Two bodies are found after a fatal dire on two narrow boats. Police suspect arson, and the discovery of a forged Turner landscape leads DCI Banks and DS Cabbott to connect the victims to an art forgery scam. Cabbot becomes involved with art expert Mark Keane, who is assising with the investigation. Banks, meanwhile, suspeccts that Patrick Aspern, father of one of the victims is deliberaately withholding vital invormation. A third victim is discovered and Banks, the subject of a possible complaint by the Asperns, is determined to identify the man behind the art forgery scam. Cabbot's relationship with Keane makes her a target for the killer, with nearly disastrous consequences.