Each week, Pierre and his friends organize what is called as "un dîner de cons". Everyone brings the dumbest guy he could find as a guest. Pierre thinks his champ -François Pignon- will steal the show.

After hiding his loot and getting thrown in jail, Ruby, a brooding outlaw encounters Quentin, a dim-witted and garrulous giant who befriends him. After Quentin botches a solo escape attempt, they make a break together. Unable to shake the clumsy Quentin Ruby is forced to take him along as he pursues his former partners in crime to avenge the death of the woman he loved and get to the money.

A man spreads the rumor of his fake homosexuality with the aid of his neighbor, to prevent his imminent firing at his work.