Death and decapitation seem to go hand in hand in the Devon village of Aller. When the first victim's head is sent floating down the river, the village's rural calm is shattered. Soon the corpses are multiplying and the entire community is involved in the murder hunt. While the rector, the major, the police and a journalist, desperate for the scoop of the century, chase false trails, it is left to Gervase Fen, Oxford don and amateur criminologist, to uncover the sordid truth.