A successful businessman, Domenico, has a tumultuous affair with a minor, Filumena, and eventually sets her up as his mistress. She secretly bears three children, raising them with nannies. When Domenico plans to marry another woman, Filumena tricks him into marriage by faking a terminal illness. After annulment, she reveals she has three children, claiming one is his, but refuses to disclose which one. Domenico, now uncertain, decides to remarry Filumena willingly.