At the BRI Versailles, a unit specializing in organized crime, Saïd leads a team of young cops. He will lead Badri, Vanessa, Julien and Socrate and will have to take up the challenge of succeeding Patrick, a respected former chef. Éric Perez, an informant thug from Patrick, tries to warn Saïd that a gang war threatens to set the capital ablaze. A shooting breaks out, a man and a child are on the ground.
After the shooting, the BRI must deal with the crime squad to find the two shooters. Socrates obtains the name of one of the shooters involved: Aslan. The group tails him but the situation gets out of hand.
Thanks to the intelligence services, the BRI obtains the name of the second shooter. Éric Perez, Patrick's informant, assures Saïd that he knows who ordered the shooting. As Saïd and Julien follow a suspect, they come across Socrate going it alone.
Socrates confesses to his team that he was actually recruited to investigate high-ranking narcotics agents suspected of corruption. For his part, the eldest son of Éric Perez survives an assassination attempt. Moreover, informed by an informant from Julien, the team prepares to intervene in the robbery of a jewelry store. Saïd must carry out his operation at all costs.
After the failure of the operation, Saïd is demoted and Patrick takes over as head of the group. Éric Perez is convinced that the El Hassani gang is responsible for the attack on his son. He is plotting his revenge. For their part, Saïd and Julien locate the hideout of Julien's informant, responsible for the failure of the operation, the BRI intervenes and apprehends his accomplices but the latter remains untraceable.
The team celebrates the relative success of the previous day's operation. Saïd tells his team that he made a deal with the El Hassani to help him investigate the shooting. As Saïd takes over the leadership of the group, the Perez clan loses one of its members.
Nina, the daughter of Éric Perez, accuses one of the El Hassani brothers of the murder of one of his relatives. Convinced of his innocence, Saïd warns him so that he can flee. In exchange, he delivers information helping Socrates in his investigation. Patrick and Badri, meanwhile, are sent by Ferracci to Morocco for a special operation.
Back from the operation in Morocco, Patrick realizes that he has been manipulated by the Perez clan to put the El Hassani offside. It is then that Julien finds the trace of the informant who had double-crossed him. The entire BRI team is preparing to question him.
