The collapse of Owen Pierce's trial has left the case wide open and there's still a killer on the loose, but Banks remains determined to build a watertight legal case against his prime suspect. As the investigation continues, Morton and Jackman uncover promising new leads focusing on Ellie's ex-boyfriend Tyler, but just as they seem to be getting close to the truth, another schoolgirl is murdered, putting Pierce in the spotlight once again.

Frustrated that a number of cases have been knocked back by the Crown Prosecution Service, Banks and the team are called on to investigate the murder of teenager Ellie Clayton, daughter of a high-profile internet entrepreneur. The victim's background, together with the suggestion she may have been raped, means the incident is soon the subject of much media speculation, and strong evidence implicates a theatre director who ran a drama workshop the girl attended on the night she died. The detective believes he has found his man, but Morton fears her colleague isn't seeing the bigger picture.

With Pamela Jefferies in a coma following her vicious attack, Banks becomes more determined to find Rothwell's killer. Convinced a vital clue is staring him in the face, he resolves to learn more about Keith Rothwell and, against orders, questions MP Martin Fleming, putting him on a collision course with rival DCI Burgess. Meanwhile, the return of Tom Rothwell to the UK presents Helen with another suspect and an opportunity to put pressure on his family.

A professional hitman bursts into the luxurious family home of accountant Keith Rothwell and shoots him in cold blood. Banks is instantly struck by the strange reactions of the victim's family and evidence comes to light that Rothwell has been living a secret double life. Now investigating the murder of a victim with two identities, Banks and Morton discover a possible link to a major money-laundering operation and are plunged into a high-profile fraud investigation with political ramifications.

Banks visits his childhood home to break the news of Roy's death, and his parents plead with him to find out what happened. Defying Morton, he returns to the station in an attempt to lead the investigation into the murders of his brother and Jennifer Lewis, and both officers are convinced the key to cracking the cases lies with a woman being treated at a clinic.

DCI Banks receives a disturbing phone message from his estranged brother Roy and heads to Harrogate to find him. Meanwhile at a murder scene, the team is introduced to new recruit Helen Morton, who quickly alienates her colleagues with her tactless style. She then makes matters worse when she finds evidence linking Banks to the victim's body and speculates he could be a suspect. Unaware everyone is searching for him, Banks begins to delve into Roy's life and soon uncovers questionable business transactions and associates.