Forensic pathologist Dr. Sam Ryan returns to Cambridge to take up a teaching assignment and to work for the police as required. In her first case, she has to deal with the death of a six year old girl find floating in a nearby river. The autopsy reveals that the child has suffered previous abuse, including cigarette burns and several broken ribs. Sam receives information from a prison inmate that implicates someone in a previous death and Sam suggests a radical step. In her personal life, Sam has to deal with her elderly mother who is showing signs of dementia and her sister Wyn with whom she has a strained relationship.

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.

Sam investigates the death of a gay man while in police custody. He had been arrested while drunk and was sharing a cell with another drunk, in for the night. The victim died from a blow to the head and was badly beaten post-mortem. DS Farmer is concerned that the assault may have been the work of some of her officers. Sam also meets up with Liam Slattery an old friend she has not seen for 20 years. Sam's sister however is convinced Liam was responsible for the death of their father years before.