In 1931, gangster Angelo "Snaps" Provolone promises his dying father that he will go straight, turning his old crew into the loyal staff of a grand household at the Barnier mansion. At the Barnier mansion, Bertrand Barnier Louis de Funès and his wife Mme Germaine Barnier Claude Gensac preside over Colette Barnier Agathe Natanson and Oscar Roger Van Hool, who help run a bustling, ever-watchful domestic world. Snaps hopes that by reforming his operations into respectable, lawful work, he can donate a large cash sum to a bank, earn a seat on the board, and finally have an honest vocation that honors his promise to his father.
The morning unfolds with a tense mix of ambitions and schemes. Anthony Rossano, Snaps' young accountant, arrives demanding a dramatic raise and reveals a personal stake—he’s in love with Snaps' supposed daughter and plans to propose with a jewel-topped gift he allegedly stole from the books. Snaps, torn between old loyalties and new rules, erupts, and a plan to marry off his daughter to secure a future is hatched, all while he grapples with the weight of family and fortune.
Lisa, Snaps's daughter with Sofia, is a headstrong, worldly-aspiring young woman whose dreams of seeing the world collide with her father’s overprotective insistence on propriety. At the urging of the family’s maid, she pretends to be pregnant, hoping to force a change in her father’s stance and push him toward granting her independence. The plot thickens when Lisa reveals the supposed father of the baby is Oscar, the former chauffeur who’s now serving overseas, throwing the household into a swirl of assumptions and bluffs.
Theresa enters the picture, a woman Anthony once wooed who confesses she lied about being Snaps’ daughter to impress him. Snaps, quick-witted and calculating, traps Anthony into agreeing to marry his imagined son-in-law and hand over the jewels to secure Lisa’s future, all while Theresa wrestles with her own feelings. When Theresa comes clean to Anthony about the deception, he misreads the gesture and believes love has been traded for wealth, so the couple’s relationship seems broken. Yet Anthony discovers a different, more honest path when he learns that Dr. Thornton Poole—Snaps’ sharp-tongued dialectician—might actually be a better match for Lisa, thanks to his globe-trotting lifestyle.
Meanwhile, the local police lieutenant Toomey eyes the mansion with wary suspicion, convinced Snaps will meet with Chicago mobsters. Vendetti, a rival gangster, shares that worry and keeps a close watch on the property. Soon, the comings and goings around the house, including a black bag that often changes hands with Nora’s identical bag of underwear, fuel mutual paranoia. Toomey and Vendetti both plot a strike on Snaps in the early afternoon, imagining the jewels as hidden loot or a smuggling operation.
In a flurry of swift moves, Anthony recovers the jewels and, with clever accounting, secures the payment of $50,000 to Snaps—an amount Snaps uses to provide a semblance of marriage and stability for Lisa. Theresa, drawn back to Anthony after the emotional dust settles, then helps piece together a reconciliation, while Poole and Lisa announce their own engagement, having fallen in love for real despite the earlier turmoil.
A new maid, Roxanne, arrives when Nora leaves to marry a business associate, and she proves to be an old flame of Snaps. Roxanne reveals she was once pregnant with Snaps’ child but never found the chance to tell him. Theresa, it turns out, is Roxanne’s grown daughter, which makes Theresa Snaps’ granddaughter in a twist that redefines the family’s ties and loyalties. The revelation adds a warm, if chaotic, thread to the celebrations.
The bankers finally arrive to discuss Snaps’ potential influence in the bank, but the tone shifts as Snaps senses a raw deal—no real power, no real respect for his money. The bankers’ meeting is interrupted by the looming threat of Toomey and Vendetti, who crash their way into the scene just as the tension peaks. The encounter ends with Toomey arresting Vendetti’s armed crew, exposing the fragility of Snaps’ dream of a clean, legitimate life.
Yet the pull of the old life proves irresistible. Despite his father’s wishes and the lure of respectable banking, Snaps realizes he would rather face the dangers of the underworld than endure the sterner constraints of the financial world. He chooses to abandon the fragile veneer of legitimacy and return to the world he knows best—crime and the adrenaline of risk.
The story culminates in a double wedding for Snaps’ two daughters, a moment of joy that is shadowed by the ongoing tug-of-war between law and the life he knows. Even Oscar, who at first objects to Lisa’s romance, is swept up in the festive mood as Snaps’ crew keeps watch, making sure the day ends with laughter and love. In the end, Snaps embraces the chaos and the thrill of his old world, finding that the bonds of family and loyalty outshine any number of respectable ambitions. The film closes on a note of celebration, with the family and friends gathered in a warm, noisy harmony as the future remains uncertain but promising for those who choose their path together.
