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.
Summer vacation is over, and the Aozora Cultural Festival is approaching. After things went well with Mami at the fireworks display, Honda is delighted to be spending more time with her preparing for the festival.
Mishima worries about Miharu's absence from the cultural festival. Mishima's class encourages Nakajima's childhood friend Sasaki Waka to run in the student council elections.
Honda and Mami are steadily growing closer, but they both have concerns about their families. Honda is having trouble with his relationship with his mother, and Mami remains unable to tell her family about her relationship with Honda.
Honda and Mami seemed to return each others feelings, but their concerns push them apart. Worried about the couple, Mishima and Miharu put aside their own relationship to discuss if there's anything that can be done for them.
Mishima has been unable to focus during swim practice since the new semester started. Though his relationship with Miharu has returned to normal, he still feels as though something is lacking. Meanwhile, Miharu begins missing school for some reason.
Mishima has been concerned since Miharu went to the hospital and visits her every day. Honda and Mami are naturally worried about Miharu as well, but they're also concerned about Mishima.
Miharu is scheduled to take time off from school and transfer to another hospital for surgery. She feels both anxious about the upcoming procedure and sad to be moving away from her friends.
