Three years after the disappearance of seventeen-year-old Tatiana, another young woman, Leïla, is found dead and horrifically mutilated near the Perpignan train station. Flore, a young investigator, begins her career in the police.

The team tightens their investigation around Olivio Palomyno, the key suspect in Leïla's murder. Flore, the young recruit, is assaulted during a hazing ritual but finds support in Sabueso, strengthening their bond.

The investigation takes a dramatic turn when a new disappearance occurs while Olivio Palomyno, the main suspect, is in prison. The team must reassess their theories, while Flore struggles to assert herself in a hostile environment.

As the world prepares to enter the year 2000, the investigation stalls. A profiler from Paris proposes bewildering theories. Flore, weakened by a recent assault, becomes more involved to push things forward.

The investigators race against time to arrest a new suspect. However, his confessions raise more questions than answers. Nora's body is found, but the investigation remains mired in uncertainties about the other victims.

After sixteen years of investigation, the team finally manages to arrest the perpetrator of two of the murders thanks to a DNA match. During a gruelling interrogation, Flore forces the suspect to confess to the murders of Leïla and Marianne.