Filumena has lived for years with a wealthy pastry chef. She forces him to marry her, but he soon asks to annul the marriage. She then reveals that one of her children is his, making him obsessed to know which one.
Tonino Esposito is the son of the fearsome Camorra boss of Rione Sanità, Naples. Unlike him, however, Tonino is clumsy and utterly innocuous—a decent person at heart—and so when his father dies he's passed over in matters of succession. His pride wounded, he doesn't resign himself and tries to be his own boss, only managing to make a fool of himself. When he finds out that his daughter is dating to the son of the judge prosecuting the new boss, Tonino sees the opportunity to prove himself in front of his family and all of Naples.
When his girlfriend Giorgia leaves him for his boss, journalist Giulio suddenly finds himself without a woman and with no job. Determined to win back his ex, he attends Valeria's classes, who teaches single men the art of seduction, convinced that relationships between people are motivated by simple biological stimuli.
Donato, a scoundrel music manager, to escape the two henchmen of a boss who, due to his inefficiency, has caused him to lose a lot of money, taking advantage of a letter from his uncle the bishop, introduces himself to the parish priest of a village church, Don Dino, dressed as a priest, and pretends to have been sent there by the bishop as assistant parish priest. Don Dino's church is always empty. In fact, the town's faithful frequent the new church, run by Don Gabriele, a pimp priest who knows how to deal with people. Donato's arrival initially seems like the final blow for Don Dino's church: Donato doesn't know where to start a mass, he has never confessed or married anyone, the mere idea of performing an extreme unction scares him. Don Dino begins to argue with Donato: he seems anything but a priest. But little by little, Don Donato's extravagant ways, his open-mindedness as a "sinner", his mentality as a rock priest, begin to attract the faithful.