When a young woman's body is discovered on a popular jogging trail in Birmingham, Detective Inspector Bernard Watts and his team are plunged into a disturbing murder investigation. Not only has the woman been violently stabbed - her head is missing. When a close examination of the crime scene results in a shocking discovery linking the present murder to a past crime, criminologist Will Traynor is brought in to assist the police. Aware of Traynor's troubled past, Watts is sceptical that he will bring anything useful to the investigation. He's about to be proved very wrong . . .