Jim Wormold is an expatriate Englishman living in pre-revolutionary Havana with his teenage daughter Milly. He owns a vacuum cleaner shop but isn't very successful so he accepts an offer from Hawthorne of the British Secret Service to recruit a network of agents in Cuba. Wormold hasn't got a clue where to start but when his friend Dr. Hasselbacher suggests that the best secrets are known to no one, he decides to manufacture a list of agents and provides fictional tales for the benefit of his masters in London. He is soon seen as the best agent in the Western Hemisphere but it all begins to unravel when the local police decode his cables and start rounding up his "network" and he learns that he is the target of a group out to kill him.