This work, adapted from the manga by Yae Utsumi, is a suspense film about a brutal 52-hour class reunion that changes the face of life. 23 people from the former 6th grade 2 class who gathered at their alma mater for a class reunion were imprisoned by their classmate Mikio Yumesaki, and 13 of them died. Mikio's goal was to "test how long a person's 'goodness' can last under the extreme state of life crisis." In the gradually chaotic order, revenge, bullying, betrayal, and revelations unfolded among the former classmates.