When Germany invades Holland in 1940, a British intelligence officer and two Dutch diamond merchants go to Amsterdam to persuade the Dutch diamond merchants to evacuate their diamond supplies to England.

Jean and Bill are a married couple trying to scrape a living. Out of the blue they receive a telegram informing them Bill's long-lost uncle has died and left them his business—a cinema in the town of Sloughborough. Unfortunately they can't sell it for the fortune they hoped as they discover it is falling down and almost worthless.

Jewel thieves, murder, and a manhunt swirl around a sailor off a cargo ship in post-war London.