With Andy Dalziel at home recuperating from his heart attack, DI Peter Pascoe finds himself in charge of investigating a suspicious death when Nurse Maggie Hopcraft finds Harriet Vanstone dead in her seaweed bath. Vanstone was staying at a health clinic undergoing a variety of spa-like treatments and the doctor who had attended her the day before, Allison Laurie, is prepared to certify the cause of death as a heart attack. Peter isn't so sure but certainly develops an interest in the very attractive doctor. Andy meanwhile is bored to tears sitting at home and, unable to officially return to work, decides to check himself into the clinic to see what he can find out. A second death convinces both Peter and Andy that there is definitely something going on.