The year is 2145 - setting, London. There aren't that many people left now, but everything is different - floods and harsh temperatures occur frequently, and no one can be considered safe.
Dr. Robert Karans is a biologist and is part of a modern scientific team sent around the country to explore the evolutionary aspects of this new world. It seems that humans and plants alike have started devolving faster, most likely because of the extreme climates that they are not suitable to adapt to. Karans and his team travel to a lagoon that boils over to inspect flowers and such, but everyone on the team gets bad dreams. This scares them, and the mission falls apart.
Beatrice and Dr. Bodkin are two people that Dr. Karans begins associating with when the rest of his team runs away. These three decide to live together by the lagoon to live an isolated existence. A man named Strangman arrives, and he ruins all that the group stands for. Bringing with him other survivors of this apocalyptic scenario, he influences them to devolve with the rest of the world. He also leads an effort to drain the swamp where they are staying, and, to everyone's surprise, they find a city under all of the water - that city is London.
Dr. Bodkin does not want to give in to the ways of this Stangman and defies all that he stands for. Beatrice and Dr. Karans have given in to him, but Bodkin continues fighting until Stangman kills him in "revenge". After this, Dr. Karans also grows weary of Strangman's rule.
Strangman imprisons Karans and has Beatrice under what seems to be hypnotic control. Karans tries to save Beatrice and free himself from the odd rituals that Strangman is imposing on him but does not entirely succeed. He saves himself, but not Beatrice. Karans is weakened by the ordeal, both physically and mentally, and decides to run away. In his journeys, he meets Hardman, another lonely traveler like him.
