Once upon a time in an ancient forest, there lived a little monkey. And this little monkey would run, jump, climb trees, dive in the lake, and chase butterflies—all day long! She would yawn and yawn as the sun set. The other animals would ask her, “Why are you so tired, little monkey? You should go to sleep.” But she would respond: “I’m not tired in the least. . . . So I don’t need to go to sleep.” In the trees, she'd sway under the stars as her friends' eyes shut all around her. Does the day have to end? Will the little monkey give into her yawns and her heavy eyelids, or will she play all night?