Synopsis

High school students Aoi, Kiichi, and Beniko live in Kurashiki City, Okayama Prefecture.

One day, Aoi and Kiichi make a spontaneous promise to calm Beniko’s autistic older brother, Kyon-kun, saying they will launch fireworks from Mount Tsurugata in the Bikan Historical Quarter. However, Beniko bursts into tears, furious that an empty promise would only hurt her brother.

Shocked, Aoi and Kiichi decide to make the promise a reality.
Seizing the opportunity, the two ask for support—only to be told, “Gather 100 people who truly believe in this.”

What started as a small promise sparks a movement, igniting the passion of the youth, inspiring the adults, and spreading throughout the town. If this happens, the fireworks will become something far greater than just a display…