It’s autumn at Shuuka Academy, a full-boarding private school. The first-years have finally adjusted to life at the school, the second-years are enjoying their time, while the third-years are reminiscing with graduation approaching. Itsuka is your average third-year student who likes soccer and hangs around with his close friends: twin osananajimis Asagao and Yuugao, fellow soccer club member and best friend Jun, partner-in-crime Kousuke, class president Kanade, and homeroom teacher Shiori. There’s nothing particularly special, but they happily enjoy each day. But then one day, their lives completely change. On their way home from a choral competition in which the whole class participated, they encounter an unknown group of people. And it is this encounter that completely distorts Itsuka and his friends' destinies. Itsuka and his friends' lives are drastically transformed, from a gentle ordinary life to a cold and bloody hell. It is a neverending nightmare woven entirely of despair and sadness. In this nightmare, Itsuka is gradually driven into a corner. The spirit of an ordinary boy continues to scream and wander about in search of salvation. However, the only things to be found are the sins and punishments that have seeped into Itsuka's hands. Salvation is nowhere to be found. Itsuka merely continues to walk the path of destruction, as the bonds and memories that he has created with so many people over such a long time are crushed to smithereens by his own hands.