The following details are from an XSEED Games press release:

In Corpse Party, players take control of a group of Japanese high school students who inadvertently engage in a pagan ritual and find themselves inexplicably transported into a whole other space: an inescapable echo of a long-since demolished school building where a series of gruesome murders once took place. They must now evade the grasp of the tortured souls who roam the halls of the doomed Heavenly Host Elementary School, lest they join the ranks of the dead themselves.