The action takes place in post-war Italy, in a small Sicilian town. Apothecary Manno receives an anonymous letter, where he is threatened with death, without going into an explanation of the reasons. Friends of the pharmacist – Don Luigi Corvaya, Pecorilla’s notary, Laurent’s teacher, Rosello’s lawyer, Dr. Rosho – consider the anonymous letter an evil joke. Manno himself is inclined to think that they want to intimidate him with the intention of daring him to hunt – a few days later the season opens, and envious people, as always, are making jokes. However, just in case, the pharmacist notifies the sergeant of the Carabineros about the incident, and when he unfolds the letter, Paolo Laurana sees on the reverse side of the sheet the word “Unicuique”, typed with a characteristic typographical font.
On August 23, 1964, the day of the opening of the hunting season, the druggist Manno and his constant partner, Dr. Rosho, are found dead. The author of the anonymous letter brought his threat to execution, and the inhabitants of the town begin to wonder what the late apothecary did. Everyone pities the poor doctor who suffered for others’ sins. The police are also zealously taken over. The case: both victims occupied a prominent position and enjoyed general respect. In addition, Dr. Rosho has an influential family: he himself is the son of a well-known oculist professor, and his wife is the niece of the canon and the cousin of lawyer Rosello.
Through concerted efforts, the police and city residents find the solution to the murder: the apothecary was clearly betraying his ugly withered wife, and some jealous killer killed him. The lack of evidence and the beautiful reputation of the deceased do not bother anyone: once it reached the point of killing, it means that it’s not clean. Only Laurana takes a different view: although Sicilian instinct calls for caution, it detects in roundabout ways that the Catholic newspaper Osservatore Romano is written by only two people – a canon and a parish priest.
The priest’s numbers in the last month are safe and sound. Laurana is fascinated by the subtitle “Unicuique suum”. At the canon, he is in for a failure: in this house the newspapers read are becoming a household item. The Canon is firmly convinced that the pharmacist paid for a love affair, and that the husband of his beloved niece simply turned upside down on the assassin.
On this investigation could end, but, unfortunately, Laurana was lucky. This quiet and shy teacher of Italian in the town is respected, but he has no close friends. With Dr. Roshoe, he was associated with school memories – they studied together at the gymnasium and at the Lyceum. After the death of Rosh Laurent feels a feeling of emptiness and pain – it was almost the only person with whom he could discuss literary novelties or political events. Laurana’s personal life did not come about because of a selfish and jealous mother – on the threshold of the fortieth he remains for her a naive and inexperienced boy, not ripe for marriage.
In September, Laurana arrives in Palermo to take exams at the Lyceum. In the restaurant he meets a former school friend – now a member of parliament from the Communist Party. Rosho voted for the Communists, although he hid it out of respect for his wife’s relatives. Shortly before his death, the doctor visited Rome to meet with the deputy and find out whether it is possible to put in the newspaper expository materials about one of the most eminent citizens of the town, who holds the whole province and is involved in a number of dirty deeds.
Upon returning home, Laurana tells of her discovery to Rosello’s lawyer. He burns with a desire to take revenge on the unknown murderer. The beautiful widow of the doctor also comes to the excitement, for before she sincerely believed that...her husband died because of the amateur adventures of the apothecary. Signora Louise even allows Laura to look at the papers of the deceased, although she is most upset by the version that the apothecary was a false bait-everyone knew in the town that Manno and Roshoch were being hunted together.
Laurana appeals for help to the parish priest, who is treated with sympathy, despite his anti-clerical beliefs. He says that the most influential person in the province is the lawyer Rosello, who has achieved a high position by bribes, bribes and other machinations. Laurana suddenly opens his eyes: the town has been rumored for a long time that a lawyer and his cousin love each other from a young age, but the canon opposed marriage between close relatives, so Louise married Dr. Rosho. The beauty of this woman immediately aroused Laurana’s keen desire, and now this feeling was filled with horror – no doubt she was an accomplice in a cruel and treacherous crime.
-Rock case once again comes to the aid of Laurana. Having decided to get a driver’s license, he goes to the Palace of Justice and collides on the stairs with a lawyer Rosello, who descends down into the company of two men. Laurana knows the deputy Abello, famous for his scholarship, but sees his companion for the first time. This man with a broad rough face smokes cigars “Branka” – on the spot of the murder of the apothecary Manko and Dr. Rosho, a cigarette butt was found just this cigar. Soon Laurana finds out that she was not mistaken in her assumptions: a man who smoked cigars is a member of the local mafia.
After meeting in the Palace of Justice, Rosellot’s lawyer begins to avoid Laurent. On the contrary, the beautiful Signora Louise shows keen interest to him. Laurana almost regrets Rosello and does not intend to report: he has a deep disgust for the law and, like all Sicilians, at heart thinks the double-barreled gun is the best way to fight for justice. In the beginning of November, Laurana goes to classes and on a trip bus, she notices with surprise the widow of Rosh. Signora Louise confesses that she thought a lot about her husband’s trip to Rome, and recently she managed to find behind the books the doctor’s secret diary. Now she had no doubt: the murder was most likely arranged by Cousin Rosello. Laurana does not believe her ears: this adorable woman is pure – in vain he insulted her with suspicions. They agree on a date at the cafe “Romero” at seven o’clock in the evening. Laurana is in a state of excitement waiting until half past nine – Louise is gone, and anxiety for her life is growing in him. He goes to the station square, and then a resident of the town, familiar to him in person, but not by name, kindly offers a ride.
The case of the disappearance of Paolo Laurana has to be closed: he was seen in the cafe “Romeris”, and he was obviously waiting for someone – apparently, it was a love meeting. Perhaps, he will return home, like a walking cat in March. The police do not know that Laurana’s body lies at the bottom of an abandoned sulfur mine.
A year later, on the day of Maria’s wedding, the canon of Rosello, as usual, gathers friends. The mourning is over, and you can announce the engagement of the nephew of the lawyer with her niece Louise. Notary Pecorilla and don Luigi Corvaya come to the balcony. Both are eager to share the secret: the poor druggist was not involved – Rosho found a wife with a cousin at the scene of the crime and demanded that Rosello was removed from the town, otherwise the press will be informed of his dirty deeds. As for the unfortunate Laurana, he was just a fool.