Taichi Sakamoto and Chika Koda have been dating since their second year of junior high.

After successfully navigating high school entrance exams and gaining admission to the same high school, Taichi, who dedicates himself to kendo club activities and his studies, and Chika, who isn't involved in any clubs, slowly begin to drift apart.

By the time Taichi realized this rift had already become irreparable, it was too late.

Taichi, tormented by his pain, managed to overcome his struggles by setting a single goal. However, when Chika, in turn, learned of this, she too realized it was already too late.