After a childhood friend's suicide, Hideaki and his former classmates reunite to pay their respects. Soon after, a DVD, marked X arrives revealing a man being tortured, triggering a flashback in Hideaki, reminding him of witnessing a schoolmate being subjected to humiliating batsu (punishment) games. One evening, Hideaki is kidnapped and when he awakens the next day, he discovers he is in a recreation of his old school-room, along with his fellow classmates. Trapped and held captive by mysterious hooded figures, each of them must now play a brutally violent, version of the punishment game, in order to survive.