Freakangels is set in a time after London has been flooded. A group, called the Freakangels, live in Whitechapel and their life encounters a dramatic bump when a girl called Alice arrives one day, bearing a shotgun and a grievance against one of their number. Ellis' synopsis of the plot involves characters "living in a post-flood London that they might possibly have had something to do with."
As the story progresses, eleven of the FreakAngels, who all possess telepathic abilities and some of whom possess other skills, are introduced and their role in the community is expanded. Mostly together, they have created a small (roughly 300 people) civilization, complete with fresh water, watch towers, markets, home-grown vegetables and a medical clinic. However, their society is threatened externally from refugee attacks and internally from personal conflicts and crime.