Antonio Barracano is a man who enforces his own law in the Sanità district, which is why he is recognized as the neighborhood's "mayor." He dispenses advice and opinions and solves the problems of poor people.

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.

Luca Cupiello, like every Christmas, prepares the crib, amid the disinterest of his wife Concetta and his son Tommasino. Ninuccia, the other daughter, writes a letter to her husband in which she communicates that she leaves him for her lover. The letter happens in the hands of Luca who hands it over to his son-in-law, who thus learns of his wife's betrayal. During lunch on Christmas Eve, the two rivals, who were confronted by Luca's carelessness, clash violently.