Wisting - hero of the hit BBC4 detective show - must prevent a murder who escaped justice 20 years ago striking again.
In 1999, seventeen-year-old Tone Vaterland was killed on her way home from work. Desperate for a conviction the police deemed the investigation an open-and-shut case and sent her spurned boyfriend, Danny Momrak, down for murder.
But twenty years later William Wisting receives a puzzling letter. It suggests the wrong man was convicted for Tone's death and the real murderer is still out there.
Wisting is quickly thrown into a terrifying race against time where he must find the sender, decipher this mysterious letter and catch the real killer before they strike again.
