It is the twenty-sixth episode overall.
The episode begins with an unspecified colony (3 million years in the past, and probably Io given the similarity) and a figure appears in front of Thomas Allman saying that he is unworthy of having existed, he then proceeds to erase him from history and replace him with "those never given the gift of life". Once complete, this figure "deletes" the physical form of the original version of Thomas Allman and then disappears.
While in Starbug, after discussing the illogical of the Trojan Horse maneuver after Lister is reading the comic book version of Virgil's Aeneid (which according to Kryten has remained faithful to the original text; including many "fzzzt!"s, "zap!"s and "kapow!"s). Starbug is on auto-pilot (being piloted by Holly), on a return course back to Red Dwarf, then Lister's vocal chords are controlled, he is being made to speak in the figure's voice, he announces that he is the Inquisitor and that their ship is under his control, he is returning them to Red Dwarf to face judgement to justify their existence. Once released Kryten tells them on the astro folklore of the Inquisitor, a self-repairing simulant who survived to the end of time itself, who concluded that there is no god or afterlife of any kind and that the purpose of existence is to live a worthwhile life, so after constructing a time machine (in the form of a Time Gauntlet) he travels through time and space, judging each sentient lifeform, erasing those who wasted their lives and replacing them with those who never had a chance of life (the unfertilized ova, the sperm that never made it).
They return to Red Dwarf and the "inquisition" begins with Rimmer, who is shocked to find out that the judge is himself (according to the Inquisitor, it's the only fair way to judge others), after trying to lie to himself unsuccessfully, his case involved saying that he is nothing, which is up compared to what he started with, the Cat's case is a shallow one, which astonished himself. Kryten honestly replies that despite his selfless nature it is not a result of a code of conduct he has decided for himself but the programming he received, and the validity of his deeds is questionable (nor does it help when Kryten asks what right the Inquisitor has to appoint himself the final judge of all life). Lister tells himself to "spin on it!" when he is told to justify himself, blowing off responsibility as he has always done. Lister and Kryten are considered unworthy of existance (Rimmer and the Cat acquitted themselves as they were shallow and selfish creatures), after separating Lister and Kryten from the others, he erases them from time, but before deleting their physical forms, a future version of Kryten slices off the Inquisitor's hand with a holo-saw and throws them the gauntlet, after telling them of details of the "final confrontation", future Kryten is then killed.
Present Kryten and Lister escape, and once they are found by Rimmer and the Cat, they realise that they don't exist anymore, after Lister convincing Rimmer that he knows him, they are escorted by them and the new Lister and new Kryten. The gang are then ambushed by the Inquisitor as they exit a lift, resulting in the deaths of these alternate counterparts. The rest get to the transport deck via the new Lister's dead hand, after thinking of a plan, they confront the Inquisitor joined by Rimmer and the Cat (who are also killed by the Inquisitor), after a fight, Kryten goes back in time to sacrifice himself, so that they get into the mess they're in, in the first place.
Lister ambushes and dangles the Inquisitor over a chasm, threatening to kill him, then he saves him, reasoning that if Lister is erased, he won't be there to save him and he'll die - but the Inquisitor reasons that he can erase him quite safely as he wouldn't exist to threaten his life in the first place. It turns out that Kryten, under Lister's instructions, reprogrammed the Time Gauntlet to backfire and erase the wearer, if the "erase" function is used, which erases the wearer. It works, undoing all of the Inquisitor's work from the time-line, and restores Kryten, Rimmer and the Cat to life. Kryten offers a high-five in which Lister decides to "give him fifteen" (two hands and the alternate Lister's hand, while it's still there).
As available for viewing on the Series V DVD:
- Three extensions to the "Trojan Horse" discussion. They include Lister mocking the Greeks, Rimmer mocking Lister's historical knowledge, and Kryten talking of Silicon Heaven while Rimmer shows him the manual that shows Kryten has installed a "silicon heaven belief chip".
- As the Inquisitor remotely takes over Lister's body, ordering Starbug to turn around, Rimmer comes up with a plan to outwit the rogue droid - that is, knocking Lister unconscious. As the Inquisitor then speaks through Lister, telling them that he can erase them from history without any damage to causality, the Cat hits Lister with a shovel, and a second time when Lister goes to get back up. As Kryten protests, the Cat then hits Kryten on the head with the shovel. Rimmer and Cat seem smug believing that they have outwitted the Inquisitor, who then takes over the Cat's body. Then Rimmer's, then Kryten's. The Cat hits Kryten again with the shovel.
- Lister and Kryten face death in a number of trimmed chase scenes with the Inquisitor. These also include extended dialogue in the meeting with the alternate Lister and alternate Kryten.
- After Holly fails to recognise Lister and Kryten, there was a short sequence of Lister saying that they no longer exist in this timeline, with Kryten telling Lister that "More accurately, we don't ever have existed here anymore." However, Craig Charles and Robert Llewellyn simply could not get through the scene without corpsing or flubbing their lines, and so it was truncated to just Lister realizing that they have been erased from history.
- As originally shot, the Inquisitor was to remove his mask to reveal a pale, thin man with red around the eyes, black lips and black veins across his face. However it was decided this was not the stuff of campfire horror stories it was intended to be and so was dropped, leaving an air of mystery around the character. The original ending was later re-shot with mostly identical dialogue - but in the re-shoot the Inquisitor kept his visor down.
- The removal of The Inquisitor's existence at the end of the episode triggers major changes in the time-space continuum. By undoing all of his work (remembering all the people who had been erased by him previously), the timeline would have changed dramatically, although it is never indicated to what degree this would have impacted the crew (certainly there's no indication, for example, that restoring people to history prevented the accident). This is one of several key moments in the series, however, where a major change to the timeline does occur, which may help in explaining continuity inconsistencies between seasons.
- Thomas Allman isn't given a chance to justify his existence before being replaced (at least, not on-camera, in which case it's strange he doesn't remember his "trial" while Lister and Kryten do prior to their deletion).
Interesting, funny or relevant dialogue in the episode
- The Inquisitor to Thomas Allman: Thomas Allman, you have been found unworthy of having existed...
Thomas Allman: Is that you mother?
- The Cat: What happened to him (Lister)? His voice finally break?
- Rimmer: All those charity telethons where I used to ring in and pledge donations. If I had known all this (that the object was to lead a worthwhile life) I would have given them my credit card number.
- Inquistor: Justify your existence.
Cat: I have given pleasure to the world because I have such a beautiful ass!
- Lister: Why should we take any notice of some half-crazed, rogue robot who's appointed himself judge and jury to the whole of humanity? Why should we kowtow to his judgement?
The Inquisitor speaking through Lister: Because I have the power to snap your body in two like a dry reed!
Lister: Good answer, man, good answer.
- Kryten: Eniggggggggggggg...
- Lister to new Lister: We're sperms in law. The only difference is on of us did crawl, the other breaststroke...
- For this episode, Red Dwarf writers Doug Naylor and Rob Grant were heavily inspired by the film "The Terminator" and the works of Harlan Ellison. Red Dwarf musician Howard Goodall composed the Inquisitor's theme to be reminiscent of the synthesized theme to The Terminator.
- The writers originally planned for the Inquisitor's first appearance with Thomas Allman to go out before the title montage and setting up the villain as a significant threat, however this idea was dropped and the titles are still the first sequence with the villain appearing after.
- Jack Docherty as The Inquisitor
- Jake Abraham as Dave Lister (Alternate timeline)
- Tim Yeates as Kryten (Alternate timeline)
- James Cormack as Thomas Allman
- Trevor St. John Hacker as Thomas Allman (Alternate timeline)
- Carl Chase as Old Lister
- Duane Cox as Young Lister
- When Lister referred to facts about Rimmer to try and convince him that he knows him, he refers to his brothers as John, Howard and Frank (the viewer finds that out in Polymorph), that he was really mean with money (as mentioned in Marooned), that he once volunteered for the Samaritan switchboard and 4 people committed suicide (mentioned in The Last Day, although in this case, Lister wasn't counting the wrong number) and that the "BSc" in his official letters stand for Bronze Swimming certificate (first mentioned in his death video in Me²).