10-year-old Clémence finds an orphaned kitten in the attic of her Paris apartment building. Without further ado, she takes the cute fur ball in with her and names him Lou. The two become best friends and are inseparable from then on - and so Lou is even allowed to accompany Clémence and her parents to the country, where they want to spend the holidays together. There, the curious house cat enjoys his forays through the surrounding forests, where he makes friends with the little white cat Câline and experiences many exciting adventures in which he has to brave a number of dangers.