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.

In a lively shopping center, proprietors and customers are bustling, including three women vying for a man's heart with song and dance.