Fireworks, Should We See it from the Side or the Bottom?

One summer day, a group of sixth-grade boys have an argument about whether fireworks are round or flat when viewed from different angles, and they embark on a journey for the answer during the annual firework festival. Meanwhile, one of their classmates, Nazuna, is troubled by her parents' separation and decides to choose one of the boys—Norimichi or Yūsuke—to run away with, depending on who wins a race at the pool.