When Mark James' decomposing body is found in an abandoned building, there is every indication that he was part of some occult ritual. An upside down cross was carved on his chest, his wrists were bound with ivy and he was strangled. All evidence points to his friend Sebastian Bird, a rich idler who allowed James to live in his house but who had also developed a expert knowledge of the occult before being sent down from Cambridge for having had an affair with a professor's wife. Sam Ryan's testy relationship with the police continues as she is having difficulty establishing a forensic link in the case and also for publicly criticizing the well-liked Police Surgeon, Dr. Richard Owen, for attending the crime scene without the proper protective clothing. Sam also has to deal with her rebellious nephew Ricky, who is constantly fighting with his mother and announces that he has left home to move in with her.

Sam continues her investigation into Mark James' murder. When another of Sebatian Bird's one-time friends is killed the police are ever more convinced of his guilt and grow increasingly frustrated at Sam's inability to provide them the evidence that they are sure is there. The solution lies in an old case and someone's desperate need for revenge.

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.