Lucy Church, the sole witness to a fatal robbery, is struck by a passing bus and her life lies in the balance as the thieves wait for a chance to finish her off.

After leaving the British Secret Service, David Somers (played by Trevor Howard) finds work cataloging butterflies at the country house of Nicholas and Jess Fenton. After the murder of a local gamekeeper, suspicion (wrongfully) falls on their niece, Sophie Malraux (Jean Simmons). Somers helps Sophie to escape arrest and they go on the run together. After a cross-country chase they arrive at a coastal city with the intention of leaving the country by ship. All's well that ends well after the true identity of the murderer is revealed.

A clever fortune-hunter with a penchant for murder does in his elderly, supposedly rich, wife and manages to get away with it. After an investigation results in a decision of 'accidental death', our crafty killer discovers that his late wife's 'fortune' is not what he thought it was. Driven to find another unsuspecting spouse; he discovers that his new bride, a widow, is no fool. When she tells him that she intends to keep her accounts separate from his, he is driven to contemplate murder once again