Clarissa, the wife of a Foreign Office diplomat, is given to daudreaming. 'Supposing I were to come down one morning and find a dead body in the library, what should I do?' she muses.

Clarissa has her chance to find out when she discovers a body in her drawing-room. Desperate to dispose of it, she attempts to persuade her house guests to become accessories and accomplices. As the search begins for the murderer in their midst, the house party is interrupted by the arrival of a police inspector, who needs convincing that there has been no murder at all...