In Yorkshire, 1978, a horrific crime unfolds as a mother, father, and their three-year-old son are viciously stabbed to death in their sleep. The family, once seen as exemplary, leaves the nation in shock due to the lack of any apparent motive. The brutal nature of the murders ignites public outrage, with many in Britain calling for the reinstatement of the death penalty to ensure justice is served. Astonishingly, the perpetrator, caught in the act of attempting to remove the father’s body from the scene, successfully conceals the young child’s body in a location that eludes investigators, police, and even search dogs. For months, the country is consumed by discussions about the “Kid Killer.” Yet, the most shocking revelation is not the cold-blooded murder of his family but the identity of the killer himself: their twelve-year-old son, William.