In the aftermath of a strange earthquake, an entire elementary school vanishes, leaving nothing but a hole in the ground. While parents mourn and authorities investigate, the students and teachers of find themselves somewhere far away?somewhere cold and dark... a lifeless, nightmarish wasteland among which their school stands like a lone fortress. As panic turns to terror, as the rules start to fall apart, a 6th-grade boy named Sho and his friends must try to survive in a hostile new world...