Joseph Vadassy, a Yugoslav language teacher and amateur photographer, finally treats himself to a vacation after years of waiting. He chooses a small hotel on the French Riviera. However, just two days after his arrival, he is suddenly arrested while trying to develop his first vacation photos at a drugstore. The accusation: he is a spy and poses a threat to French national security. Vadassy's only chance to prove his innocence is to strike a deal with the police. As an undercover investigator, he is sent back to his hotel to uncover the real spy. But who is a friend and who is an enemy?.