One Sunday morning in Catania, Bruno Costa, an employee of a telephone company, goes to the house of Anna Zanchi, the woman he is madly in love with, and finds her butchered corpse. Afraid of being accused of the murder, Bruno runs away. The police commissioner Giacomo Chimenti arrives at the crime scene and is entrusted with the investigation. Based on the homonymous story by Andrea Camilleri.

Sam is the cook of a farmhouse where a man is killed. Initially suspected of the murder, he finds himself investigating the fact pushed by Zen, an environmentalist friend of the victim.