The film features the voices of Lina Boudreault, Mari-Lou Gauthier, Michèle Caucheteux, Jean-Claude Donda, Michel Robin, and Monica Viegas.

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.

They watch an old variety show on television featuring a trio of singers, the Triplets of Belleville (Rose, Blanche, and Violette).

Arriving in the United States penniless and hungry, Souza and the obese Bruno are adopted by the Triplets of Belleville, now elderly, and taken to their seedy apartment.

Souza joins their band, playing bicycle spokes like a dulcimer, to their refrigerator-shelf harp, newspaper percussion and vacuum-cleaner bagpipe.

With the help of the Triplets, Souza rescues the cyclists, who had been forced to pedal-power a gambling machine, and escape on the pedaling frame, pursued by the mobsters in Citroën sedans.

In a flashforward, an older Champion watches the TV again showing their adventure when they are leaving the city and remembers Souza asking once more if the film is finished.