Yseut Haskell, a pretty but spiteful young actress with a talent for destroying men’s lives, is found dead in a college room just metres from the office of unconventional Oxford don and amateur detective, Gervase Fen. The victim is found wearing an unusual ring, a reproduction of a piece in the British Museum featuring a gold gilded fly. As they delve deeper into Yseut’s unhappy life, the police soon realise that anyone who knew her would have shot her, but can Fen discover who could have shot her?