Evening Fireworks

Following the story told through the Shounenki song 宵花火 (yoihanabi), or as much of it as I can understand.
Basically, Kou notices a girl while he's at a fireworks festival and pursues her throughout the evening. They finally meet and end up spending a magical night together before they must part ways after the fireworks display.
**I think that means this isn't an original storyline.**
**I don't own Shounenki, the members, or the song ((especially unfortunate about those first two.))**