Rosie can't wait to start kindergarten--she's had her pencils sharpened and her backpack ready for weeks. But suddenly, on the night before the big day, her tummy hurts. Rosie's mom reassures her that it's just butterflies in her belly, and she'll feel better soon. Much to Rosie's surprise, when she says hello to a new friend on the bus, a butterfly flies out of her mouth! As the day goes on, Rosie frees all her butterflies, and even helps another shy student let go of hers, too.