The story of an extraordinary friendship between a bear and a mouse. In the usual bear world, bears, as a rule, are grouchy and glum. Ernest the Bear is different. He’s a musician, and he’d like to be cheerful, but he’s poor and often hungry. While searching for food, he catches a little mouse named Celestine, who ran away from the underground world of mice. So as not to end up in his belly, Celestine makes a deal with Ernest: if he doesn’t eat her, she’ll show him a place with loads of chocolate, candies and other sweets. Thus begins not only an incredible adventure, but also an unexpected friendship.