Francesca, a magistrate, seems happily married to a successful and wealthy engineer. They prepare to spend a holiday together when Francesca is instructed to shed light on the mysterious death of a girl, Rosa Franceschi, who threw herself from the terrace of her house. Francesca interrogates friends and neighbours of the victim, especially Veronica Marini who, living opposite the victim's apartment, followed the whole story. This is how she discovers her husband's affair with Rosa Franceschi and her involvement in the girl's suicide or murder.