Police captain Laure Berthaud seizes the opportunity to redeem her tarnished reputation when the mutilated body of a young woman is discovered, and immediately launches a search with her squad for the sadistic killer. Meanwhile, Judge Roban's investigation into the case of a child bitten by a dog turns out to have broader implications. French detective drama, starring Caroline Proust.

Laure struggles to keep her team under control when a second woman is reported missing. Meanwhile, public prosecutor Pierre Clement pays the price for refusing to cave in to pressure, and Judge Roban's investigation into possible corruption causes discomfort in high places.

The identity of the second body is revealed to be that of missing girl Celia Morau and the police begin to search for a serial killer, delving into the Paris underworld for clues. With little progress in catching the culprit, Judge Roban threatens to hand the case over to the Serious Crime Squad, but an important breakthrough occurs.

The police manage to remand their prime suspect in custody, but a series of revelations threatens to jeopardise the solidity of their case. Meanwhile, Judge Roban's uncharacteristically hasty actions look set to compromise his impartiality, and Pierre Clement finds himself roped into dealing with an unusual case.

Judge Roban transfers the case to the Crime Squad after an alarming number of procedural blunders occur, while the police are due to release the main suspect. Laure's reaction is surprising, but she remains determined to catch the killer, and Gilou finds himself in trouble.

Laure continues to protest that the serial killer is still at large, despite the evidence and opposition from her team. Meanwhile, Clement defends a young offender with a troubled past and Judge Roban ploughs on with his corruption inquiry - sparing no one in the process.

Judge Roban asks CID to take charge of the investigation when new evidence comes to light and Laure is forced to take a back seat as Superintendent Bremor leads the case. Meanwhile, Pierre goes beyond the call of duty for his troubled client, and Judge Roban's pupil finds himself the target of a blackmailer.

The police concentrate their efforts on putting Niko's prostitution ring under surveillance in the hope of tracking down a man who is an essential link in the investigation. Meanwhile, Bremont puts pressure on Gilou, prompting Laure to jeopardise everything to help him, and Roban suspects someone may have betrayed him.

Former public prosecutor Pierre Clement finds himself on the wrong side of the law and turns for help to the most unscrupulous lawyer he knows. Police tighten their surveillance on Niko's prostitution ring as the killer prepares to strike again, while Judge Roban discovers hard evidence to support his inquiry into municipal corruption.

Police strive to pinpoint the connection between the elusive leader of Niko's prostitution ring and the killer. Tension mounts between Laure and Gilou as he prepares to the leave the team and Judge Roban uncovers proof of Arnaud's betrayal and his reaction is unforgiving.

The police finally close in on Niko's prostitution ring, but the killer evades custody leaving Laure in a race to get to him first. Judge Roban discovers that the moral high ground comes at a price, while Pierre finds Josephine has made a deal with Szabo to save him.