Josef Vadassy, a Hungarian refugee and language teacher living in France, is enjoying his first break for years in a small hotel on the Riviera. But when he takes his holiday photographs to be developed at a local chemists, he suddenly finds himself mistaken for a Gestapo agent and a charge of espionage is levelled at him. To prove himself innocent to the French police, he must discover which one of his fellow guests at his pension is the real spy. As he desperately tries to uncover the true culprit's identity, Vadassy must risk his job, his safety and everything he holds dear.