In the early 1950s, the popular radio show "La Kermesse aux Étoiles", hosted by the famous Jean Nohain, mixing lottery games and performances of various artists, will be disrupted by the adventures of a man and his fiancée seeking to recover a dangerous bottle of perfume (explosive) which was unfortunately mixed with the prizes to be won ...

Alex Grégoire is a timid insurance company clerk who shares his uneventful life between his wife Angèle, his colleagues and his passion for crosswords. But all of a sudden his existence changes dramatically. First because he wins a crossword competition. Second because a jewel thief, Charles Tuffal, thinks he recognizes in him a former accomplice. From that moment "uneventful" is not the best adjective to qualify Alex's life anymore...