School children Norimichi, Yûsuke and Jun'ichi want to know if fireworks look round or flat from the side. They make a plan to find the answer at a fireworks display, while Nazuna schemes to run away with Norimichi or Yûsuke, whoever win at the pool. This film tells the story of a schoolgirl who finds a pretty transparent ball by the sea, on the day of a fireworks display of a religious festival in a seaside town in Japan. She plans to run away from home to escape from her unhappy home, as her mother is about to remarry for the third time. However, her escape fails until her male classmate finds out the supernatural power that the transparent ball has.