Plot summary

In 2010, social problems such as violence, drugs and organized crime have overrun the poorer suburbs of Paris, especially a Banlieue commonly referred to as B13 (Banlieue 13, or District 13 or Borough 13 in English), a ghetto with a population of some two million. Unable to control B13, the authorities construct a high wall topped by barbed wire around the entire area, forcing the inhabitants within to survive without education, proper utilities, or police protection behind the containment wall. Police checkpoints stop anybody from going in or out.Three years later, an almost feudal system has developed amongst the street gangs of B13. The area is now flooded with hard drugs such as heroin and completely controlled by gangsters. Certain blocks are ruled over by various individuals and one high rise apartment block is looked after by an athletic and street-wise man known as Leïto (David Belle). Leïto hates drugs and injustice and wages a one-man war against a neighboring gang lord named Taha Bemamud (Bibi Naceri) to keep his own building and people safe and free of drugs. Leïto captures 20 kg of cocaine from Taha, worth over a million euro, which incites Taha to send his thugs to recover the merchandise, led by the towering K2 (Tony D'Amario). Leïto destroys the cocaine by using bleach and uses parkour to evade Taha's thugs through the building and across rooftops.Taha kidnaps Leïto's younger sister Lola (Dany Verissimo) to use against him, but Leïto manages to invade Taha's base, rescue his sister, and kidnap Taha in turn. Leïto takes Taha to the police office at the edge of the district perimeter, but the police are in the process of abandoning their position on orders from the French Ministry, and are also threefold outnumbered by Taha's gang. The police release Taha and allow him to take Lola with him to avoid a confrontation. In addition, they put Leïto in a cell also to contain the situation, but Leïto kills the police chief in the process for handing over Lola.Six months later, outside of B13 in the affluent areas of Paris, an undercover police captain named Damien Tomaso (Cyril Raffaelli) infiltrates an underground casino and attempts to arrest the gangster who owns it. His extraction procedure fails, however, forcing him to fight his way through an army of thugs to escape the casino. Upon the mission's completion, Damien immediately receives another assignment from his chief and also the Defence Secretary of France, Mr Krüger. He is told that Taha has stolen an experimental neutron bomb that is set to detonate in 24 hours. His mission is to convince Leïto, imprisoned for months, to lead him to Taha's base so that he can disarm the bomb.Damien attempts to pass himself off as a fellow prisoner and helps Leïto escape to B13, but Leïto sees through Damien's act and abandons him. After fighting off some of the local thugs, Damien locates Leïto and admits the truth. They team up to disarm the bomb and rescue Lola. The pair surrenders to Taha in order to gain access to his base. There, they discover that Taha has rigged the warhead to a missile launcher, pointed towards the center of Paris and is prepared to blackmail the government with it. Taha demands a high ransom, which is refused by Damien's government contact. The pair escape, and while Taha's thugs pursue them, he discovers that the government has emptied all of his offshore accounts in the Bahamas. One of Taha's men asks how Taha will pay them. Frustrated Taha trys to shoot the member who asked him that only noticing his gun to be unloaded. Taha offers money from a safe he possesses. Knowing that with Tahas accounts emptied and unable to have any reason to work for him the thugs shoot Taha. This leaves K2, a more sympathetic character, in charge and K2 has a moment of reconciliation with Leïto, suggesting that peace is possible in the future within B13.Leïto and Damien fight their way to the tower holding Lola and the bomb. Once there, Damien calls his contact to receive the deactivation code, 9293709B13. Leïto recognizes the code as a reference to the bomb's location (9293 is the district's area code), the day's date (7 September), and the district, B13. Leïto deduces that the government has set them up and the code will actually detonate the bomb instead of deactivating it. He fights Damien to prevent him from entering the code. The timer runs out and the bomb does not detonate, proving Leïto's theory.The pair return to the government building with the bomb and force Mr Krüger to admit that he had planned to blow up B13 as a means to get rid of it. The confession has been taped and is immediately broadcast by pirate television transmission. The pair's actions cause a major scandal that sparks public support for B13. Soon the rest of the government promises to tear down the containment wall and bring back schools and police to B13. Leïto and Damien depart as friends, and Lola kisses Damien to encourage him to visit B13 in the future.