A garage owner maintains his business as a front for his gang of criminals.

Louis Bertain is the owner of a Paris garage which is the front for a robbery gang. He and his accomplices are careful to keep up a civic veneer by day, indulging in criminal activities only when "the red light is on" at night. This status quo is upset when one of the gang members becomes convinced that Louis' younger brother is a police informer.

In Paris, Louis Bertain is the owner of a legitimate garage business, but secretly is the chief of a gang of thieves composed by the sadistic Pepito; the coward Frédo; and Raymond, the sailor. Louis is a bon-vivant that lives with his mother Ms. Bertain and his young brother Pierre, who is a small-time forger that is on probation. When Pierre visits his girlfriend in Paris, the easy manicurist Hélène, he breaks his parole and the police tries to force him to become an informer, but Pierre declines the offer. While planning the next rob with Pepito, Louis notes that Pierre has overheard their conversation, but Pierre denies. The robbery goes awry, with two murders, and the police arrest Louis that finds who has denounced them. But Pepito believes Pierre did and is hunting him down.—Claudio Carvalho, Rio de Janeiro, Brazil