The Fifth Doctor and Nyssa arrive on the planet Veln, and Nyssa is promptly beaten up, arrested for murder, and interrogated.
The story unfolds entirely in Anachronic Order. It's revealed that the planet's atmosphere was completely ruined, four generations ago, by a race called the Koteem. The Veln are all grotesquely mutated by the resulting pollution, and see the Koteem as their mortal enemies, now shrouded in fearful legend. Only the Koteem, and those rich Velm who can afford reconstructive surgery, are able to look like The Beautiful Elite.
This got the Fifth Doctor and Nyssa into trouble as soon as they landed on the planet, following an unexpected crash in space (a few centuries earlier for the planet, a few minutes earlier for Team TARDIS) with an unexpected spaceship. The Doctor is really quite confused about the whole thing, and especially about being mistaken for an interstellar agent at first and for a Koteem soon afterwards. Mostly because he knows that Koteem are all (a) spider-shaped and (b) extinct. He quickly shuts up once he realises that the whole "extinct" thing hasn't happened yet.
As it turns out, the ship that the TARDIS crashed into was a Koteem waste disposal mission, and the crash caused the pollution to spread into the planet's atmosphere and mutate its inhabitants. The Koteem, wracked with guilt over having accidentally committed slow-burn genocide, have decided to commit a species-wide Heroic Sacrifice. They plan to secretly merge their bodies with cooperative members of the Veln elite, granting them their own Koteem immune system and allowing the Veln to live on beyond this generation, at the expense of the entire Koteem population. When one of their experiments went wrong, the poor victim ran into Nyssa and killed herself out of fear, which is what got Nyssa arrested in the first place.
Once all the confusion is sorted out, the Doctor eventually just leaves, blissfully unaware of how the pollution was spilled and never realising that he's accidentally committed genocide.
Tropes:
- After the End: The story takes place on a planet which has gone through an apocalyptic event, diving the people in two classes.
- Alien Sky: It is green. For a reason.
- Anachronic Order: The story is told in snippets, flashing back and forth, adding on previous scenes, or introducing upcoming ones akin to 21 Grams.
- The Beautiful Elite: To the degree that the Fifth Doctor is immediately thought to be one of them, just because of how "fair" he looks.
- Bizarre Alien Biology: The Koteem get transplanted into the Veln in order to keep a few of them alive.
- Broken Record: Beau-beau-beau-beau-beau...tiful.
- Death Equals Redemption: The Koteem believe this, as they sacrifice themselves to keep the Veln alive.
- Holographic Disguise: Of a mountainside with a Force Field.
- Humanoid Aliens: The Veln are practically identical in appearance and function to Gallifreyans. According to a Veln scientist.
- Ironic Echo: "As for making a difference? I don't think we really influenced anything at all."
- Mike Nelson, Destroyer of Worlds: Poor, poor Five inadvertently caused the Apocalypse How that formed the setting of the story by flying through an anomaly with his TARDIS, lands on the planet, and never finds out that he himself caused all the suffering he encounters.
- No Antagonist: Nobody really bears any ill will towards the others. The world is just in a horrible state.
- Nonhuman Humanoid Hybrid: The Veln that are part Koteem due to organ transplants.
- Obviously Evil: Played With. The Doctor wishes bad guys would have satanic beards.
- "Shaggy Dog" Story: In the end the Doctor and Nyssa are just allowed to leave, and they never find out that they caused the Apocalypse How.
- They Should Have Sent A Poet: The description of how the pollution spread is really quite gorgeous.
- Unusually Uninteresting Sight: Both the Doctor and Nyssa find it odd that the fact they're aliens isn't remarked upon.
