Potto is painting a portrait of Hilda, and suddenly realizes that he can’t possibly finish without green - "the best colour." Hilda’s not so sure that green really is the best. She likes some other ones too. When the question comes in, "What’s the best colour?" it’s the perfect opportunity to visit children in an art class. Hilda and Potto come to realize that there’s no such thing as the "best" colour. Everyone can choose their own favourite.