Sofia, Don Saverio's sister, confesses to her brother that she was the victim of a fateful event: while she accompanied her brother to Rome, while he was resting at a hotel, a terrible storm broke out during the night, accompanied by thunder and lightning. Frightened, she left her room to seek refuge in her brother's, when, after the lights went out, she accidentally entered a stranger's room in the darkness and fainted from fear of a violent clap of thunder. The unknown individual seized the opportunity and took advantage of her. From that turbulent encounter, Don Felice Sciosciammocca was born, Sofia's illegitimate son, now engaged to Marietta, Don Saverio's daughter.
