Terror of the Vervoids (Trial of a Time Lord, parts 9-12)
The Doctor finally gets his chance to present his defense in his trial. He presents an adventure from his own future, in which he and new companion Melanie are summoned to a posh space luxury liner by an anonymous distress call. While the ship’s captain – who has met the Doctor on a previous occasion – and the incompetent chief of security initially regard the Doctor and Mel as stowaways, they find themselves with other problems when murders begin to occur aboard the ship, and three scientists are being very secretive about their hydroponics experiment in the ship’s cargo deck. As more passengers die mysteriously, the ship’s captain asks the Doctor to help – but, according to the evidence, the Doctor isn’t really all that helpful…which isn’t how he remembers the story.
written by Pip Baker & Jane Baker
directed by Chris Clough
music by Malcolm ClarkeCast: Colin Baker (The Doctor), Nicola Bryant (Peri), Bonnie Langford (Melanie), Michael Jayston (The Valeyard), Lynda Bellingham (Inquisitor), Honor Blackman (Professor Lasky), Michael Craig (Commodore Travers), Denys Hawthorne (Rudge), Yolande Palfrey (Janet), Tony Scoggo (Enzu/Grenville), Malcolm Tierney (Doland), David Allister (Bruchner), Arthur Hewlett (Kimber), Simon Slaters (Edwardes), Barbara Ward (Mutant), Sam Howard (Atza), Leon Davis (Ortezo), Hugh Beverton (Guard), Mike Mungarvan (Duty Officer), Peppi Borza (First Vervoid), Bob Appleby (Second Vervoid), Barbara Ward (Ruth Baxter)
Broadcast from November 1 through 22, 1986
LogBook entry & review by Earl Green
Pompeii, Italy, 1980 A.D.: A UNIT operative hastily takes charge of an archaeological dig at Pompeii when, in the ruins of the city that died in the eruption of Vesuvius, an inexplicable anachronism is unearthed – a British police telephone box, preserved in the ancient ash. The oddity is removed from the site and put in top security storage by UNIT. The Doctor is summoned to investigate, but – in his fifth incarnation – he chooses not to enter the police box. 
The Doctor reluctantly answers a distress call from the planet Generios (in the Generios system, which is nestled away quietly in the constellation of Generios). When he arrives, though, he finds he’s surplus to requirements – the people of Generios are celebrating their victory over the evil Skelloids, a victory they say was engineered by that legendary time traveler known as the Doctor! Mel chalks it up to one of the Doctor’s other incarnations, but the Doctor isn’t so sure. When he runs into the man the people of Generios have hailed as a hero, the Doctor is even more certain that this man isn’t one of his future selves – this “Doctor” travels around the universe in what is essentially a transmat disguised as a Porta-Loo, and generally being far too chummy with his buxom sidekick Sally Anne. But when a new alien menace threatens to destroy Generios – this time decidedly more real than the fake Doctor’s equally fake holographically-projected Skelloid invasion – the planet must look to the Doctor (the real Doctor) for help.
The Doctor and Melanie arrive at a most inopportune time aboard space station Dark Space 8, and the Doctor is mistaken for the replacement for the station’s recently-deceased commander – a role into which the Time Lord steps eagerly, to Mel’s dismay. Dark Space 8 is playing host to an intergalactic pop song contest in a matter of days, and station security is stepped up accordingly – but apparently not enough, as one of the contestants turns up dead. As more murders occur, the station’s crew is helpless (and clueless), and when one of the suspects seems to have an unnatural hold over the Doctor, Mel worries that she is on her own in solving the mystery…
…just then, the “other” Doctor and Melanie arrive on the human colony planet Puxatornee, discovering that the alien Slithergees have all but taken over, using humans are seeing-eye dogs and servants, and even edging human traditions, history and beliefs out of the humans’ own teachings by way of claiming rampant anti-Slithergee discrimination. Two terrorists, Stewart and Reed, are out to restore the balance and put the humans in charge again, and when they discover that the Doctor and Mel are time travelers, they force the TARDIS crew at gunpoint to take them back in time to change history. But the history they bring about is one where the Slithergees were refused permission to settle in the Puxatornee system, resulting in a war that left the planet permanently contaminated. Stewart and Reed are killed, and the Doctor makes a hasty exit, worried about encountering his and Mel’s counterparts from the divergent timeline that has been created. Just then, the “other” Doctor and Melanie arrive on the doomed planet Puxatornee, where two soldiers, Stewart and Reed, wish to change history so the human-Slithergee war never fatally polluted Puxatornee. When they discover that the Doctor and Mel are time travelers, they force the TARDIS crew at gunpoint to take them back in time to prevent these events. But the history they bring about is one where the Slithergees were granted permission to settle and slowly took over. Stewart and Reed are killed, and the Doctor makes a hasty exit, worried about encountering his and Mel’s counterparts from the divergent timeline that has been created…
During his trial, the Doctor struggles with the Valeyard and becomes trapped in the Matrix as Melanie watches in horror – and the other Time Lords, including a newly elected Lord President, watch with distant interest and no desire to interfere. Mel insists on trying to rescue the Doctor, but finds no interest from the Time Lords, who plan to watch the unfurling of the Doctor’s history with detached curiosity should the Valeyard win. And indeed the Valeyard does win, but he doesn’t limit himself to the Matrix – and he doesn’t stop with killing the Doctor. The Valeyard interferes with time and destroys Gallifrey itself, and even goes back and kills the fourth Doctor en route to Logopolis. That act begins to unravel the Valeyard’s own history, however – and in trying to go back and restore his past timeline as the Doctor, he may destroy the web of time itself.
An attack on a space cruiser they’re visiting forces the Doctor and Melanie to evacuate by any means necessary. Mel manages to make her way to an escape pod, which takes her to a research colony on the planet Lethe. The Doctor and the TARDIS, however, are captured by the Daleks, who offer to send the Doctor to Lethe too…so long as he reports back on what their creator, Davros, is doing there. When the Doctor arrives, he finds that Davros has managed to conceal his appearance and is calling himself Professor Vaso – and worse yet, he has unearthed specimens of one of the Daleks’ worst enemies, the Mechonoids. Davros has quietly set up self-replication facilities for the Mechonoids, aware of their potential for battling the Daleks, claiming that he hopes to atone for his past by ridding the universe of his creations. But even with this claim of a noble mission, the Doctor sees Davros up to his old tricks, leaving a trail of death in his wake. But when the Doctor fulfills his end of the bargain and alerts the Daleks, who still want to capture Davros and try him for crimes against them, things only get worse, with an entire colony of innocent bystanders caught in the crossfire of a new Dalek-Mechonoid war.
The Doctor and Melanie arrive at the National Foundation for Scientific Research just prior to a public ceremony marking the Foundation’s 100th anniversary. Mel’s eccentric uncle, John Hallam, is not just a member of the Foundation but actually lives on the grounds. During the ceremony, involving the burial of a time capsule, it is discovered that something else has already been buried there. When the Doctor and Hallam examine the object, it causes an explosion in another one of the Foundation’s laboratories – one where a rather bored Melanie is reading through Hallam’s records of their family history. Melanie is missing when the Doctor and Hallam try to come to her aid, and the Doctor strongly suspects that the mysterious object has catapulted her back in time. He also thinks that her time journey may have been directed by her thoughts at the time, so the TARDIS homes in on the sprawling Hallam estate in 1782. That leaves only a few rather significant problems: in Melanie’s timeline, six months have passed since her arrival, and in that time, she has been heavily drugged by a family doctor who feels that her ramblings about being from the future are a sign of dementia. Worse yet, with no sign of rescue from that future, Mel has started to believe that she is who her ancestor, Henry Hallam, tells her she is: his future wife, and therefore her own ancestor.
Mel is alarmed when the TARDIS materializes without the Doctor at the controls. After leaving her on Earth briefly to take care of unspecified business, he has vanished without a trace, leaving her a holographic message in the TARDIS instructing her to follow his trail to the Klyst Institute, a grim-looking mental hospital. Rather than risk trying to fly the TARDIS herself, Mel enlists the reluctant help of a rough-and-tumble cabbie who helps her as she breaks into the Institute. There, she finds the Doctor – but his mind is gone, and he speaks in almost nonsensical phrases. Mel and her new friend try to escape with the Doctor, but they find that the Institute is no longer on Earth, having transported itself to an asteroid in an instant. The Institute also seems to be bigger inside than out, and other aliens (and humans) have been captured for horrific mind-transfer experiments. Are Time Lords operating in secret on Earth? And if so, are they renegades like the Doctor…or something darker interference in human history going on with the Time Lords’ full knowledge?