At an auction house in Bath, England, a large slab of carved stone is up for sale. At the height of what turns into very competitive bidding, there is a holdup attempt by three masked raiders who are trying to steal the stone. They shoot and kill the highest bidder, a professor who has recognized the female figure carved in the stone as the Wife of Bath from Chaucer's Canterbury Tales. The masked would-be thieves flee, leaving the stone behind.

Peter Diamond and his team are assigned to investigate, and the stone is moved into Diamond's office so he can research its origins. The carving causes such difficulties that he starts to think it has jinxed him. Meanwhile, as Diamond's leads take him to Chaucer's house in Somerset, his intrepid colleague Ingeborg goes undercover to try to track down the source of the handgun used in the fatal murder.