Summary: Three subtly related murders are solved by painstaking accumulation of evidence and careful inference. The first initially appears to be a random act of delinquency: Someone drops a mass of concrete from an overpass onto a moving car on the road below. The second victim is a young single mother, still living with her parents; she is hit in the head with a brick or a piece of masonry while returning from a night out with her friends, and is found to have recently received a surprisingly large amount of money. After the second murder is discovered, one of the victim's friends disappears; her body is found only after a week.

The success of the investigation depends on the ability of the police to understand the motives and compulsions of the second and third victims and their interactions with others. As in many Rendell novels, some of the non-series characters are psychologically extraordinary, so that their motives, though consistent, are not easy to fathom.