An evil force is looming across the dark, thick-aired streets of industrial revolution London when a group of heroes dubbed Unicorn are accidentally reawakened in the bodies of teenagers instead of adult hosts they’ve embodied in the past.

Convicted murderer Clyde Thompson receives the death penalty for shooting two men in Texas in 1928. When the governor spares his life, Thompson gains a reputation as the meanest man in the state while working hard labor in prison.