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.

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.