The scientist Marta Ventura, a friend of Diana, is found murdered at the Center of Geodesy of Matera. Accompanied - by Bartolini, a new reinforcement of the PG, Imma begins to investigate on several tracks but the truth, which has come to light thanks to a casual discovery by Diana, will however be completely different from the hypothesis initially pursued. In the prosecutor's office, tempers are in turmoil, Diana is shocked by the death of her friend, Imma thinks that Calogiuri is cheating on Jessica with the newcomer, Bartolini, and she lectures him. Samuel in the meantime returns to Matera for Valentina and discovers that the girl he still loves is courted by Gabriele, while Pietro is happy as never before, he has realized his dream, but it is a happiness that does not last long.

Imma investigates a strange theft in the home of a friend of her mother-in-law, whose stolen goods reappear intact a few days later while a man, Ulysses Delillo, is found dead in his artisan workshop. The two cases are linked and the yellow solution comes thanks to the proverbial memory of Tataranni. In the meantime, an act of courage, which proves decisive in the trial of Romaniello, forces Samuel to leave Matera, which Valentina blames her mother for.

It is Halloween evening and Pietro has taken Imma to see the family lamione where he wants to open the jazz club when two gunshots echo in the air: shortly after, the two run into a woman emerging from a nearby alley. Palazzo Sinagra, a building inside which a murder is discovered the next day. Between ghost stories, ex lovers, ex friends, séances, village gossip and old misanthropes, Imma investigates supported by a Calogiuri a little distracted by her relationship with Jessica.

Imma and Pietro return from a weekend in Paris where they tried to distract Valentina, still shaken by the separation from Samuel. But as soon as Imma sets foot in the house, she is immediately summoned on a case of murder that took place during the transhumance and which has the chief prosecutor Vitali as a witness. In addition to the investigation, Imma will have to clarify the delicate relationship with Marshal Calogiuri and, as if that were not enough, Pietro also seems to want to change his life.