Jim Wormold (Alec Guinness) is an Englishman living in Havana before the revolution. With him is his young teenage daughter Milly (Maureen O’Hara). His business is not very successful and Milly likes to spend more money than she should. Desperate, he accepts an assignment from the British Secret Service. His mission is to recruit a number of agents in Cuba. Not knowing where to start, he creates a bogus list of agents and stories to go with each name for the agency in London. He is soon heralded as the best agent in the Service. When police decode his messages and find out what he is up to they start to arrest the people on his list. What’s worse is that Wormold hiimself learns he has become a target for murder.