When a woman's mummified remains emerge from the water during a cave rescue operation, Dalziel and Pascoe embark upon a treacherous murder inquiry which rocks their world to its core.

Dalziel and Pascoe's investigation comes under increasing attack, despite their best efforts to search for clues. However, they battle harder than ever to uncover the truth about the mummified remains, which they believe are connected to the case of the Yorkshire chief constable's ex-wife, who vanished more than 20 years ago.

On Halloween, Kate Johnson is killed in her bedroom, the victim of a shotgun blast. Her husband Guy is the obvious suspect, having now disappeared. In an odd twist, the couple had been part of a television broadcast the previous Halloween where hypnotist Lee Knight demonstrated that people could be induced to do anything, including murder. The dead woman's daughter, Katherine Taylor, is convinced that the hypnotic suggestions of a year ago are what caused her father to kill her mother and that Knight is responsible. When she is found dead however, the case takes yet another turn. Meanwhile, Dalziel undergoes hypnotherapy to quit smoking.

As the body count continues to rise, Dalziel and Pascoe continue to focus their investigation on Lee Knight. Knight continues to maintain his innocence and says he's being set up by someone. The police uncover that most of the principals are involved in witchcraft of one sort or another. As the victims' bodies are being dismembered, they believe the killer is set to perform some type of ritual. Pascoe believes Knight is innocent and the true killer is someone who is well-known to Andy.

A sunburned Det. Supt Andy Dalziel returns from his holiday in Australia and finds himself immediately investigating a murder. The dead man is Declan Roach, a researcher at the local university who was found in a university laboratory clean room. The autopsy confirms that he died from nitrogen intoxication but it is not clear at first if it was accidental or not. Roach was working under the direction of Professor Fran Cunningham, who in turn has a major contract with Aphrodite, a major cosmetics firm. She is working on a formula for a rejuvenation cream that will be nothing less than a fountain of youth and there is obviously a great deal of money at stake. Andy meanwhile is thinking of packing it in and emigrating to Australia.