C'rizz explains that although the TARDIS is gorgeous and he's enjoying the Eighth Doctor's botanical gardens, his culture just has a very different definition of beauty — it needs context. He'd like to see a pre-industrial planet, so the Eighth Doctor takes him to a pristine one, where they immediately encounter a creepy little girl singing "scaredy cat!" over and over. The Doctor decides to investigate as to how a ghostly girl can know an Earth children's rhyme.
They find a crew of scientists from a nearby human colony, who try to stick to their Alien Non-Interference Clause but mostly just want to meddle without anyone noticing. While Charley gets to know them a bit better, the Doctor finds the creepy little girl on a stone altar in the middle of the woods, seemingly comatose. He tries to reach into her mind and make "Contact!" with her, but only succeeds in accidentally subjecting himself to Mind Rape.
Eight decides to take a more hands-on approach and vworps himself and C'rizz four billion years back into the past, to the very beginning of the planet. They find an interplanetary colony base, beset by a plague — which was spread on the planet by passing scientists who just wanted to experiment a bit. The colonists are waiting for a med team to arrive. One of the colonists, the creepy little girl, accepts a jelly baby from Eight and remains blissfully unaware of what's going on. The Doctor knows that he could fix them all up easily with the TARDIS medbay, but also knows that he can't interfere and shred the web of time. C'rizz decides to take matters into his own hands and gives the colony medicine anyway. It doesn't help, since the dosage was never enough. The little girl will survive the plague thanks to her inherent immunity and, after stumbling around the corpses for a while all alone, will end up starving to death and getting absorbed into the morphic field of the newborn planet. Eight explains that meddling with newborn planets it something no Time Lord should ever do, and that the girl, and her memories of him and C'rizz, are now part of the planet's evolutionary schematics.
Meanwhile, Charley has been irritating the scientists so much with her questions that they've locked her up Alone with the Psycho: a war criminal named Flood, who's being experimented on by the team. Their lead scientist, who lost loved ones to murder before, wants to know what makes evil people tick. Unfortunately for the team, the experiments acidentally connect the madman's mind to the planet's morphic field, making him into a Reality Warper who can feel the pain of all the colonists long ago. Flood starts using the team as People Puppets and gleefully making the planet's natives kill each other. He also takes C'rizz hostage. C'rizz calmly explains that he's a killer who slayed his own beloved once, and that he's dangerous. Flood sees right through him and knows that C'rizz has killed quite a lot more people than just his beloved, but that he's really not all that evil or dangerous. Since the plague is still present on the planet in trace amounts even after four billion years, Flood plans to strengthen those trace amounts and eventually spread it all the way to his home planet in revenge. C'rizz is forced to shoot the Doctor, but is able to resist enough to change the setting on his blaster to "harm" instead of "kill". After the little girl's spirit defeats Flood quite thoroughly, the Doctor reassures C'rizz and tells him he doesn't believe C'rizz is inherently a killer.
Tropes:
- Alone with the Psycho
- And I Must Scream: Professor Arken ends up being frozen in place, unable to move his body, unable to speak, with just a muffled mumble, and, more than likely, lobotomized afterwards.
- Black-and-Grey Morality: Mr. Flood is being experimented upon, but he's a convicted serial killer.
- Call-Back: C'rizz is still trying to form a new personality, and is trying to find his identity either as a killer or as a regular person.
- C'rizz mentions having killed his lover. And his adaptive personality comes back into play.
- The Doctor mentions Block Transfer Computation, mention, amongst other places, in Logopolis.
- Continuity Nod: The Doctor harkens back to the origin of the Daleks and the creation of the Cybermen, both he were present for.
- Creepy Child: Galayana.
- Faux Affably Evil: Mr. Flood
- Fisher King: Mr. Flood and the planet.
- Frazetta Man
- Gaia's Vengeance
- Gone Horribly Right
- Half-Human Hybrid: Mr. Flood thinks C'rizz is one of these.
- Last-Name Basis: Mr. Flood is almost exclusively referred to as Mr. Flood.
- Mind Control
- More Dakka: Suggested as a plan how to get to Flood.
- Not That Kind of Doctor: Played for drama. The Doctor arrives at a settlement caught in a batch of The Plague.
- The Plague
- Powered By A Dying Race
- Psychic Powers: Whilst the Doctor denies he's outright got Telepathy, he does have mental powers and can link up with people.
- Mr. Flood
- Sentry Gun
- Shout-Out: To sir Walter Scott.
- Tested on Humans
- Title Drop
- What the Hell, Hero?: C'rizz towards the Doctor, in regards to The Plague.
- You Can't Fight Fate