Nocturne tells the story of Jonah Lynn, an ex-soldier turned homicide detective who, tired of working the tough streets of Philadelphia, moves to a small town in Western Pennsylvania for a quiet life. But, as the town and his family come under attack from the diabolically cunning serial killer Jurek Walter, Jonah must protect all that he holds dear. When the desperate search for Jurek's last missing victim forces Jonah to send his adopted daughter, FBI Agent Saga Bauer, up against Jurek, how far will Jonah go?