When the kitten Binou accidentally soils his favorite doggie, Mr. Mou, the mouse Toupie (Marc Labrche) calls on Dorothe (Anne Dorval), a cow living in a magic lamp, to get rid of the stain. However, because of a misunderstanding, it is the whole doggie that disappears. Toopy, Binoo and Dorothy must therefore go to the World of Lost Objects to find the precious stuffed animal. During this incredible adventure, the trio meet two gull twins, Jacques-Henri (Xavier Dolan) and Jean-Jacques (Stphane Rousseau), who are looking for their dad, as well as the mare Magnifique Princesse (Genevive Schmidt), whose dance partner has disappeared.