At a boarding school with no sports festival and only cultural clubs, Arata, a new student, leads a rather ordinary school life.

Every morning, he's woken up by the guy sitting next to him, his frenemy, a male friend, the class representative, and a teacher who's a bit too free-spirited for his role as homeroom teacher.

While it sounds peaceful, Arata also feels a sense of restlessness in these uneventful days.

Then, a transfer student arrives out of season, shaking things up.

As the big event, the cultural festival, approaches, Arata and his classmates look forward to their last youthful hurrah, but a strange illness begins to spread throughout the school...