Darling, if ever I've met a group of potential murderers anywhere, it's the Bloodhounds.' Thus says one of the members of the Bloodhounds of Bath, a society that meets in a crypt to discuss crime novels. But to their latest recruit, they seem just a gaggle of dotty misfits, until one of them reveals that he is in possession of an immensely valuable stamp, recently stolen from the Postal Museum.

Then theft is overtaken by murder when the corpse of one of the Bloodhounds is found in a locked houseboat, with the only key in the possession of a man with a perfect alibi. Burly Peter Diamond finds himself embroiled in a mystery evoking the classic crime puzzles of John Dickson Carr.