While some members of Kisaragi Academy's class 2-9 survived their trip to the hellish, otherworldly elementary school known as Heavenly Host, many did not... and those who were unfortunate enough to perish within its halls were doomed to remain there forever, eternally reliving the pain they felt at the exact moment of death. Worse still, all memories and records of their existence were wiped from the face of the earth, leaving only those who survived the ordeal to mourn their loss.

The last hope of reverting these miserable fates rested with an ancient tome known as the Book of Shadows, but Ayumi Shinozaki’s misguided attempts to employ its power claimed yet another victim, and the book was forever lost in the chaos.

...Or was it? When an acquaintance of the deceased turns up with a spiritual photograph suggesting the Book of Shadows may now reside in the tattered remains of Heavenly Host, Ayumi becomes obsessed with finding it so she can attempt once more to bring back her lost friends…