Inspector Cockrill is called in to sort out which family member had the most motive to kill their unpopular Belgian house guest.
Few were disappointed when Raoul Vernet was found with his head bashed in, dead in a pool of his own blood. On vacation in England, the Belgian seducer comes to visit Matilda, an old flame from a few years before. She agrees despite suspicions that Vernet has been deploying his legendary charm on another member of the family: young Rosie, who has returned from her Swiss boarding school carrying a child.
None of the family members were in the house when Raoul was killed, but all were within a fog-choked London mile. Rosie calls in the brilliant Inspector Cockrill to clear the family’s name, but what he finds is a twisted clan of seven people, each as likely to laugh at a murder as commit one.