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.

Gérald, former champion of motorcycle competitions, after an accident that causes him to lose the use of his right becomes a trainer for young riders. But because he can not make enough money, he takes part in a burglary.