Ernest and Celestine, best friends who are a bear and a mouse respectively, travel to Ernest's hometown to fix his broken violin. However, they are shocked to discover that music has been outlawed. With the help of new allies and a mysterious criminal, they endeavor to bring joy and music back to the bear country.

In a world where mice are taught to fear bears, a young mouse named Celestine forms an unlikely friendship with a kind-hearted bear named Ernest. Together, they navigate the challenges of prejudice and prove that friendship knows no bounds.

Ernest is a big bear from Charabie. He likes playing music and eating marmalade. He lives with Celestine, a little orphan mouse, and they share his house. Our two friends never get bored! When the first snowflakes start to fall they need to prepare for Ernest’s hibernation: they must take care of Bibi, their wild goose, who will fly away before the big winter, prepare cakes for Ernest and go to the mice’s ball to celebrate the first day of winter.