It's summer, and Norimichi Shimada and his friends want to know if fireworks look round or flat from the side. They forge a plan to find the answer at Moshimo Festival's fireworks display. However, Norimichi finds himself conflicted when his classmate, Nazuna Oikawa, plans to run away from home and wants Norimichi to join her. When things go awry in their attempt to escape, a strange orb in Nazuna's possession gives them another chance at staying together.