The film features the voices of Michèle Caucheteux, Jean-Claude Donda, Michel Robin, and Monica Viegas. There is little dialogue; much of the narrative is conveyed through song and pantomime. It tells the story of Madame Souza, an elderly woman who goes on a quest to rescue her grandson Champion, a Tour de France cyclist, who has been kidnapped by the French mafia for gambling purposes and taken to the city of Belleville (an amalgam of New York City, Montreal and Quebec City). She is accompanied by Champion's loyal and obese hound, Bruno, and joined by the Triplets of Belleville, music hall singers from the 1930s, whom she meets in the city.