First year student of the private Tsukioka School, Kusaka Hyoma, heard from his grandfather the legend of "when the gate to the alternative world opens, an incredible green glow can be seen, and the ancestors of the Kusaka family will step on this land". Although he did not believe in this, he was surrounded by unexplainable light when exploring the hill behind the school and found a cave. Thus, the prologue to an unknown adventure begins.
