Leo Dalton investigates the death of a young boy whose body is found in the river. He was badly abused and his hands and feet were severed. The child is found to have been HIV positive and the pathologists determine that he may have been the victim of a ritual killing., perhaps as part of an exorcism that went too far. When the skeletal remains of another child are found, Leo believes the police have focused their investigation on the wrong man. Nikki Alexander investigates the apparent suicide of Father Anthony Reid who appears to have jumped from his apartment window on the grounds of a well-known Catholic school. He had colon cancer but those who knew him question that he would take his own life. Harry Cunningham looks into the case of Austin Chambers who is found floating in his swimming pool with an obvious ligature mark on his throat.

When a second person, Vincent Fricks, is found dead with ligature marks around his neck, Nikki and Harry not only find a connection between the two dead men but also with the school where Father Reid committed suicide. They also find another common link between the three. Leo Dalton continues his investigation into a local church that combines Christian with African beliefs and customs. He manages to find physical evidence linking one of the dead boys to the church.

Forensic evidence given by Nikki contributes to the release on appeal of disturbed ex-soldier David Bennetto, charged with murdering two gay boys, one of whom he had sex with. DI Rachel Klein is not convinced of David's innocence , especially when a rent boy calling himself Byron Lee is shot dead and David's car is caught on CCTV near the murder scene. The fact that Nikki is dating Bennetto's solicitor Greg Walker makes her partial in the inspector's eyes and she is removed from the case. On the night that yet another gay youngster Charlie Masham is also shot Greg, on a date with Nikki, gets a frantic phone call from Bennetto and they go to his flat where he points a gun at them after he discovers Nikki has found his kitbag containing the murder weapons

The police surround the flat but David hands the gun over to Greg, explaining that it was his father's gun, which he had found and wanted to get rid of. Nikki is verbally abused by Charlie's father and DI Klein wants her suspended but Clarissa and Jack discover that the gun found by David did not kill Charlie and nor could he have killed Byron Lee. The pathologists work out that the real serial killer had an alarming insight into David Bennetto's background and their motive was not sexual but obsessed with having power over others. Circumstances also end Nikki's involvement with Greg Walker.