Mrs. Valmondi celebrates the engagement of her adopted daughter Giulia with the Couth Lanzoni. A late-arriving visitor wishes to speak to her, however; his name is Canio. When Mrs Valmondi sees the stranger, she brushes him off brusquely, for Giulia is never to know who her real father is. But Canio, who has sat in jail for 20 years and who has never forgotten his daughter, begs for understanding as to why he murdered her mother and lover years before. Frau Valmondi remains hard though. Finally, Canio convinces the young Leoncavallo to leave the house and listen to his story.