Two brothers (Albert Matterstock and Attila Hoerbiger), who are trapeze artists, are getting along just fine until Hoerbiger runs off with his brother's wife. Matterstock isn't very pleased when his wife is killed.
Three mice run, cavort, sing and dance around in the stores and restaurants a big city at night. They wind up in a café for an early-morning snack and stocking up on food provisions before they return to the safety of their den beneath a man-hole cover in the street.
In the village of Sableuse, the local manor has been bought out by a nouveau riche, Emile Cousinet. When his wife Lisette, a former music hall actress, flees to Paris with young Pierre de Sableuse, Cousinet asks Father Pellegrin, the village vicar, to bring the lost sheep back home.