Mishima Haruki and Honda Towa are new students at Aokisora High School and best friends. At a convenience store near their high school, Mishima runs into his classmate Mashiki Miharu, a girl he's recognized since he was little.

Disgusted by the irresponsible and talkative Honda, serious class representative Mami has been avoiding him. However, even when Mami begins avoiding him even more after a certain incident at the convenience store, Honda is undeterred.

When Honda spots Miharu having a friendly conversation with their classmate Sanagi Nasa in the waiting room of a hospital, he decides to investigate Sanagi's identity and his relationship with Miharu for the sake of his best friend Mishima.

With the Sports Festival coming up, Mishima and Honda's classmates have high expectations for them as members of athletic clubs.

After participating in the three-legged race with Mami, Honda believes they've grown closer. However, things don't go well when he asks her out on a date.