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.

Nikki and Jack assist DS Sally Kirchner in identifying teen-aged Alice Preston, who was murdered and her baby taken live from her womb. DNA identifies the father as married Simon Turner, who admits to a one night stand with Alice but claims he never saw her after giving her money for an abortion. Alice was a drug runner, sharing a flat with two other drug dealers, Mark Blakefield, who is also murdered, and Nuri Kavur, who turns out to be the informant for DI John Brooke of the drugs squad. Nuri believes his uncle, Turkish gangster Bekir Humadi, has slain the others after a consignment went missing and fears for his own life. Brooke arrests Humadi for the slayings, after finding evidence at the flat but Jack believes he is actually framing the Turk.

As Nikki tries to explain to Alice's father of her drug involvement Martin Carrisford, the witness to Alice's murder, is also slain. Humadi threatens Nuri to locate the missing drugs though he denies killing Alice. Nuri is shocked to find that Brooke and his wife have Alice's baby . Brooke assures Nuri he does not know where the drugs are but Nuri steals the baby, taking it to Humadi to use as bargaining power with Brooke for the drugs or their value. Having accidentally discovered the drugs Brooke goes to broker a deal with Humadi, sacrificing Nuri, who is killed. Brooke is prepared to arrest Humadi but Jack works out who really murdered Alice and Carrisford and why.