Following the suicide of colleague Lizzie Fraser, who he believes was scapegoated by police for a wrong decision, Leo comes to work in an angry, bitter mood. DI Connie James brings Leo, Harry and Nikki in following the brutal slaying of ex-SAS soldier Mick Francis, his daughter Jessie, and her young son Luke at their farm shop during a robbery. Harry establishes a good rapport with the pregnant Connie but then Superintendent Byrne links the murders to that of Lizzie's sister Mary twelve years earlier and to several other unsolved murders in the intervening years. Byrne believes the killer is a drug-addicted woman known as the Wraith, working with a male accomplice. However unknown to him a hooded white boy who was at the shop would seem to fit the bill.

Leo attempts to help Mark Benson,whose wife Shona was imprisoned for killing their baby and begins to spot discrepancies in the expert witnesses at the trial. Petra Smith is abducted and imprisoned in a remote farm building at the same time as two women's corpses are discovered in a basement. The officer in charge, Chrissie Reid, once has an affair with Jack until he accused her of corruption in order to get an arrest. The two women have been injected with a toxic substance and Chrissie and Nikki visit the factory that makes it. The suspicious actions of scientist Lucas Ballinger cause them to follow him to the hide-out where a man called Hearns has imprisoned Petra and is about to inject her though Lucas is scared as he had not realised that anybody would die. Hearns kills him and sets fire to the building and Chrissie pursues him, leaving Nikki inside the burning building.