A long-buried body is unearthed in Flagford, England - on the property of grouchy John Grimble - and Chief Inspector Wexford and his team investigate. The detectives learn that Grimble dug a trench eleven years before to prepare the property for additional homes. Denied permission to build the houses an incensed Grimble filled in the trench - which by then apparently contained a dead body. Soon afterwards another set of human remains is found on Grimble's property, in his old abandoned home. This body appears to have died about eight years before.
Much of the story involves the detectives trying to figure out the identity of the dead people, and then discovering who killed them. To do this they need to question all the people living around the area at the relevant times. This includes old Grimble himself, the writer Owen Tredown - an author with one successful and several mediocre books, Tredown's wife and ex-wife - two controlling women both of whom live with the author, and elderly Irene McNeil - a snobby bigot who previously resided across from the Grimble house. These characters are well wrought and believable.
A side story concerns the population of Somalis in the region, and their tradition of female circumcision. Wexford - spurred on by his daughter and child health advocates - tries to prevent a Somali family from performing this horrific procedure (which is illegal in England) on their little girl. This is a serious and worthy issue but it felt like an add-on that didn't really fit with the mystery story at the heart of the book.
Much of the book consists of detectives searching through missing persons files and questioning and re-questioning persons of interest. Little by little they discover information that leads to the resolution of the case. The story's climax seemed somewhat unlikely and wasn't totally satisfying. Many of Rendell's other books are better; this is just an okay mystery.