On the last day of school just before summer vacation, a strange letter arrived for high school student Aito Eyama, in despair for being unfairly bullied everyday. It was an invitation to a "prison game" where anyone could confine anyone they want for a month. During that month, the Player is allowed to do anything other than kill their Partner, and if the Player's name isn't revealed, the Players can get a large sum of money. (Source: Coolmic)