into the L3 robot at its full strength. Glitz decides to risk going for the light converter first; odds are the strangers will be killed before the L3 can be shut down...

The Doctor and Peri, unaware that they’re being observed (and not just by Glitz and Dibber), walk down what appears to be an ancient staircase and find themselves in an underground cavern like a tube station. Peri is appalled when she unearths a sign indicating that that’s exactly what it is; Marble Arch Underground station. They’re on Earth, millions of years in her future, and it’s been destroyed and forgotten. The Doctor is puzzled and determined to investigate the mystery; exploring further, he finds a hermetically sealed airlock and passes through, while Peri, still upset, decides to wait behind. But she’s captured by two primitive warriors.

The Doctor demands to know why he’s being forced to watch events irrelevant to the main point... and suddenly realizes that he doesn’t know where Peri is now. The Valeyard claims that this testimony will become relevant later and suggests that the Doctor may be suffering temporary amnesia due to his removal from the space-time continuum. The evidence continues.

The Doctor finds himself in a sparkling-clean, highly advanced underground complex, but when he picks up a vial of water from a nearby pedestal to examine it further, alarms sound and he is set upon by overalled men bearing clubs. The Immortal, the giant robot which rules the underground complex, detects the presence of a superfluous work-unit at Marb Station and orders the captain of his guard patrol, Merdeen, to cull it.

Glitz and Dibber contact the local primitive tribe and are taken to their leader, Queen Katryca of the Tribe of the Free. Glitz attempts to ingratiate himself with her, claiming that the totem which her tribe worships is a malfunctioning navigational beacon which must be shut down before it causes the fireball which ravaged their planet to return. He learns too late that many other visitors from other worlds have come to Ravolox... each with an entirely different reason why the totem should be destroyed. The tribesmen overpower Glitz and Dibber, take their guns and throw them in prison, where they will be tortured until they tell the truth. Katryca, meanwhile, intends to use the guns to attack the Immortal.

The Doctor recovers from his beating to find himself chained to a post while Balazar, Reader of the Books of Knowledge, organizes a stoning. The Doctor is accused of stealing water, a precious commodity in the underground complex; but he’s more surprised when he learns that the Books of Knowledge of which Balazar is so proud are "The Water Babies", "Moby Dick", and, most mysterious of all, "U.K. Habitats of the Canadian Goose" by H.M. Stationery Office. The stoning begins, and although the Doctor uses his umbrella to deflect some of the missiles he is soon overwhelmed...

The Doctor realizes that the Valeyard’s determination to prosecute him goes far beyond the call of duty. The Inquisitor takes the Valeyard’s suggestion under advisement and the evidence continues...

Merdeen and his guards arrive, interrupting the stoning, and when the Immortal sees the Doctor on his monitors he orders Merdeen to bring the intruder to him. Merdeen also orders Balazar to accompany them; if the Doctor dies on the way the Immortal may wish to question Balazar about him. On the way to the Immortal’s Castle the Doctor recovers, and learns a bit more about the underground complex; all serve the Immortal, and occasionally the brightest work-units are selected to join the Immortal in his castle and are never seen again. The Immortal’s current two servants, Humker and Tandrell, observe the Doctor on their monitor and discuss his physiognomy, and the Immortal orders them to activate an L1 service robot in case it is needed later.

Peri is brought to the Tribe of the Free, where Katryca greets her as a new recruit and offers to find her some excellent husbands. Peri is imprisoned with Glitz and Dibber while she considers the offer, and they question her and are surprised to learn that her companion is a Time Lord. Is that how he knew exactly where to go? In any case, Glitz now has a contingency plan; if he can get the Tribe on his side they can drill a hole into the underground complex and fill it with poisonous gas, wiping out the L3 robot’s labour force and leaving it relatively defenceless. But his plans come to nothing when he and his fellow prisoners are brought before Katryca; she isn’t interested in anything he has to say, and intends to sacrifice him to her gods as appeasement for his attempt to steal the totem.

The Doctor is sent alone into the Immortal’s Castle, while the L1 service robot guards the entryway. Inside, he meets Humker, Tandrell, and the Immortal, who turns out to be an L3 robot named Drathro. Drathro saved the Doctor’s life because it believed him to be from Andromeda; now it recognizes its mistake, but it has another task for him. The black light system which provides it with power is running down, and the Doctor must repair it -- or die.

The Doctor points out that he’s obviously working under duress, but the Valeyard insists that the chain of events they are witnessing was triggered by the Doctor’s decision to visit Ravolox. The evidence continues...

The Doctor eventually determines that the fault lies in the collection antenna on the surface, but Drathro concludes that he is lying in order to escape and orders him to continue with his work. As the Doctor works, he learns more about the complex; Drathro was ordered to maintain an underground survival complex in which the Sleepers could wait for their relief ships to arrive from Andromeda, but the relief ships failed to arrive and the Sleepers are long since dead. Drathro, however, is inflexibly obeying its programming, even to the point of strictly rationing recycled water although it’s freely available aboveground. The Doctor, having learned all he can, tricks Humker, Tandrell and Drathro into holding onto live electrical wires, temporarily stunning them while he escapes; but Drathro sends the L1 robot after him...

Merdeen sends his guards out to search for the Doctor, but privately pulls back Balazar to speak with him. Merdeen knows the truth about the complex and is sick of the cullings; instead of killing people when the population goes over quota, he has been sending them to the surface to survive in the Tribe of the Free. He offers to let Balazar escape, but is unaware that his second-in-command, Grell, is lurking nearby, listening to them. On their way out they run into the escaping Doctor, who reluctantly agrees to help Balazar escape. Merdeen wants to be free from the rule of the Immortal, and the Doctor agrees to help after he’s finished his other business.

The Valeyard points out that the Doctor had the opportunity to extract himself from the situation but deliberately chose to remain.

Broken Tooth uses Glitz’s gun to damage the L1 robot, which temporarily shuts down while Humker and Tandrell desperately attempt to conduct repairs by remote control. The Doctor learns to his horror that Dibber has destroyed Drathro’s black light converter; the chain reaction could cause an enormous explosion, and he now has no choice but to shut down the system entirely. But Broken Tooth, an acquaintance of Balazar’s who was also rescued by Merdeen, refuses to let the Doctor return to the underground complex and instead forces him to accompany the others back to the village.

The Inquisitor finds the scenes of primitive violence distasteful, and the Valeyard takes the opportunity to claim that the Doctor’s predeliction for such violence is well-known. The Doctor protests but his objections are overruled and the evidence continues...

The Doctor and his companions are taken back to the Tribe, where Katryca accuses Dibber of destroying the totem, refuses to listen to the Doctor’s attempt to explain the danger, and has them all imprisoned (except for Balazar, whom she accepts into the Tribe). The Doctor takes the opportunity to question Glitz, who confirms that this planet is indeed Earth, several light years out of position (which is why the relief expedition from Andromeda couldn’t find it when they finally arrived). But before the Doctor can learn exactly what it is Glitz is after, the L1 service robot breaks into their hut and snatches the Doctor, stunning him with an electrical shock and carrying him away. Glitz, Dibber and Peri take the opportunity to escape. Meanwhile, Drathro observes the Tribe of the Free on the images sent back by the L1 robot and concludes that they have destroyed its black light converter; it must take measures to destroy them.

The Doctor points out that much of this testimony is speculative; the Matrix can only access his personal memories as a Time Lord, not those of other people. He learns that advances in technology have made it possible to record events which occurred within range of a TARDIS -- but since his TARDIS is an old model that must mean it’s been bugged...

Katryca leads the Tribe in an attack on the L1 robot, which they manage to destroy, nearly killing the Doctor in the process. Since none of them have ever seen the Immortal, but know him from legend to be a tall creature made entirely of steel, they conclude that the L1 robot is the Immortal and that they have now destroyed it, which means the underground complex is theirs to plunder. As Katryca leads the Tribe to the underground complex, Dibber and Glitz set off back to their ship for the heavy firepower which they suspect will soon be necessary, and Peri rushes to the unconscious Doctor. The Doctor recovers with a splitting headache and Peri brings him up to date on the disastrous situation.

Following the destruction of the L1 robot, Drathro concludes that the Doctor has been sent from Gallifrey to recover the Secrets stolen by the Sleepers, and that to this end he has armed the Tribe of the Free in order to foster rebellion. Humker and Tandrell begin to wonder for the first time what will happen to them if the Doctor succeeds. Drathro isn’t concerned; even if they are killed it will force the Doctor to help it. But by this time it’s obvious that the black light system is approaching catastrophic collapse, and when that happens they will all be killed...

Grell has suspected for some time that Merdeen has been disobeying the Immortal and sending people to the surface, but he has no proof; nevertheless, he confronts Merdeen with his suspicions and threatens to go to the Immortal unless Merdeen allows him to accompany him in his search for the Doctor. Meanwhile, Katryca and her followers enter the complex to find and plunder the Immortal’s Castle. Soon afterwards the Doctor and Peri enter the complex as well, the Doctor determined to shut down the black light system before it explodes and kills everyone. Glitz and Dibber are right behind them, determined to seize the Secrets before the Doctor can get to them --

-- but a portion of this extract has been excised from the Matrix records, as revealing it would be against the public interest. The Doctor is suspicious but doesn’t object...yet.

Merdeen shoots and kills Grell, who dies without ever understanding why Merdeen betrayed the Immortal. Meanwhile, Katryca and her followers arrive at the Immortal’s Castle, where Humker and Tandrell, fearing for their lives, open the doors to let them in and then slip out while the Tribes-people are staring in horror at Drathro. Katryca and Broken Tooth attempt to attack Drathro, but it kills them both with an energy discharge and orders the terrified Tribespeople to wait outside to be culled later. The Doctor, Peri and Merdeen run into the fleeing Humker and Tandrell, and the Doctor questions them about the situation and learns that he may have only minutes to prevent the black light explosion.

The Inquisitor questions the relevance of the testimony, and the Doctor questions the seriousness of the trial; the charges are trumped-up and the points of law non-existent. The Valeyard claims not to be distressed by the Doctor’s childish outbursts and repeats that the chain of events they are witnessing was triggered by the Doctor’s being where he should not.

Dibber, tired of carting heavy weaponry through the underground complex, questions the importance of the secrets Glitz is looking for, but Glitz wearily reminds him that the secrets were stolen from --

Again, a portion of this evidence has been excised, and this time the Doctor does object; but the High Council’s orders stand, and the excised sequence is not heard.

-- the largest information store in the Universe, and as such the advanced technology will be worth a fortune to the correct bidder.

The Doctor arrives at the Castle and convinces Drathro to let him in and listen to him. He insists that the black light system must be shut down, but Drathro refuses to let him do so, since that will mean Drathro’s deactivation. The Doctor tries to argue logically, but Drathro is working from the premise that its "work-units" are there to serve its function and have no intrinsic value of their own; even the fact that humans create robots logically means robots are more advanced, therefore of greater value. As the Doctor tries to think of another tack, Glitz and Dibber arrive and help Merdeen and Peri to break into the Castle through the food distribution chamber. Drathro, concluding that the Doctor was simply trying to distract it, activates the food processing units, nearly killing Peri and the others, but Dibber destroys the processors with his heavy weaponry and blows a hole into Drathro’s control room.

Since the system is minutes away from collapse Drathro sees no reason to waste further energy killing the intruders, and this gives Glitz the opportunity he needs to convince Drathro to return to Glitz’s spacecraft, claiming that they have a fully-functional black light energy system there. Drathro accepts their claim and collects the Secrets, and orders Glitz to restrain the Doctor to prevent him from shutting down the black light system before it can reach safety. Glitz, however, deliberately ties the Doctor with a slipknot, giving him the opportunity he needs to extract himself and his friends. He shuts down the system in the nick of time, and the explosion is contained, destroying only the Immortal’s Castle.

As his black light system collapses, Drathro falls over and explodes, and Glitz and Dibber realize too late that he’s fallen on top of the Secrets, destroying them all. Still, as long as they can salvage the wreckage of the light converter aerial they’ll have made a profit on this venture. As they depart, Humker and Tandrell emerge from the underground, and, upon smelling the wonderful fresh air, realize for the first time that some aspects of life aren’t entirely logical after all. The Doctor, meanwhile, emerges safely from the wreckage of the Castle and advises Merdeen and Balazar to work together with the Tribe to create a new home for humanity; perhaps one day they will even discover the legendary Habitats of the Canadian Goose. But as he and Peri depart, the Doctor ponders the loose ends of the adventure; just what was in that box of secrets, and how and why was the Earth moved so far from its correct constellation?

More petty bickering between the Doctor and the Valeyard leads into the next segment of evidence, as the Doctor angrily realizes that the loose ends from the Ravolox incident are not going to be addressed.

The TARDIS materializes on the garishly coloured planet Thoros Beta in the year 2378, bringing the Doctor and Peri to investigate the sale of advanced phaser weapons to the primitive warlords of Thordon. An advanced civilisation is meddling with the destiny of a less developed one, and the Doctor’s determined to put a stop to it.

But the Valeyard points out that the Doctor is currently on trial for the very same crime...

The tide goes out surprisingly quickly, and the Doctor hears the mechanical pulsing of a tide control unit from a nearby cave and enters to investigate. He and Peri are attacked by a fish creature, and during the struggle the Doctor accidentally fires the phaser he took from Thordon and kills the creature.

The Doctor claims that the phaser went off accidentally in his hand, and the Valeyard doesn’t pursue the matter...yet.

The Doctor finds a machine for extracting energy from the tides, but he’s so wrapped up in studying it that he doesn’t notice until too late that the alarms triggered by his intrusion have stopped sounding. He and Peri are captured by humanoid guards led by Frax, who accuse them of murder. The Doctor picks up on one of Frax’s comments and claims to be part of the scientist Crozier’s group, and Frax takes them to Crozier’s laboratory so they can be identified. The fish creature, the Raak, is taken for dissection to determine whether he regressed genetically.

As they wait for Crozier to see them, Frax becomes suspicious of the Doctor’s claims and demands that he describe Crozier. Instead, the Doctor distracts him and escapes with Peri into the tunnel system. There, they find a man chained to a wall, but the man turns out to be a wolf-mutant who attacks them and then collapses, sobbing piteously for help. The mutant attacks the guards who are pursuing the Doctor and Peri, giving them another chance to escape; and as they hide in a nearby tunnel, trying to catch their breath, they see their old enemy Sil and others of his species being carried through the tunnels by bearers. The Doctor casually mentions that Thoros Beta is Sil’s home planet, horrifying Peri, who wants to leave immediately... but the Doctor isn’t ready to go just yet.

The Valeyard takes this opportunity to point out that a random calculation from the Matrix has indicated that the Doctor’s companions are put in danger twice as often as the Doctor himself. This point should be considered when judgment is passed...

Sil watches as Kiv, the leader of the Mentors of Thoros Beta, prepares contracts for King Yrcanos of Thordon, who has successfully subdued the Tonkonp Empire with the help of the Mentors’ advanced weaponry. The Mentors will continue to sell the Thordonians weapons and scientific technology, and any technological advances made by the Thordonians will be leased with a 40 percent royalty paid back to the Mentors. Their only problem lies in Yrcanos, who only knows how to fight and wage war; he has been sent to Crozier’s laboratory to have his brain artificially pacified, but he is still struggling against the effect of Crozier’s mind-altering machines. Crozier and his assistant Kani are adjusting the machine’s output when Frax arrives with the body of the Raak.

After studying the body and hearing Frax’s story, Crozier heads for the Profit Room with bad news for Kiv. Kiv is suffering spasms of agony as his brain swells within his skull, and Crozier has been conducting experiments in the hope of saving Kiv’s life... but now there may be a further delay. If the Raak’s attack on the two intruders was unprovoked then it may have reverted genetically, which means that Crozier cannot guarantee success if he uses the same techniques on Kiv. And Kiv has given orders that if he dies during the experiment, Crozier will die as well. Frax’s guards are still searching for the Doctor and Peri, and Kiv orders Sil to take charge of the search personally.

As the Doctor convulses under the power influx, Yrcanos recovers and goes on a rampage, smashing the laboratory and the brain control equipment to bits. Sil stops the guards from shooting Yrcanos, as they need him alive to sign contracts, and Yrcanos departs into the tunnels with the Doctor and Peri. The Doctor is in shock from the effect of the machine, while Yrcanos plans to find weapons, rescue his missing equerry Dorf and raise an army to destroy the Mentors. Peri tries to awaken the delirious Doctor.

The Doctor finds he’s unable to remember what happened after the power from the machine flooded through his brain. The Valeyard accuses him of lying in order to avoid facing the consequences of his actions. If he’s telling the truth, he’s in for an exceedingly nasty surprise...

With the brain modification equipment destroyed, the Mentors’ hold over their humanoid servants is weakened. Crozier must repair the equipment before the servants realize their new situation and rebel. To make matters worse, Kiv will soon die unless Crozier can successfully transplant his swelling brain into a larger cranium, but without knowing what happened to the Raak he’s unwilling to risk Kiv’s brain on a potentially disastrous procedure. Kiv blames Sil for losing the Doctor, and orders him to find the fugitives -- or else Sil will share Kiv’s death.

Yrcanos leads the Doctor and Peri to the Mentors’ implantation centre, planning to obtain weapons from the armoury. Sil is there, organizing the search, but as Yrcanos tries to enter unnoticed, the Doctor suddenly shouts out a warning to Sil and Yrcanos is forced to flee. Peri tries to hold the guards at gunpoint, but the Doctor has no intention of escaping, and she flees by herself. Sil is suspicious of the Doctor’s apparent change of heart, but the Doctor claims that he has no reason to risk his life for "a savage and a stupid girl"...

The Doctor refuses to believe he acted in such a self-serving manner, but the Valeyard insists that the Matrix cannot lie and suggests that he throw himself on the mercy of the court. The Doctor refuses, convinced that the evidence will show this was a ploy to fool the Mentors.

The Doctor is questioned once again, and this time convinces Crozier that the Raak’s attack was unprovoked. Crozier’s experiments have failed, and he doesn’t have enough time to repair the damaged equipment *and* find a new way of saving Kiv. The Doctor offers his help and manages to repair the transference machine, and Crozier decides to attempt a temporary transference of Kiv’s brain into a host body to buy time. Sil is still suspicious of the Doctor, and suggests using him as a potential body donor...

Yrcanos finds the cavern of the wolf-man, whom he is appalled to recognize as his equerry Dorf. He snaps Dorf’s chains and leads him away, swearing vengeance. Dorf begs Yrcanos to kill him but Yrcanos urges Dorf to remember his warrior spirit and to turn his rage against the man who changed him... just as Yrcanos is saving his hatred for the Doctor.

Peri hides in the quarters of Matrona Kani, leader of the Mentors’ female servants. Kani, who claims to prefer individuality amongst her own servants, offers to let Peri serve her; but if Peri is discovered as an escaped fugitive Kani will deny this meeting took place. Peri has no choice but to prepare for a life of servitude. Kani takes her servants to a meeting between Kiv, Sil and the Doctor, but the Doctor soon recognizes and reveals Peri. He accuses Peri of trying to poison them, and she is dragged off to be interrogated as the Doctor stands by emotionlessly...

The Doctor claims that this was a ploy; now that he’d helped the Mentors to repair the transference unit, he’d hoped they would trust him to interrogate Peri alone, so they could escape. But the Valeyard informs the Inquisitor that the interrogation in fact took place.

Peri is chained to a rock as the tide comes in, and the Doctor accuses her of participating in a conspiracy with the Alphan servants to overthrow the Mentors. Sil intends to transplant Kiv’s brain into the Doctor’s body and the Doctor must sacrifice Peri to save himself. Kiv orders him not to damage Peri; they have more effective means of interrogation.

The Doctor insists that this scene never took place, but he can’t remember what really did happen...and as the Valeyard and the Inquisitor point out, the Matrix cannot lie. But the Doctor is no longer quite so sure about that.

Peri knocks the gun from the surprised Yrcanos’ hand, and the Doctor flees as Peri insists to Yrcanos that the Doctor wasn’t always like this.

The Valeyard thinks differently, but the Doctor fervently that, although he can’t recall exactly what happened, he’s certain that events didn’t unfold as they’ve seen. The Inquisitor advises the Doctor to accept a trained defender, but the Doctor refuses -- if the Time Lords want him dead he’s not going to trust his defense to them...

The Doctor is found and taken back to Crozier’s laboratory. A donor body has been found in which to host Kiv’s brain temporarily. Kiv is anaesthetized, and before losing consciousness reminds Sil, Crozier and the Doctor that if he dies during the operation they will all be killed as well.

Peri accompanies Yrcanos and Dorf as they attempt to make contact with native pockets of resistance. Yrcanos insists that destiny assures their victory or glorious death, and is appalled when Peri suggests that fate is nothing more than blind chance. He offers Peri flayfish, a food which will give them energy for the coming fight, but foolishly wastes his own energy jealously fighting with Dorf over Peri’s affections. Having rested enough, they set off to search for the Alphan resistance leaders, but when they meet the Alphans they are taken prisoner...

Sil can’t afford to for Kiv to die yet, as he hasn’t learnt all of Kiv’s secrets. At the critical moment, no signs of life are detected in the donor body, and Sil begins panicking and offers Kiv’s bearers bribes if they allow him to escape. The Doctor notes a slight movement of the donor body’s gills, and Crozier stimulates the body with an energy pulse, causing it to begin breathing. The operation has succeeded; Crozier has conquered death. Sil, relieved, offers to show the Doctor a similar miracle of commerce, and the Doctor accompanies him to the Profit Rooms; but moments after they’ve left, Kiv’s new body goes into cardiac arrest...

The Alphan resistance leader, Tuza, prepares to smash the skulls of his prisoners; if their bodies are found intact the Mentors will use them as raw material for their genetic experiments. Peri tries to convince him that they’re all on the same side, and Yrcanos offers to lead the resistance army to victory if they can supply him with weapons and fighters. Tuza is suspicious but agrees to listen, and Yrcanos outlines a plan of battle which convinces Tuza that he can succeed.

Sil studies the stock and commodity markets of the Universe and prepares to reject an application for funding from the salvage company SearchConv Corp. The Doctor advises him to accept; there will soon be a number of wars around the rim worlds, resulting in much debris for SearchConv Corp to claim if they have the equipment to do so. Sil accepts the company’s application and rushes back to Crozier’s laboratory to boast to Kiv. Crozier manages to nurse Kiv through the latest complications and Sil has his bearers take him before Kiv so he’ll be the first face Kiv sees upon awakening. The sight nearly causes Kiv to suffer another cardiac arrest; he is disoriented and takes several minutes to recover. When he does, he’s not pleased to learn that Sil has been engaging in speculation...

On their way to the rebel armoury, Tuza, Peri and Yrcanos encounter an old man stumbling through the tunnels; and as the man dies of extreme old age Tuza recognizes him as Linna, a fellow rebel in his early twenties. And Linna guarded the armoury. Tuza advises caution but this is not the way of the warrior; Yrcanos leads the rebels to the armoury, which has been buried by a suspiciously convenient rockfall. Peri and Dorf both advise prudence, and Yrcanos reluctantly accepts that he must retreat to fight another day. But at that moment another aging rebel claws his way out from under the rockfall and dies, and Tuza realizes that all of his reinforcements have been aged to death. They’ve walked into an ambush, and they are recaptured by Frax.

The Doctor insists that the deaths of the rebels were not his fault, but the Valeyard reminds him that the events which took place were all influenced by his actions. On-screen...

Yrcanos accuses Frax of fighting without honour, rushes him and is gunned down. Tuza is shot while trying to grab weapons from the armoury, and Peri and Dorf are also gunned down trying to escape.

The Valeyard admits that Peri is not dead, and the Inquisitor sharply upbraids him for his use of shock tactics.

Peri and the others recover from the stun blasts. Frax always knew the location of the weapons dump, but also knew that Tuza and his men didn’t have the training to use their weapons properly until Yrcanos showed up. Peri, Yrcanos and Dorf are thrown in a cell together while Tuza is taken to the laboratory. Peri is weary and just wants to go home to people she loves, but her comment leaves her in the position of having to explain to Yrcanos just what "love" is. He explains that on his world, a noble death in battle leads to reincarnation in a nobler body, until a dead king rises to the halls of the gods to fight for eternity. Peri is taken away, as Yrcanos struggles with the strange feelings he has for her.

Kiv begins babbling about the sea, and when the Doctor learns that the new body originally belonged to a fisherman he determines that some of the host body’s brain cells survived sterilisation and are beginning to distort Kiv’s memories. Kiv’s brain must be transferred to a new body as soon as possible. Tuza’s brain is unsuitable for Crozier, and he is sent to the implantation centre. The Doctor is also unsuitable, and Crozier suggests using Peri. The Doctor is clearly concerned, and Crozier offers him time to look for another candidate. But Crozier acts without waiting for him to return; Peri is brought to the laboratory, and Crozier finds her to be a perfect candidate for transference. Peri is strapped to the table and gagged, and Crozier orders Kani to shave her head in preparation...

The Doctor meets Frax at the induction centre and asks for permission to interrogate Yrcanos. Frax takes the Doctor to the cells and gives him a gun to cover Yrcanos...but as soon as Frax has opened Yrcanos’ cell the Doctor holds the gun on him and forces him inside while releasing Yrcanos and Dorf. The Doctor then hands the gun to the puzzled Yrcanos, explaining that he needs Yrcanos’ help. Yrcanos announces that they must also find and rescue his bride-to-be, Perpugilliam of the Browns, and the Doctor is taken aback but promises to rescue her on the way. Frax is eventually found and released by his guards.

The Doctor and Yrcanos overpower the guard at the implantation centre and rescue Tuza, who explains that the implants, inventions of Crozier’s, keep potentially rebellious Alphan slaves under control. The Doctor plans to destroy the implantation control centre, thus causing chaos and providing Yrcanos with a willing army with which to defeat the Mentors. The control centre is guarded, and Dorf is shot by a guard who is himself gunned down by Yrcanos. The Doctor and Tuza continue on ahead to find that Frax had guessed their intentions and is waiting for them. He’s about to take them to Sil for interrogation when Yrcanos comes up behind him and strikes him down. Yrcanos then smashes the implantation centre to pieces, venting his fury at the murder of Dorf, and sets off to rescue his beloved Peri.

Kiv has been given drugs to stabilise his condition during an important business meeting, but still negotiates an important fish concession before remembering that he can’t stand fish. When Yrcanos destroys the implantation controls, the slaves run amok, and in the confusion Kiv passes out and is taken to the laboratory for transference. The Doctor is separated from Yrcanos and Tuza by a crowd of disoriented Alphan slaves, and as he searches for them the TARDIS materializes before him in a beam of light. The Doctor, entranced, enters the TARDIS, which is taken out of time and space and brought to the courtroom of the Time Lords...

The Doctor is horrified to learn that he was taken out of time before he could rescue Peri, but the Inquisitor informs him that he was too late. The High Council themselves were forced to take action to prevent the consequences of the Doctor’s interference...

Crozier has achieved a perfect transference, and more; he has achieved what he set out to do in the first place, and transferred not Kiv’s brain but his mind. Kiv’s consciousness resides within Peri’s brain, and Peri’s consciousness has been erased; as long as Crozier can continue transferring Kiv’s consciousness to new bodies as necessary, Kiv need never die.

Yrcanos and Tuza arrive at the laboratory, but as they rush the guards outside, Time itself slows down around them.

The Inquisitor explains that the Time Lords have suspended them in a time bubble until conditions are suitable for the attack.

Inside the laboratory, Kiv recovers in the body formerly known as Peri, and, reveling in the sensations of a warm-blooded body, he/she orders his former reptilian body to be destroyed. At that moment the Time bubble bursts, and Yrcanos and Tuza enter the laboratory. And Yrcanos, horrified to see what has become of Peri, opens fire indiscriminately, destroying everything in sight...

The court is recessed to give the Doctor a chance to collect himself and prepare his defense, despite the Valeyard’s contention that the Doctor’s apparent grief at Peri’s death is mere play-acting. The Doctor announces that as his defense he will offer an adventure from his personal future, showing that his behaviour improves. He opens an extract from the Earth year 2986. The starliner Hyperion III is on its way to Earth from the planet Mogar, but many of the passengers will not complete the journey...

Professor Sarah Lasky embarrasses herself in reception when she discovers that the reason her luggage was not in cabin 6 was that she was holding her key upside down; she’s in cabin 9. The real occupant of cabin 6 is greeted enthusiastically by an elderly passenger, Kimber, who recognizes him as an investigator named Hallett -- but the man claims that his name is Grenville and that he doesn’t know Kimber at all. After departing the passenger lounge, Grenville slips into the cargo bay, disguises himself as a dockworker and leaves the ship. The ship’s departure is delayed while a late arrival, a Mogarian named Enzu, boards, but it’s soon on its way.

The liner’s stewardess, Janet, brings a cup of coffee to the communications officer, Edwardes, who is trying to contact an unidentified ship near the Hyperion’s flight path. Moments later, someone enters, knocks Edwardes unconscious and transmits a signal to the nearby ship. This is the TARDIS, and the Doctor and his new companion Mel pick up the Mayday and materialize in the Hyperion’s cargo hold. As Enzu watches from the shadows, the Doctor concludes that whoever sent the message to the TARDIS sent it directly to him... but he has a premonition of evil and decides to depart. By that time, however, he and Mel have been detected and they are arrested by the Hyperion’s security guards.

The Doctor and Mel are taken to the bridge to explain their presence to Security Chief Rudge and Commodore Travers, and the Doctor recognizes Travers from a previous encounter. Travers isn’t nearly as pleased to see him; the last time they met Travers became involved in an incident which nearly cost him his ship, and the Doctor was at least partially responsible for placing it in danger. Travers refuses to let the Doctor or Mel leave until he’s learned who sent the Mayday call, and has them restricted to the passenger quarters. Rudge, who is due to retire after this journey, is upset by Travers’ dismissive attitude towards him...

Enzu breaks into the makeshift hydroponics centre in the cargo hold, and steals some silver seeds, unaware that the light from the operations hut is falling on a nearby plant pod which is beginning to pulse. Enzu switches off the light and leaves, and the pod falls back to dormancy. Elsewhere, Lasky’s assistant Bruchner enters the ship’s isolation room, clad in a surgical mask...

Rudge, still suspicious of the Doctor and Mel, leads Mel to the gymnasium and shows her how to use the music system. Lasky is also exercising, and Mel notices how concerned she is when her other assistant Doland reports a break-in at the hydroponics centre. Someone breaks into the gym’s music centre and broadcasts a message for the Doctor into Mel’s headset. The Doctor, meanwhile, convinces Rudge and Janet to let him view the passenger list to see if he recognizes a name, but the lead doesn’t pan out. Mel arrives and tells the Doctor that someone wants to meet him in cabin 6. The Doctor, suspecting that he’s being used as an unwilling agent provocateur, tries -- and fails -- to dissuade Mel from investigating. When they arrive, however, the cabin has been torn apart and the Doctor finds one shoe and a scattering of silver seeds which he takes for later study.

An alarm sounds, indicating trouble at the waste disposal unit, and when the Doctor and Mel arrive they find that someone has knocked out the technician on duty and apparently dumped someone else into the waste disposal chute. A shoe lying nearby matches exactly the one the Doctor found in cabin 6; apparently Mr Grenville has been pulverised and his remains shot out into space. The Doctor and Mel return to the gymnasium, where Mel, unaware that someone is listening in, suggests that they try to find out why Lasky was so concerned about trouble at the hydroponics centre. The Doctor seems uninterested and advises her to investigate by herself...

...except that’s not what happened when the Doctor viewed this material while preparing his defense. This sequence has been altered. The Valeyard insists that the Doctor is presenting a new companion with no introduction to gloss over Peri’s death and that he’s halted the sequence to prevent the court from discovering that Mel too is going to her death. The Doctor denies this and notices that the Valeyard has used exactly the same turn of phrase as he himself used in the altered evidence...

Mel is caught by two guards as she flees from the hydroponics centre, and one of them takes her to the bridge for questioning while the other remains with Edwardes’ body. But something emerges from one of the plant pods and approaches the unsuspecting guard...

The Valeyard points out that once again the Doctor callously sent his companion into a life-threatening situation, but the Doctor insists that the evidence has changed since he reviewed it. However, he has no way of proving his allegation and is forced to continue...

The Doctor is summoned to the bridge to vouch for Mel’s innocence, and while there he and Mel learn that both Edwardes’ body and the guard who remained with it have vanished. They return to the passenger lounge, passing the isolation room on the way; the Doctor notes the presence of a guard and wonders if he’s there to keep people out of the isolation room or to keep something in. Professor Lasky is already in the lounge when they arrive, and Mel suggests showing her the seeds from cabin 6 to see whether she can identify them. Lasky accuses the Doctor of stealing them, but the misunderstanding is soon sorted out; these are the Demeter seeds which were stolen from the hydroponics centre, but why would Grenville want to steal them? Elsewhere, Doland emerges from the isolation room with the shattered remains of a tray of food...

Enzu returns to the cargo hold to investigate the wreckage of the hydroponics centre, and finds a leaf stuck in a nearby ventilation grille. Doland and Bruchner arrive and discover what’s happened, and Bruchner begins to panic; he’d advised against taking their experiments to this level, and only he understands the terrible force they’ve unleashed. Doland dismisses his fears as paranoia and claims not to hear anything when Bruchner catches a glimpse of Enzu slipping away.

Travers, desperate to get trained investigators on board, has the ship alter its course, shaving 72 hours off its travel time by skirting closer to the Black Hole of Tartarus. He reports the change to the passengers in the lounge, and the Mogarians Atza and Ortezo switch on their translators in order to complain about the danger. The Doctor watches as Enzu joins in the conversation, as the Mogarians reveal their deep distrust of Earthlings, who are stripping Mogar bare of its natural resources.

The Valeyard questions the relevance of this political discussion, but the Doctor points out that he’s missed a vital detail in the scene. Someone else is about to die...

The Doctor and Mel ponder their next move while Janet hands out drinks to the passengers. Enzu suddenly begins choking on his drink, and the Doctor tries to remove the helmet of Enzu’s environmental suit to help him. He is restrained by Travers and Rudge, as Enzu will die if exposed to human atmosphere, and by the time the Doctor’s able to explain that Enzu isn’t really a Mogarian it’s too late to save him. The Doctor removes Enzu’s helmet to reveal the face of Grenville, whom he recognizes as a former acquaintance, an investigator named Hallett. When the Doctor learns about Kimber’s earlier encounter, he realizes what happened; Kimber accidentally blew Hallett’s cover and Hallett was forced to fake his own death and board the ship under a different identity in order to continue his investigation. Rudge demands to know how the Doctor knew the dead man wasn’t really a Mogarian...

So does the Valeyard, and the Doctor replays the Mogarians’ earlier conversation and points out that, while Atza and Ortezo had to activate artificial translators to be understood, "Enzu" didn’t. Obviously it was Hallett who sent the distress call to the Doctor, and the Doctor claims that this is what justified his involvement.

The Doctor is now determined to find out who killed his friend Hallett, and Mel suggests that Hallett left the Demeter seeds for the Doctor to find in order to point him to the hydroponics centre. The Doctor finally agrees to accompany her to the hydroponics centre, where he compares a leaf he took from Hallett’s pocket with the empty pods he finds there. Professor Lasky’s field is the breeding of domesticated plants and animals; so what was in the pods before they germinated? The creatures which emerged from the pods are now loose within the infrastructure of the ship...

Bruchner also fears what’s been unleashed and tries to warn his colleagues of the danger, but they insist he’s overreacting. However, one of the pod creatures has emerged into the bathroom of Kimber’s suite, and it attacks the old man and stings him to death with a venomous thorn.

The mutating woman begs the Doctor to "stop Lasky", but before she can say anything further, Lasky, Doland and Bruchner arrive and force the Doctor and Mel out. Doland angrily explains that the mutant is his former assistant Ruth Baxter, who was exposed to virulent plant DNA during a cross-pollination experiment; they’re taking her back to Earth for treatment. Rudge then arrives and arrests the Doctor for triggering the false fire alarm, and he is taken to the bridge to explain his actions to the Commodore. Travers has already contacted the authorities on Earth, who have refused to explain what Hallett’s mission was; by the time they go through channels and authorise releasing the information it may be too late. The Commodore now has no choice but to begin co-operating overtly with the Doctor’s investigation. Before leaving the bridge, the Doctor notes that they’re approaching the dangerous Black Hole of Tartarus.

Janet reports to Rudge that Kimber didn’t emerge from his cabin during the fire drill, and they enter and find the cabin empty. Rudge and Janet leave to begin searching for the missing passenger, and Mel slips into Kimber’s cabin and discovers a leaf caught in the ventilation grille. Kimber’s body has been placed with the bodies of Edwardes and the missing guard by the plant creatures, who also kill the isolation room’s guard.

Mel tries to speak with Lasky, hoping she can identify the mysterious leaf, but Lasky refuses to interrupt her workout schedule. Doland finds Lasky and tells her that Bruchner, upon hearing of Kimber’s disappearance, has begun destroying all of his and his fellow scientists’ research. As Lasky goes to talk some sense into Bruchner, Mel tries to question Doland, who tells her that the empty pods contained giant fruit which was left behind on Mogar. Left alone in the gymnasium, Mel hears whispers from the ventilation grille, and uses one of the music headsets to amplify the whispering and copy it onto a tape in the music room. She hears the Vervoids planning to kill all animalkind, but she is then attacked by someone who anaesthetizes her and hides her body into the waste disposal cart.

The Doctor, searching for Mel, enters the gymnasium just as an attendant leaves with the cart. He finds and listens to the tape, and, hearing Mel’s scream and his own subsequent greeting to the attendant, realizes what’s happened and rushes to the pulveriser just in time to rescue Mel. By the time he and Mel return to the gymnasium, however, the tape has been removed. Mel suggests that Janet could be a suspect and offers to search her room, while the Doctor returns to the hydroponics centre, certain that it’s the key to what’s going on.

Rudge, unable to locate Kimber, is forced to report the disappearance to the contemptuous Commodore. He’s also forced to explain what’s happening to Atza and Ortezo, who seem to have some sort of hold over him. Later, Atza accidentally spills a drink over Janet, who goes to change. Mel is already searching Janet’s cabin when she hears someone approaching and is forced to hide in the shower. But it’s not Janet -- it’s a Vervoid, which begins tearing the cabin to pieces when it finds it empty. Elsewhere, the communications room has been smashed to bits, and the Doctor is standing amidst the wreckage with an axe and a smile...

Again, the Doctor insists that the evidence has been changed. He didn’t destroy the communications unit; the killer did, to prevent Travers from getting word from Earth authorities. The Matrix has been altered -- but the Doctor has no other source of evidence and no way to prove his claim.

By the time Lasky arrives at the hydroponics centre Bruchner has destroyed all of their research. She tries to reason with him, reminding him that knowledge can’t be unlearned, but realizes too late that her words have been taken the wrong way -- Bruchner now realizes that everything he wishes to destroy is trapped aboard this ship. Bruchner overpowers Lasky and flees, and the Doctor arrives moments later and finds Lasky recovering. She doesn’t listen to the Doctor’s attempts to warn her of what she’s created, and rushes off to find and stop Bruchner, the Doctor following.

The Vervoids, desperate to stop Bruchner, assemble near the bridge, spewing toxic marsh gas from their mouths. The Vervoid in Janet’s cabin also departs, giving Mel the chance she needs to escape. The duty stewards, meanwhile, burn through the bridge doors, only to find the bridge filled with marsh gas; Bruchner is dead but the Commodore has no way of getting to the controls to alter course away from the black hole. Rudge, however, comes up with the solution -- he contacts Atza and Ortezo. As they’re already confined to environmental suits, they aren’t affected by the toxic atmosphere within the bridge and are able to pilot the ship to safety. However, once the toxic gas has cleared they refuse to give up control of the ship, and Rudge holds Travers, Lasky and the Doctor as hostages...

As Rudge leads his hostages back to the lounge, the Doctor notices Mel approaching and manages to communicate a warning to her without letting Rudge know about it. Mel warns Janet and Doland of the danger and they escape from the lounge moments before Rudge arrives. The Mogarians intend to steal the consignment of minerals which they believe was plundered from their planet, and Rudge, bitter about being put out to pasture, has agreed to help to ensure a comfortable retirement for himself.

Since the communications room has been smashed, Mel is unable to send a Mayday call, and she tells Janet to arrange for the guards to attack the lounge while she tries to get a warning to Rudge’s hostages. She climbs through the air ducts and manages to warn the Doctor of her intentions, but he tells her to attack the bridge instead; the Mogarians are peaceful creatures who don’t want to resort to violence, while Rudge is more dangerous. Mel returns to tell Janet and Doland of the change in plans, but by the time they reach the bridge Atza and Ortezo are already dead; someone has surprised them and flung acid onto their suits, exposing them to the ship’s oxygenated atmosphere (toxic to Mogarians).

Mel, Doland and Janet take the Mogarians’ helmets to the lounge to show Rudge that the hijack has failed, and he panics and flees -- only to be found and killed by Vervoids. Meanwhile, the Doctor prepares to put an end to the murder mystery, and after secretly passing the Commodore a note and arming himself, sets off to search Doland’s cabin for the missing tape while sending Mel to search Lasky’s locker in the gymnasium. Doland finds the Doctor and reluctantly offers to show him another secret location in the hydroponics centre where Lasky keeps her belongings... but while there, he overpowers the Doctor and takes his phaser.

The Doctor admits that he already knew Doland was the killer. Edwardes was killed by someone with access to the hydroponics centre; Hallett was poisoned and Mel anaesthetized by someone with access to the medicines in the isolation room; and when the Mogarians were killed Bruchner was dead and Lasky was being held hostage in the lounge. Doland has made a private deal with a consortium on Earth to sell the Vervoids as slave labour, and is willing to kill to ensure that they reach Earth safely and secretly. He realizes too late that the Doctor disarmed the phaser and explained everything to the Commodore in advance. Doland is arrested and taken to the brig, but on the way he and his guard are ambushed and killed by Vervoids. Lasky can’t understand why her creations are killing people, until the Doctor points out what Bruchner had already realized; the Vervoids are operating on an instinctive level, and as plants, they regard animal life as their natural enemies. Travers concludes that they have no choice but to fight for their survival and orders the Doctor to assist.

The Doctor points out the crux of his defense; his assistance was specifically requested by the chief authority aboard the ship. The Valeyard decides to let the evidence play itself out...

The Vervoids attack in force, killing the waste disposal technician and trapping Janet and several ship’s officers in the lounge. The Doctor, Mel and Lasky head for the hydroponics centre to synthesize a herbicide, only to find that the Vervoids have destroyed the chemical store. The Vervoids block the exit from the cargo hold, and the Doctor and Mel flee through an air duct while Lasky tries to reason with the Vervoids. But the Vervoids won’t listen, even to Lasky, and kill her. The Doctor and Mel find a pile of bodies collected by the Vervoids, who are instinctively building a compost heap, and the Doctor realizes what he must do.

The Doctor and Mel return to the bridge, where the Doctor forces Travers to admit that the consignment of minerals which triggered the attempted hijacking includes vionesium. When exposed to oxygenated air, vionesium reacts violently, producing carbon dioxide and concentrated light, and is thus perfect as a weapon against the Vervoids. Travers shuts down the ship’s life support and lights, driving the Vervoids back into the air ducts, while the Doctor, Mel and the guards wait by the Vervoid "compost heap". Once all the Vervoids have assembled, the humans release the vionesium, and the chemical reaction accelerates the Vervoid life cycle, causing them all to age and decay to mulch within seconds. Having saved the day, the Doctor and Mel depart from the ship, as Travers thanks the Doctor for his help and asks him not to come back.

All evidence has been presented, and before the verdict is passed, the Inquisitor summons the Keeper of the Matrix to answer the Doctor’s claims that the Matrix has been tampered with. This, the Keeper insists, is impossible; he holds the only key to the data store, and it never leaves his possession except in the hands of qualified personnel during service checkups once a millenium. The Doctor insists that somehow, the Matrix has been penetrated, the evidence altered, but he is unable to substantiate his claims...until Sabalom Glitz and Mel unexpectedly arrive in the courtroom, and the Master appears on the Matrix screen with a duplicate Matrix key -- proof positive that the Matrix can be infiltrated. The Master has been watching the trial with amusement but has now intervened, sending the Doctor witnesses to substantiate his claims of malfeasance -- for the Master is not prepared to countenance a rival...

The Valeyard, clearly unnerved, requests a recess, but the Inquisitor overrules the request and allows the Doctor to question the witnesses. The Doctor finally gets the chance to ask Glitz what was in the box of secrets from Ravolox... and learns, to his shock, that it contained secrets the Andromedans had stolen from the Matrix. After finding a way in, the Andromedans set up a base on Earth in order to prevent the Time Lords from tracing their home world, but the Time Lords used a Magnetron to draw the Earth and its constellation out of position, causing the solar fireball which ravaged the planet and causing the Andromedan recovery mission to miss Earth. The Master fills in the remaining pieces; the planet was renamed Ravolox to cover up the High Council’s actions, and when the Doctor stumbled across the mystery, the Council struck a deal with the Valeyard to place the Doctor on trial and dispose of him by using altered evidence from the Matrix. The Doctor, furious at this evidence of the Council’s corruption, is even more horrified when the Master gleefully reveals the Valeyard’s true identity -- he is an amalgamation of the Doctor’s darker natures, drawn from between his twelfth and final regeneration, and he seeks the Doctor’s remaining incarnations for himself...

The Valeyard flees from the courtroom and uses a duplicate key to pass through the legendary Seventh Door, physically entering the Matrix itself. The Keeper uses his key to grant the Doctor access to the Matrix, and the Doctor drags Glitz in with him. They find themselves in a virtual reality construction of a dark Victorian courtyard, Dickensian gothic, with disembodied voices singing children’s songs and laughing madly in the background. They’re now in the Matrix, trapped in a construction of the Valeyard’s -- the "Fantasy Factory" (proprietor J.J. Chambers). A spear is flung from the Factory, nearly piercing Glitz through the chest, but he survives thanks to his armoured vest. Glitz has had enough and wants to go, but the Doctor points out that if the Valeyard succeeds in disposing of him, he’ll then go after Glitz to dispose of the only witness. Glitz reluctantly accompanies the Doctor into the Fantasy Factory.

The Inquisitor demands to know how much of the evidence was falsified, and the Master concedes that most of what they saw was the truth in order to make the lies more convincing. Peri, however, is still alive, and is in fact Yrcanos’ queen. He admits that he interfered in the trial not out of concern for the Doctor; in fact, he’s hoping that if the Valeyard and the Doctor are set against each other, the battle will end in both their deaths. The Master’s more concerned with the larger implications of the trial; by exposing the truth of the High Council’s corruption he will rock Time Lord society to its very foundations...

Glitz arrives too late to rescue the Doctor, who vanishes beneath the surface of the beach. But the Doctor rises back up from the sand without a mark on him, reminding Glitz that they’re in a virtual reality and nothing is as it seems. The Valeyard appears on the beach to taunt the Doctor again; once he has disposed of his moral side, he will be free to act on his base desires, and with access to the Matrix there will be nothing he cannot achieve. The Valeyard vanishes and the Doctor and Glitz are pursued up the beach by a cloud of nerve gas. In the courtroom, Mel demands that the Time Lords help the Doctor, but the Inquisitor and Keeper refuse to act and restrain her when she tries to grab the Key from the Keeper.

The Doctor and Glitz are rescued by the Master, whose TARDIS takes the form of a beach hut. The Master ushers Glitz out of the control room and triggers a barrage of sound and light which causes the Doctor to retreat into catatonia. The Master’s TARDIS then takes on the form of a statue of Queen Victoria and materializes in the courtyard of the Fantasy Factory, where the Master tries to use the comatose Doctor to lure the Valeyard out into the open; but the Valeyard’s cloak deflects the beam from the Master’s TCE, and he throws exploding quill pens at the Master and Glitz, driving the Master off and knocking Glitz unconscious.

The Doctor recovers to hear Mel calling him, and she leads him out of the Matrix and back to the courtroom so he can clear his name. The Inquisitor questions her about the destruction of the Vervoids and she confirms that it really occurred... and the Inquisitor has no choice but to find the Doctor guilty of genocide and have him taken away to be executed. In fact this is yet another illusion created by the Valeyard, and when the real Mel realizes the Inquisitor isn’t going to act to stop the Doctor’s execution, she overpowers the Keeper, grabs the Key and lets herself into the Matrix to save the Doctor. She discovers too late that the Doctor was aware of the illusory nature of the verdict and was playing along in the hopes of reaching the final confrontation with the Valeyard.

The Master returns and collects the recovering Glitz, and offers him riches beyond the dreams of avarice, even Glitz’s, if he betrays the Doctor to the Valeyard. Glitz enters the Fantasy Factory and searches the junior Mr Popplewick’s office, and finds the box of Matrix archives, the original of the duplicate which was destroyed on Ravolox. The senior Mr Popplewick holds him at gunpoint, and Glitz strikes a deal with him.

The Doctor and Mel search the senior Mr Popplewick’s office; the Doctor is convinced that there’s something else going on here, as the lengths to which the Valeyard has gone to kill him are far too elaborate. He finds, written in his own handwriting, the names of all of the Time Lords attending his trial, all crossed out. Glitz arrives, holding the senior Mr Popplewick at gunpoint, and announces that he’s convinced Popplewick to lead them to the Valeyard. Popplewick leads them out of the Factory and across the courtyard to another buliding, but as the Doctor and Mel enter, Glitz and Popplewick exchange the gun and the Matrix archives. Popplewick tries to shoot Glitz as he leaves, only to find that Glitz removed the bullets from the gun. But before Glitz can go, the Master reappears and forces Glitz to bring the Matrix archives into his TARDIS.

Popplewick finds the Doctor and Mel gazing with awe at a vast Victorian engine, and offers to find Chambers; the Doctor gives Popplewick a chance to get clear, and then grabs a length of rope and follows. He finds Popplewick closing a door marked "DANGER", and ties him up and removes his rubber mask to reveal that "Popplewick" is in fact the Valeyard in disguise. Mel opens the door to reveal a Particle Disseminator, a weapon capable of destroying everything down to subatomic particles, and the Doctor realizes that the Valeyard intends to fire it through the Matrix screen into the courtroom, killing the guardians of Gallifreyan law. He sends Mel back to warn the Time Lords while he tries to shut down the Disseminator.

Anarchy erupts on Gallifrey and the corrupt High Council is deposed, and the Master prepares to step in to fill the power vacuum. He snaps the Matrix archives into place in his TARDIS, preparing to seize control, but discovers too late that the box which Popplewick gave Glitz is in fact a Limbo Atrophier which freezes both him and Glitz into position. Mel bursts into the courtroom to warn the Time Lords of the danger, but as they begin to evacuate the Matrix screen explodes. The Doctor is able to shut down the Disseminator in the nick of time, but in doing so causes a feedback of energy into the Matrix itself. The Valeyard frees himself and attempts to correct the Doctor’s mistake, but it’s too late, and the Doctor is forced to flee, leaving the Valeyard apparently trapped in the Fantasy Factory as this portion of the Matrix breaks down and explodes.

The Doctor returns to the courtroom and politely asks the Inquisitor what her verdict is, and the Inquisitor gratefully dismisses all charges and tells him of Peri’s survival. She suggests that he stand for election when a new High Council is elected, but the Doctor turns down the offer and advises the Inquisitor to stand in his place. He also suggests that, once freed from the Matrix, Glitz should be treated with leniency, as he’s not beyond redemption; but they can do what they like with the Master. He and Mel return to the TARDIS and depart, as the Doctor realizes to his horror that Mel intends to get him back on his exercise routine immediately.