As Lidia investigates a mysterious poisoning at a prestigious boarding school, Jacopo digs deeper into their friend's death and Marianna uncovers a lie.
Enrico remains doubtful about running for Parliament while Prosecutor Fourneau and Lidia struggle to connect the victims of a series of brutal murders.
Despite Lidia's conflicted feelings for Fourneau, the murder of a prison guard forces them to collaborate again, as Jacopo edges closer to finding Nitti.
In the wake of a shooting, Fourneau takes over the Nitti investigation. Enrico receives an eminent guest, while Lidia and Jacopo race against the clock.
