Robbie Coltrane stars as Fitz, a brilliant but flawed, wise-cracking criminal psychologist who looks behind the evidence of a murder to discover what lies within the criminal mind. Following the murder of a prostitute, the police call in Fitz to investigate. An arrest is made and the main suspect, David Harvey, is brought in for interrogation. However, when an identical murder takes place, the team have to consider whether they have the wrong man or a copy-cat killing. As D.S Jimmy Beck and D.S Penhaligon face up to the dramatic events of the past, Fitz discovers the terrible truth behind both the murders and the rape.