Crime author Dick Markham is in love again; his beau the mysterious newcomer to the village Lesley Grant. When Grant accidentally shoots the fortune teller through the side of his tent at the local fair - following a very strange reaction to his predictions - Markham is soon forced to consider whether his mysterious partner may be harbouring a dark and dangerous past. When the fortune teller - having revealed himself to be a renowned pathologist in disguise - is found dead in the night in an impossible locked-room setup, it seems it is not just Grant that may be hiding something from the rest of the village. Lured by the scent of the impossible case, Dr Gideon Fell arrives from London to match wits with a meticulous killer at large.