Saïd takes over as chief of the BRI Versailles, an elite unit specialising in organised crime. Leading officers Badri, Julien, Vanessa and Socrate, he will not only have to prove his mettle but also excel at succeeding the former chief, Patrick.

After Sélim's murder, the team deal with the criminal gang to find the shooters; during Patrick's wife's funeral, Saïd uncovers the true nature of the bond that unites him and Éric Perez.

The team find the identity of the second shooter; Éric Perez reveals to Saïd that he knows the people who got Sélim murdered; Saïd and Julien are following a suspect when they come across Socrate about to intercept traffickers.

Socrate admits to Julien and Saïd that he was recruited to investigate several high-ranking narcotics officers suspected of covering up cocaine traffickers; Jordan, Éric Perez's eldest son, escapes an assassination attempt.

After the operation fails, Saïd is demoted, and Patrick takes over as chief of the squad again; Éric Perez is convinced that the El Hassani gang is responsible for the attack on his son and prepares for retaliation.

The team celebrate the success of the last operation; Saïd confides to his team that he made a deal with the El Hassani gang so that they could help him in his investigation; as Saïd takes over BRI again, the Perez clan lose one of its members.

Nina, Éric Perez's daughter, accuses one of the El Hassani brothers of the murder of one of her relatives; convinced of his innocence, Saïd warns him so that he can flee, and in exchange, he provides information, helping Socrate in his investigation.

Returning from the operation in Morocco, Patrick realises that he was manipulated by the Perez clan to put the El Hassani gang out of the game; Julien finds the trace of the informant who had double-crossed him, and the team prepares to question him.