When the body of teenager Julie Ann Collins is found in the underground car park of a Hackney housing estate, probationer WPC Jane Tennison becomes immersed in her first murder investigation.

Tennison hunts down a lead in the Julie-Ann Collins case. Meanwhile Clifford Bentley's puts his family's criminal interests in jeopardy.

As new evidence emerges, Julie Ann Collins' family are forced to acknowledge the brutal truth about her final days.

Following the arrest of the mysterious 'Oz', the investigation takes an unexpected twist. The Bentleys' plans are nearly blown out of the water by a visit from the police.

Bradfield sees a chance to get revenge on Clifford and diverts the team to carry out surveillance on the Bentleys – and when Tennison learns of the operation, she's forced to make a split-second decision as to what is most important, her career or her family? As Bradfield uncovers more about the heist, he faces disapproval from his colleagues as he becomes determined to catch them in the act.

In the aftermath of the bank vault explosion, the police operation descends into pandemonium and panic. As Tennison arrives at the scene, she is met with devastating news.