Léon, the top hit man in New York, has earned a rep as an effective "cleaner". But when his next-door neighbors are wiped out by a loose-cannon DEA agent, he becomes the unwilling custodian of 12-year-old Mathilda. Before long, Mathilda's thoughts turn to revenge, and she considers following in Léon's footsteps.

Fred, a raffish safe blower, takes refuge in the Paris Metro after being chased by the henchmen of a shady businessman from whom he has just stolen some documents. While hiding out in the back rooms and conduits of the Metro, Fred encounters a subterranean society of eccentric characters and petty criminals.

Richard, a West Indian man in his forties, remembers "his war" in Algeria. More than twenty years later, he still carries internal trauma.