Police Chief Herville is found dead in a Chinese restaurant in the 13th arrondissement of Paris. Gilou must break the news to Laure, who is being treated in a police rehabilitation centre. Now in charge of the unit, Gilou begins investigating with new recruit Ali, who is fresh out of training. Meanwhile, Judge Roban returns to work from his time off sick only to find he is soon due to take compulsory retirement. And lawyer Joséphine struggles to adapt to life in prison while awaiting trial.

As the police identify that their top priority is to track down Ryan and his gang, Gilou agrees to work with Laure again, but she must find her place now that he and Ali are a team. Meanwhile, Edelman provides legal counsel to Joséphine to help her get out of prison.

Ryan is not telling the whole story, so Roban decides to lock him up. The banknotes recovered from the robbery lead police to take their investigation to a nearby housing estate. Meanwhile, a link is uncovered between Wang and Herville, and Joséphine builds a rapport with her cellmate, Lola.

Laure follows the drug traffickers’ courier to a warehouse in Aubervilliers, where the investigation suddenly acquires a new dimension. Meanwhile, still frail, she struggles to cope with the responsibilities in her personal life. Joséphine has a hearing with the judge. And Roban pursues a case of negligence at a hospital by involving the hospital director.

Police work to uncover the role of Ryan's elder brother Fouad in the money-laundering scheme. Beckriche calls on his former colleagues at the fraud squad to assist in the investigation, but his decision is controversial. Laure and Gilou make a breakthrough arrest, while Edelman presses for a crime scene reconstruction he thinks will help Joséphine.

The money-laundering operation closes ranks. Beckriche orders his team to let the fraud squad take the lead with their investigation, but will his colleagues comply? Out of prison, Joséphine finds herself trying to pick up the pieces of her personal and professional life.

Following the debacle resulting in Fouad's death, the team is taken off the investigation. Laure is increasingly concerned about Lebrion's interference, while Joséphine realises she also has reasons not to trust Edelman.

Roban falls into a trap set by Joséphine and Edelman, whose professional partnership is now, however, on the rocks. Laure and Gilou continue to work on the investigation they've officially been taken off, identifying a suspect who may have been involved in the money-laundering operation. Beckriche's loyalty to his former boss is put to the test.

With his role in the investigation irreparably tarnished, Roban loses his grip on the case. Laure and Gilou go ever further out on a limb with a rogue decision to reactivate the now-dormant money-laundering operation. Joséphine, who now works for Solignac, continues to set traps.

Laure and Gilou sink deeper into taking illegal measures, risking yet more grave repercussions. Their former team member Tintin is tasked with investigating their methods. Meanwhile, Joséphine does her best to protect Lola. However, she proves to be a most uncooperative defendant - for reasons that Joséphine understands only too well.

When Laure and Gilou, under investigation by Internal Affairs, are taken into custody, Tintin is torn between his loyalties to his former colleagues and his new job. Josephine also faces a moral decision about how best to fight Lola's case.

As police close in, Cann plans to make a run for it. But first, he reaches out to Edelman, asking for his help. Josephine intervenes in the investigation but is not immediately trusted. Meanwhile, Laure and Gilou still have not been cleared of wrongdoing by Internal Affairs.

When a charred corpse is found in the boot of a car in the suburbs, Berthaud's police team are called to the scene along with the prosecutors Roban and Clement. So begins an investigation which forces the team into the broken, gang-ruled suburbs of Paris, and once more to the door of shady lawyer Josephine Karlsson.

Laure is disciplined for her use of force on a suspect and comes into conflict with Clement over his compromising newspaper interview. Karlsson is taken into Szabo's pay as his accomplice in representing the drug ring. Judge Roban uses his usual cunning in investigating a strange rape allegation.

Laure's net is closing in on Aziz, but she still has to call in a favour from Roban to help her hold a suspect. A police stakeout on the estate goes dangerously wrong. Pierre is faced with a moral dilemma as his star begins to rise. Karlsson continues to play a dangerous game with Szabo's shady clients.

Rachid is dead, causing problems for both Karlsson and the police. Gilou has to investigate a murder linked to a gay nightclub.

The mysterious north African, Samy, arrives from Special Branch to help with the investigation into the Larbi crime family. Aziz is still out of control and finally pushes one of his young gang members too far - the team are called to a street shooting and the perpetrator is a sinister teenager.

Samy goes deep undercover with the Larbi gang. The police are closing in on Aziz, but as usual nothing is straightforward. Josephine Karlsson is up to her neck in the dealings of the Larbi gang. Clement plays a clever game behind the scenes.

As Samy's undercover operation nears its conclusion, the team prepares to arrest the Larbi brothers - but an unforeseen complication occurs and the detective's identity is called into question.

Samy tries to allay the suspicions of the Larbi brothers as the operation reaches its conclusion while Karlsson continues to walk a fine line. Last in the series.

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 struggle to hold on to their suspect when he is hospitalised, while prostitutes who have been exploited by a criminal gang still believe the killer is at large. Judge Roban finds his head swayed by his heart as his personal life starts to have an impact on his work, while former public prosecutor Pierre Clement joins forces with an unscrupulous solicitor.

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.