The team is shocked when Leo Dalton's wife and daughter are killed when a fancy sports car careens out of control and smashes into a café. The police are puzzled by the cause of the crash but believe the driver may have been involved in a identity theft ring when they find several several passports and ID cards in the vehicle. Meanwhile, Nikki must perform urgent autopsies on two bodies found floating in the river. When she finds fingerprint evidence linking one of the bodies to the car accident, it becomes apparent that the two cases are linked and the police may have been less than forthcoming about their investigation.

Unsatisfied with the progress of the case, Leo Dalton takes matters into his own hands trying to get in contact with an identity theft ring. The information he gathers assists the police and they work together. The death of one of the gang members, and a vital clue, lead police to identify the their leader, but in the end, the solution brings little solace to Leo.

The body of teenager Katie Bowman is found dumped in an open grave. DI Carter suspects Ryan Kelvin, boyfriend of Lizzie Kennedy, whose daughter Hannah was Katie's best friend. He argued with the deceased girl the day she died and has no alibi. Ryan is also Jack's half-brother, whom he has not seen since he was forced to testify against him in a court case some years earlier. To avoid a clash of interests Thomas brings in pathologist Helen Ferguson, suspending Jack. Jack however does his own sleuthing. showing Carter that Katie had been to a club where she met Christy Nash, a married doctor with whom she had sex. Nash's wife gives him a false alibi to protect their daughter but declares her intention to divorce him. Ryan is bailed and moves in with Jack, who now doubts his brother's innocence whilst Hannah is killed after confronting Dr Nash.

Things look bad for Ryan when Lizzie tells Carter that he rowed with Hannah a couple of hours before she died as a result of which he makes an unsuccessful suicide bid. Nikki is surprised at the lengths Jack will go to exonerate his brother until he tells her that was the assailant in the criminal case and Ryan took the blame to save his career. Jack pursues Christy, who admits to falling for Katie, unaware that she was a minor but some while afterwards Jack is the victim of a hit and run, which he survives. Ultimately the killer proves to be protecting a professional, rather than a personal, interest though Ryan, cleared of the murders, is not wholly innocent of another crime.