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.

The police make an appeal to the Press and get their hands on Elina's diary - which reveals she had friends in high places. Pierre discovers a connection between the murder victim and a childhood friend of his, now a wealthy businessman - and it seems they met the day before she died.

The police delve into the personal life of a businessman who burned to death in his own home, Clement struggles to conceal his friendship with a suspect in the Andrescu case, and Gilout's drug habit gets out of control. The mother of a murdered baby is accused of negligence.

A prominent ministerial adviser, who has links to prosecutor Pierre Clement's close friend Benoit Faye, joins the list of suspects for the ruthless killing of Elina Andrescu. Meanwhile, Captain Laure Berthaud comes up against lawyer Josephine Karlsson during an inquiry into a double murder.

The inquiry into Elina Andrescu's murder takes yet another disturbing turn when the body of her missing sister Sophia is found in a freezer. A distraught Ghislaine Androux is brought to trial in connection with the murder of her baby, but Judge Roban soon begins to regret meddling in the affair.

Pierre begins divorce proceedings after his estranged wife is implicated in a drug trafficking scandal. Josephine defends a man accused of committing brutal acts of torture, while Gilout's drug addiction tests Berthaud's patience

Pierre Clement unwittingly endangers Benoit Faye's life when he resolves to have his friend arrested in connection with the Andrescu case. Lawyer Josephine Karlsson is called in to defend a young man accused of rape, while Gilout is compromised by blackmailers.

With Benoit Faye in intensive care following an assassination attempt, the prosecution in the Andrescu case has lost its main witness. The events leading up to the sisters' double murder are reconstructed using Benoit's recollections.

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.

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.