Little 15-year-old Hiyori Nishiyama gets into an accident the day before her high school entrance ceremony, leaving her hospitalized with severe bone fractures that prevent her bones from growing. Due to her timid nature, even after recovering, she hesitates to attend class.

But when Hiyori finally decides to go to school for the first time in a year, things take an unexpected turn. As she introduces herself, she is abruptly interrupted by Yuushin Hirose, a tall and outgoing boy. Hiyori not only loses her chance to make a good impression on her classmates, but Yuushin ridicules her by comparing her to a baby bird. However, due to Yuushin's sociable nature, she slowly feels more at ease around her classmates. With Yuushin at her side, Hiyori hopes to accomplish her goal of making friends.