Published 1999; written by Christopher Bulis, featuring the First Doctor, Susan, Ian and Barbara.
When the TARDIS materialises on top of a skyscraper in a seemingly abandoned city, the Doctor, Susan, Ian and Barbara are separated in a meteor strike, with Barbara lost in the city sewers while Susan is taken to a hospital and the Doctor and Ian to the equivalent of a refugee camp. Learning that the planet's moon is in a descending orbit and set to crash in a month, the Doctor and his companions volunteer to assist in the effort to construct a spaceship that will allow the last surviving members of the population to evacuate to another planet, but soon realise that others on this planet have their own agenda.
Tropes
- A.I. Is a Crapshoot: Monitor was created to serve the people of Arkhaven as a direct assistant to the Mayor and the government as a whole. It is ultimately revealed that Monitor has been manipulating the situation for years, exploiting various legal loopholes to expand his remit to allow him to essentially plant android duplicates among the human population.
- Flaming Meteor:The moon of the planet Sarath has been set into a descending orbit after it is struck by a meteor, with serious geological implications even before it strikes the planet. By the time the TARDIS arrives, there is just over a month before the moon will hit and destroy all life on Sarath.
- Homeworld Evacuation: Essentially applies; Sarath is all-but-explicitly identified as a human colony that lost all records of its origin and had to start its space program from scratch. As a result, by the time the moon starts to fall, they can only build a rocket capable of evacuating the inhabitants of the city of Arkhaven, which all evidence suggests is the last surviving city on the planet, and even their research is not able to create an engine large enough to power the ship in question.
- Ignorant of Their Own Ignorance: Even once the crisis is over, none of the TARDIS crew are aware that Barbara was briefly brainwashed by the Taklarians.
- Kill and Replace: Essentially Monitor utilises this; when people in terminal conditions are put into stasis for treatment, Monitor is able to replace them with specially-designed android duplicates, able to justify the loophole on the grounds that the people aren't actually alive when they're in stasis so it doesn't qualify as killing them.
- Mr. Exposition: The Doctor and Ian acknowledge that they know nothing of the existing social order, and question other people in the camp where they have been sent to establish what they are dealing with.
- Nice Job Fixing It, Villain: While the Taklarians intended to take the Ship for themselves, their efforts allow Mayor Draad to destroy the Ship while somewhat justifying having to kill so many innocent people, and their efforts to brainwash Barbara as an agent provoked her to cause a distraction at a key moment.
- Noah's Story Arc: The people of Arkhaven are attempting to construct a vast spaceship to take its population to the neighbouring planet Mirath before Sarath's moon crashes into the planet and destroys it. In the end, construction issues and internal conflicts mean that only just over a thousand survivors can make it to Mirath out of a population of over eighty thousand.
- Race Against the Clock: When the TARDIS arrives on Sarath, the Doctor soon establishes that he has just over a month to replace the TARDIS key and help the natives get their ship in working order before the decaying moon crashes into Sarath; the situation escalates when the moon fractures in advance of the predicted schedule, leaving them with eight hours to get everything together and off the planet.
- Robot Me: Susan's robot double plays a key role in the final clash; various other parties have also been replaced by robots, but Susan is the only one still alive.
- Spanner in the Works: Susan in particular serves as this to Monitor's plan; every other person Monitor replaced with a robot subsequently died, but Susan survived due to her Time Lord physiology.
- Tomato in the Mirror: Throughout the novel, Susan is shown to be in two places at once, either being treated in the hospital or escaping being burnt to death in a rubbish tip. In the final clash, it's revealed that the Susan in the hospital is a robot duplicate created by Monitor, and various other citizens of Arkhaven have also been replaced by robots.
