Today marks Jooshin High School's 25th anniversary, and a grand celebration has been organized. Rian, as the owner's son, the event's chief guest, arrives in a luxurious sports car, the students and faculty members turn to greet him. However, Rian's gaze is drawn elsewhere—towards a small outdoor stage near the entrance of the school. There, under the soft glow of the setting sun, a girl is strumming a guitar and singing.

Rian has never seen her before, but something about her catches his eye.