The case was closed after 52 hours. During that time, 12 people died in total. Human beings became beasts in the inescapable classrooms. Twenty-seven former sixth-grade members of Shinozuka Elementary School, who gathered at their ex-school building for a reunion, were imprisoned. The name of the culprit was the school's alumni, Mikio Yumesaki. The experiment on "human virtue under extreme circumstances" revealed the true nature of human beings. Suspicion, lust, revelation, revenge, and betrayal. Ethical suspense that denounces morality.