Cracker

Following the murder of a prostitute, the police call in Fitz to investigate. An arrest is made and the main suspect, David Harvey (Mark Lambert), 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.

With DS Beck now back on the force, DS Penhaligon has no choice but to work with him despite her conviction that he raped her. Fitz's life is placed in further turmoil with the death of his mother, and the police question Harvey's family in an attempt to stop more killings.

As DS Jimmy Beck and DS Penhaligon face up to the dramatic events of the past, Fitz discovers the terrible truth behind both the murders and the rape.

DS Penhaligon attends DS Beck's funeral, to make sure he is really dead and buried. Homeless factory worker Bill Nash is given refuge by his foreman Stuart Grady, but the landlady gets into an argument with Bill, and he murders her. After being interviewed by the police, Bill and Grady go on the run which leads them to Nash's adoptive family's home and yet another death.

Fitz discovers Bill was returned to foster care by the Nash family leaving permanent scars. Meanwhile the police make the connection between Bill and Grady who is in the hospital after getting burnt. With Grady captured, Fitz realizes where Bill will go next but can he make it in time to save Diane Nash?

Fitz takes some teaching work at the University where he begins receiving love letters. Janice, a lab technician, is the writer of the letters and in her depression over her lack of attention from her family, begins murdering make students she has lured into her room. The police want to take Fitz off the case as they understand that the murderer is writing to, and killing, for him.

Fitz asks DCI Wise to replace him with Irene Jackson, as the killer may stop killing without his individual attention. Janice changes tack and lures Fitz's son to her flat, but when the police catch her, she is alone. With Mark Fitzgerald's life in jeopardy, Fitz must use all his powers of interrogation in finding his son before it's too late.