In the future, the most dangerous slums in Paris are surrounded by walls, with District B13 being one of the worst. It is ruled by the cruel crime boss Taha, and a young idealist named Leïto is set on bringing him down. When Taha kidnaps Leïto's sister, Lola, during a rescue attempt, betrayal leads to Leïto's arrest, leaving Lola in Taha's grip. Six months later, an exceptional undercover officer named Damien receives a critical assignment: Taha has stolen a neutron bomb in District B13, which is set to explode in under 24 hours.
With time running out, Damien and Leïto must collaborate to locate and neutralize the bomb, but the situation involves more complexities than they realize. In 2010, the unsafe areas on the outskirts of Paris are enclosed by walls. The residents lack access to schools, hospitals, and even police protection, with these neighborhoods being controlled by drug lords. In the 13th District, Leito is an upright man living in a tidy building who refuses to allow drug dealers in his area.
After he destroys one million Euros worth of heroin belonging to Taha Bemamud, the criminal kidnaps Leito's sister Lola, and corrupt police officers arrest Leito. Six months later, tough and honest Capt. Damien Tomaso is tasked with locating and neutralizing a stolen bomb that threatens to obliterate the 13th District and its two million residents. Alongside Leito, he must confront Taha's gang and uncover a vile secret linked to the bomb theft.