Roots: There are references to Back to the Future, Justin Bieber, Jules Verne, H. G. Wells, the Pied Piper of Hamelin, and Minis. The Clockwork Owl in Archangel’s collection may be a nod to Clash of the Titans.
Continuity: The Squall are winged, flying (or at least gliding) bipeds with smooth, hairless, grey flesh, an angular body, an upturned snout, red eyes, needle-sharp teeth and talons. They feed on psychic energy and can also manipulate it, creating psychic dampening fields to prevent people from noticing them. They are parasites that live outside of space and time and are constantly trying to find a way in to feed. They spread like a plague. They are hive creatures with a hive mind and become more intelligent the more of the hive is together. They are essentially an individual creature with any number of bodies or drones. They begin an invasion by sending a number of scouts to a world. Any more than three together, and they are able to communicate with other beings.
The AIs resemble tall hairless humans with pale skin. They have rubber flesh.
The Doctor is planning on taking Amy and Rory to the Rambalian Cluster when the TARDIS is drawn off course. He carries a small pair of binoculars in his jacket pocket. He uses the psychic paper to pose as someone from the city conservation board. He has heard of the Squall. He drinks tea with Archangel. He cobbles together an amplifier to boost the effect of the sonic screwdriver on the Squall.
Amy once visited the British Museum as a child. She hates rats. Rory visited the British Museum as a child and saw a mummy.
Professor Archibald Angelchrist has encountered strange tentacled aliens that climbed out of the Thames, an extraterrestrial virus that drove people murderously insane, and an ancient entity awoken from its tomb beneath Edinburgh.
Links: Amy mentions the Byzantium (The Time of Angels/Flesh and Stone). She also refers to drilling disturbing things below the Earth (The Hungry Earth/Cold Blood). The Doctor mentions Bessie. He refers to flying a double-decker bus through a hole in space and time (Planet of the Dead) and the TARDIS imploding and destroying the universe ([tv]The Pandorica Opens[tv]/The Big Bang). Rory recalls aliens made of wool (The Glamour Chase), vampire creatures from the stars (Vampires of Venice), and exploding nuclear bombs (Nuclear Time).
Location: London, 13th to 17th and 23rd October 1910 and 10th June 2789.
Future History: The android AIs have been on the market for two or three months in June 2789. They are manufactured in the Villiers Artificial Life laboratory in Battersea. Artificial people are granted their liberty one or two centuries after 2789. St Paul’s Cathedral, Buckingham Palace and the Tower of London are all still standing in 2789. The city contains glass domes containing jungles, which act as oxygen factories.
Unrecorded Adventures: The Doctor is dealing with a Sarkovian warlord when he drops Arven off at Professor Angelchrist’s house.
The Bottom Line: A cracking time travel/horror story, with some great characters (notably Arven and Angelchrist) and memorable monsters. Mann has a great grasp on the regulars and ties the paradoxical nature of the plot up in satisfying fashion.