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

Summer vacation is over, and the Aozora Cultural Festival is approaching; after things went well with Mami at the fireworks display, Towa is delighted to be spending more time with her preparing for the festival.

Haruki has been unable to focus during swim practcse since the new semester started; though his relationship with Miharu has returned to normal, he still feels as though something is lacking; Miharu begins missing school for some reason.