1950s Kenya, during the Mau Mau, a foursome of upper class British, during a perimeter check of their (appropriated) farmhouse find a small unusual native. Except he's double jointed, and has two opposable thumbs.
The Doctor finds himself in the middle of things, just before a greater threat than angry natives and he's forced to deal with Dr Elizabeth Klein a familiar face from his past, as death comes carried on a thousand tiny wings.
Part of a trilogy that continues in Survival of the Fittest and concludes in The Architects of History.
- Absolute Xenophobe: Mrs. O'Donnell wants to kill someone (who they suspect to be diseased and dying) merely because they're "Not British".
- All Germans Are Nazis: Said word for word by Dr. Klein.
- Dr. Klein: All Germans Are Nazis, all Nazis are Gestapo, and all Gestapo are monsters.
- Alternate Timeline: This Elizabeth Klein is from a future timeline in which the Nazis took over Europe.
- Broken Bridge: The fence surrounding the farmhouse has been barricaded with burning cars and a tree trunk, suspected to have been done by the Mau mau..
- Call-Back: Elizabeth refers to "Ms. McShane."
- The Doctor mentions he's got "happy memories" of driving and big green landrovers.
- The Doctor references having met Neo-Nazi Hans de Flores.
- Contrived Coincidence: The Doctor says the universe works this way, which is why he randomly stumbles upon people like Dr. Klein repeatedly.
- Darkest Africa
- Death of a Thousand Cuts: The Cheylis can scratch and peck a person to death.
- Feathered Fiend: The Cheylis, a bird race.
- Hive Mind: The Cheylis.
- "I Know You're in There Somewhere" Fight: The Doctor and Dr. Klein try this on Abraham.
- Last-Name Basis: The Doctor refers to Dr. Elizabeth Klein as just "Klein".
- Magic Antidote: The Cheylis, conveniently, have created a universal cure for all of their poisons.
- Mighty Whitey: Mrs O'Donnell consideres the white people this to the primitive "childlike" native Mau Maus.
- The Mole: Joshua.
- Not That Kind of Doctor: Dr. Klein used to not be that kind of doctor but has brushed up on her medical science since the last time the Doctor saw her.
- The Plague: In Dr. Klein's timeline Northern Africa was struck by one.
- Doubles as a Synthetic Plague.
- Plague Master: The Cheylis are adapt at biological warfare.
- Pragmatic Villainy: Klein states that she has no interest in utilising the plague as a weapon for her own agenda because it would be too uncontrollable.
- Properly Paranoid: Mrs O'Donnell says they should leave Joshua to his fate. Turns out he was a Mau Mau spy all along.
- Set Right What Once Went Wrong: In Dr. Klein's timeline the Nazis bombed northern Africa which kickstarted a plague so heinous that they stayed out of Africa for decades, though she still wants to...
- Make Wrong What Once Went Right: Dr. Klein still has this motivation in regards to the Nazi Empire.
- Shout-Out: The Doctor mentions having had arguments with Frank L. Baum over Monkeys with wings no longer being monkeys.
- Slave Race: Whatever "Abraham"'s species is, they function as a form of manipulated mules by the Cheylis.
- The Swarm: The Cheylis are roughly the size of a humming bird and flock people to kill them.
- The Trains Run on Time: Referred to by the Doctor as the "welcome" alternative for freedom.
- Translation by Volume: Mockingly referred to by Dr. Klein.
- Translator Microbes: The Doctor mentions if it's a language, the TARDIS can translate it. ... Except for Esperanto.