When your face is worshipped as a god and a giant computer has gone rogue, you know you’ve taken a wrong turn in time and space.
Short Synopsis
The Doctor lands on a jungle planet where two tribes are locked in an endless conflict — one primitive, one “advanced.” Turns out it’s all thanks to a malfunctioning computer with the Doctor’s own face, which he sort of… forgot about leaving behind last time. Oops.
Extended Storyline
The Fourth Doctor arrives on a mysterious jungle planet, where the Sevateem (think “stabby jungle warriors with trust issues”) are convinced he’s an evil spirit. Their belief system is based around a god called Xoanon, who — surprise! — turns out to be a giant computer the Doctor once “fixed” on a previous unseen adventure. Unfortunately, his repairs left behind an imprint of his mind, giving the computer a full-blown identity crisis. Imagine Siri having schizophrenia and you’re halfway there.
The Sevateem are constantly at war with the Tesh, a group of smug, robe-wearing technocrats who think they’re superior because they live indoors and can work light switches. Both tribes worship or fear Xoanon, who now speaks in multiple voices, sometimes including the Doctor’s, which is creepy enough to unsettle even Tom Baker.
Enter Leela, a warrior of the Sevateem who doesn’t have time for nonsense and believes the Doctor is both dangerous and worth following around. (She proves her worth by trying to stab first and ask questions never.) Through her, the Doctor navigates the Sevateem’s superstitions, the Tesh’s smugness, and the computer’s psychosis, eventually confronting Xoanon in a bizarre showdown where he literally has to argue with himself.
After a tense battle of wits, the Doctor manages to overwrite Xoanon’s corrupted programming, restoring the computer’s sanity. Both tribes are left with a chance to coexist, though probably after a few more centuries of mutual distrust and light stabbing. The Doctor then tries to sneak off quietly, but Leela simply storms into the TARDIS and refuses to leave. Thus begins one of the most hilariously mismatched Doctor–companion duos in the show’s history.