The series opens with the murder that took place on the night of June 7, 1981 in the countryside near Scandicci: Carmela de Nuccio and Giovanni Foggi were shot dead while they were alone in their car.

Hopes that Mainardi would reveal the killer's identity faded with his death in the hospital. The prosecutor's office began pursuing a new lead, stemming from a 1968 crime.

Pia's disappearance shocks Renzo so much that uncovering the truth becomes his sole obsession. He quits his job to devote himself entirely to her search.

The prosecutor ordered a search of Pacciani's home and found a bullet compatible with those used by the monster.

In the aftermath of Pacciani's appeal trial, prosecutor Vigna, aware of the weakness of the evidence, decides to take a fresh look at the investigation and calls in Commissioner Michele Giuttari.

Renzo's passing is a hard blow for Winnie: the pain of losing her husband is compounded by the financial difficulties that force her to leave the house where she saw Pia grow up.