The fifty year old public prosecutor Valerio Grau dies poisoned at the bar of the Law Court in Sassari, right after a coffee he was having with Lauretta, a magistrate herself and his lover for the last ten years. The Head Prosecutor Pani entrusts Piero with the inquiry.
Piero is a judge at Palermo Law Court, he has no ambition and not much of a career so far, this is a good chance for him to improve his position. So he goes to Sassari and takes on the inquiry.
Valerio Grau is buried next to his beloved sister Biba, who committed suicide just a year before. According to the autopsy and the lab reports, the cyanide that had killed Valerio was contained in the slimming pills he used to take every spring. A search of his house showed that Valerio collected illegal archaeological pieces. In the meantime Piero finds out that Head Prosecutor Pani’s real goal is not so much finding the killer, but damaging Giomaria Martinez, president of the Court of Appeal, Lauretta’s betrayed husband. Nevertheless Piero decides to continue his work. On his side, there are Piras, an officer of Carabinieri a faithful servant of the state, and Ilio Melis, a young magistrate under training. Piero discovers that some years before Grau had chosen not to prosecute against a defendant who had many circumstantial proofs against him. Piero has some suspicions because that man, Pons, was accused of illegally trading in archaeological artefacts. One night Piero goes to Valerio’s house and finds Lauretta’s letters in a drawer. He decides not to talk about them and hides them in his office. The following morning he discovers that Pani has found them and has summoned Lauretta to question her.
Pani interrogates her, reminding her episodes of her affair with Valerio and accusing her of killing him. Piero now understands that Pani’s hostility will relieve him if the inquiry. He says good bye to Lauretta and Martinez and decides to go back to Valerio’s house, as a last gesture. While he walks around the house he trips over one of the small statues breaking it, so he realises that it is false. Piero goes back to question Pons who tells him that the deceased magistrate had recently had bad financial problems, that’s why he had been forced to sell his artefacts and substitute them with copies.
Besides Pons insinuates a heavy suspicion about the ambiguous relationship between Valerio and his sister Biba. Pietro is sure that the solution to the mystery is at Bosa, in Valerio’s family house. It is there that the case finds its logic explanation.
From the novel of Salvatore Mannuzzo.