Domenico Greco is an unlucky stage actor drowning in debt, living as a freeloader in the home of his sister-in-law, Rosetta—the widow of his late brother—who has a nine-year-old son suffering from a heart condition. The only way to save the boy is through surgery in America, but the procedure costs 160,000 euros. In their desperation, they turn to Saint Januarius in prayer, begging for a miracle. The saint seemingly "responds," giving them the green light to "take" one of the jewels from his miter—kept alongside his famous treasure in the church crypt. In reality, it is merely the voice of a parking attendant echoing through the nave—a sound that Domenico and Rosetta mistake for a message from Saint Januarius. Joined by Ferdinando, Cesare, and Claudia, they embark on a "treasure hunt" that takes them from Naples to Turin, and eventually to Cannes, on the French Riviera.