Lieutenant Abdel, Dali Benssalah, an Algerian-French soldier, stands at a press conference outside a police station after his 13-year-old brother Idir dies in hospital, apparently the result of a brutal beating by three policemen. He appeals for calm and restraint, but Karim, Sami Slimane, leads a group of youths to disrupt the moment—tossing a Molotov cocktail and raiding the station. They escape with a weapons locker, some tactical gear, and a police van, then return to Athena, the banlieue where Abdel grew up, determined to barricade themselves and the residents inside the towering housing complex.
CRS riot police are deployed to quash the uprising, while the youths respond with fireworks and improvised missiles, turning the streets and stairwells of Athena into a tense battleground. In the midst of the chaos, Moktar, a drug dealer, tries to move bags of contraband out of Athena. When the youths refuse to let him pass, Moktar and his gang take shelter in Athena’s shisha lounge and dig a hole to stash the contraband until the disturbance subsides.
Abdel returns to Athena to attend a memorial service for Idir. He sees Karim and attempts to speak, but the younger brother evades him as the memorial is overwhelmed by the violence outside. Abdel then helps to organize an evacuation and a safe haven for Athena’s residents, including Sébastien, a former terrorist in Syria whom Abdel takes in at Athena’s daycare center—Sébastien, Mehdi Abdelhakmi, becomes part of the makeshift shelter.
As night falls, the group of residents is led past riot police, but an altercation erupts and Abdel and others are kettled and arrested. The riot police push forward, but their units are eventually forced to retreat, and in the confusion, Jerôme, a young officer, is separated from his unit and captured by the youths. They film Jerôme and threaten to kill him unless the three policemen who beat Idir are identified. The on-site police commander ultimately orders Abdel's release, and he sneaks back into Athena to confront Karim about the violence he’s incited. He tries to leave with Jerôme, but the youths pursue them, forcing both into the safety of the shisha lounge once more.
Moktar greets Abdel and the truth comes to light: they are half-brothers. Moktar calls in his payroll-backed police allies, who agree to come rescue Jerôme. Karim, determined to recapture Jerôme, challenges Abdel through the security shutter while the others attempt a break-in through a side door. The standoff ends when Karim lunges at the arriving corrupt policemen and is shot dead, a brutal killing that magnifies Abdel’s rage.
Enraged by his brother’s death, Abdel savagely beats Moktar and takes Jerôme into his custody for the moment. He phones the police commander and orders Sébastien to aid the youths, while the commander warns that RAID and the military are being deployed to restore order. On a video call with the commander, Abdel points his gun at Jerôme and fires twice—but it becomes clear that he intentionally missed. Overcome by emotion, he makes no effort to stop Jerôme from leaving as the tactical units close in. In the ensuing chaos, makeshift bombs engineered by Sébastien blow out parts of the buildings, killing Abdel and several police officers.
In the film’s closing sequence, a van quietly records the beating of Idir, with the footage eventually circulating on social media. The apparent police “perpetrators” are revealed to be far-right instigators in disguise—an explosive reveal that they burned their uniforms in the van to hide their true identity, underscoring that the violence was a calculated attempt to ignite racial unrest.
