在不远的将来，世界各地均出现了通往[void]的传送门。无数怪物穿越传送门之后开始肆意地破坏。
人类为了获得安全而在周边建立村庄。通过操纵怪物的DNA[赤目]生产出了生化人，用来抵挡怪物们的进攻。

20年时光流逝之后休眠中的[void]再次扩大。主人公凛背负起拯救人类的重担，开始调查背后的根原

In the near future, a portal to [void] has opened somewhere in the world. Monsters are crawling out of the portal and rampaging. Humans have built [villages] around the radius of [void] to keep them safe. Humans also used the monster's gene, the [red eye], to create cyborgs and thwart monster attacks.

And 20 years have passed. The dormant [void] suddenly started to expand again. Our protagonist, Rin, needs to investigate the reasons behind her and save humanity from extinction.