Sakuta Azusagawa's little sister, Kaede, is wrapping up middle school and needs to make an important decision. The school counselor believes it is in Kaede's best interest to attend an online high school, given her history of being a shut-in and her crippling phobia of traditional classrooms. However, Kaede wishes to enroll in Minegahara High School, just like her brother, as she desperately hopes for a typical high school experience. She pleads with Sakuta; his girlfriend, Mai Sakurajima; and Mai's half-sister, Nodoka Toyohama, to help her study for the entrance exam—and they enthusiastically agree. But her envisioned high school life does not unfold as planned. With her unresolved trauma coming to a head, Kaede grapples with the conflict of determining what sort of future path she truly wants to embark upon.

[Written by MAL Rewrite]