When Aoi and Kiichi, high schoolers in Kurashiki city, come across their friend Beniko trying to calm down her autistic brother Kyosuke, Aoi tries to help and makes the promise to shoot fireworks from Mount Tsurugata in the Bikan Historical Quarter. Upon hearing this, Beniko gets upset herself because she doesn’t believe this promise will be kept but Aoi becomes determined to make it happen. As surrounding adults see these young people put their spirits into this task, they are moved and the fireworks take on a greater meaning.
