In order to conquer Margaretella with expensive presents, a young man called Tore steals his mother's jewels but Margaretella seems to prefer Carluccio who challenges Tore to a duel and wounds him. Forgiven by his mother just before she dies, Tore takes revenge by killing Margaretella, but even in prison he can't stop thinking to his victim.

Nanninella, a young girl, is exploited and abused by her father, whom she maintains with her waitress salary. She falls madly in love with Tore, a handsome and upright man, whose friend Carluccio plots to have Nanninella for himself. Based on a popular Neapolitan song, ‘A Santanotte is the earliest extant feature film by Elvira Notari, Italy's first and most prolific female filmmaker.