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.
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.