Karada is an elementary school student who acts mature for her age, and asks that people treat her like an adult. While praying at a wishing stone (negai ishi), she meets an older girl named Shouko. Shouko had moved to this small town to start a new life, but the same day she meets Karada, she encounters her brother, Hiro. Tension builds as Shouko and Hiro reflect on their past relationship while sending Karada home alone, and by the end of the day, both Shouko and Karada end up at the wishing stone hoping for change. Karada wishes to become an adult, while Shouko wishes for things to go back as they were in the past. That night under the bright moon, the wishing stone grants their wish, and an unbelievable transformation occurs: Shouko becomes a child and Karada becomes an adult. Now the two girls must struggle with their new bodies while finding a way to return back to what they once were.