A quarrel between co-owners. This is the reason that unleash the anger of Rosa Bazzi and Olindo Romano, responsible of four murders. The victims, hit with a knife and a bar, are Raffaella Castagna, his son Youssef Marzouk, Raffaella’s mother Paola Galli and their neighbour Valeria Cherubini. At Fist Raffella’s husband, Azouz Marzouk, is wrongly charged of the murders, but he produces a valid alibi. It is at this point of the investigations that an unexpected witness steps in. Mario Frigerio, another neighbour of Rosa and Olindo, is seriously wounded with a knife on the same day of the other four killings. The murderers believe he’s dead but he is not. Thanks to his testimony investigators piece the facts together. One only question still remains with no answer: where Rosa and Olindo aware of what they were doing?