Members of Kanna's university dance circle got together for the first time in a few years to celebrate the engagement of Kanna and Masao. Suspicion arises that Kanna and another member had sex, leading to fights and arguments between friends.
Suzuki Koichi, a 30-something hikikomori shut-in, allows his mother to dotingly tend to his needs. When she discovers that Koichi has killed himself, the shock is so great she loses consciousness and her memory of that day.