The story is set in Heavenly Host Elementary School, an elementary school that was torn down following the murders and disappearances of several of its staff and students. By the start of the story, another school called Kisaragi Academy has been built over the elementary school site. One night, a group of students from Kisaragi are telling ghost stories when a sudden earthquake transports them to another dimension where Heavenly Host Elementary still exists and is haunted by the ghosts of the school's murdered children. The students of Kisaragi Academy students try to find their way home and survive the other mysterious forces that haunt the school.

[Source: Wikipedia; emended]