You open your eyes after a hellish and terrifying nightmare, only to discover a crack in the dimension.

From that crack appears Ku'on, the little boy who used to play with you when you were a child.
Saying that he needs your help, Ku'on drags you into the crack.

The two of you get separated and soon you learn that you’ve arrived in a world where Oni exist.
Who will you encounter in that world…!