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.