Summer break in a town by the sea. One day before a firework festival, classmates excitedly discuss whether fireworks are round or flat when they're viewed from the side. Their classmate Nazuna, who Norimichi has a crush on, is lost in her own thoughts after learning that her mother, who is getting remarried, is making her transfer schools. Nazuna asks Norimichi to run away with her but gets caught by her mother, who drags her home. Norimichi can’t do anything but watch helplessly. Norimichi, frustrated with himself for not helping Nazuna, throws a mysterious ball Nazuna found on the beach. Then suddenly, time gets rewound to the moment before Nazuna is forced to go home… What does fate have in store for Nazuna and Norimichi at the end of the day that keeps repeating itself? When fireworks light up the sky, a miracle of love occurs.