The corpse of a beautiful woman, clad in only a bathing suit, is found strangled to death on a popular Sussex beach. When she is finally identified, it turns out she was a top profiler for the National Crime Faculty, who was working on the case of a serial killer. And though she was a Bath resident, the authorities don't want Detective Superintendent Peter Diamond to investigate the murder. How strange. What could they be trying to hide?

When van driver Bob Naylor, who likes to write jingles, is prodded by his teenage daughter into joining the Chichester Writers’ Circle, he scarcely expects to find that, among the anticipated set of literary snobs, he will be rubbing elbows with one—or more—potential victims of murder by arson. The members come from all walks of life and practice all forms of writing, from torrid romances to household hints, but there seems to be nothing to cause a serial killer to choose his victims from among them. But as the killer strikes again and again, Bob becomes a suspect. In order to free himself from suspicion and save himself from going up in flames, he will have to cooperate with formidable CID Chief Inspector Henrietta Mallin—Inspector Peter Diamond’s opposite number from The House Sitter. It begins to appear that amongst the potential victims in this circle are one or more murderers.

Gemma loathes her sleazy boss; Jo is her confidante. On a double date with Rick and Jake, they discuss forming a mutual murder society, in jest of course. The next day, Jo, walking on Selsey Beach, discovers the corpse of a drowned woman, a stranger. But one of the men in the lineup at the police station is Gemma’s date Jake, who Jo rather fancies. Then Gemma and Jo discover the corpse of Fiona, Gemma’s annoying colleague from work. And Gemma’s boss is missing. When an older woman whom Rick was involved with is drowned in her pool, the police begin to close in. Can this outbreak of deaths by drowning be coincidental? Or has the joke gone too far?