When he woke up, he was in a room he didn't know.
The only light in that room was the moonlight coming from the window.
When he raised the upper part of his body, the body creaked as if he had been bedridden for a long time.
He didn't know what place it was.
He didn't know who he was.
He couldn't remember his name.
When, bearing the pain, he descended from the bed, the dust, thinly piled up, was whirled up.
When he went outside, that place looked like a section of a castle somewhere.
But nearby there was nobody and at the windows there weren't lights.
Only, in the far zenith, the full moon was shining.
Suddenly a restless chill took possession of him.
The world was softly distorted, the sound of a bell reaching him from far behind resounded in his head.
How much time had passed? The chill and the sound of the bell had already gone away.
To take their place, in front of his eyes there was someone's shadow.
But ... it had something fantastic.
[Translated from Official Page]
Chaos Labyrinth is an old-school dungeon crawler, which also means that it’s a grindfest. The monsters are actually girls from your school and defeating them (and having sex with them) reveals their past. You need to defeat the same girl many times in order to temporarily turn her back to normal, although that requires you to return to the start point and lose all skills you had accrued to that point. You also can’t have more than one girl back to normal at any given time.
[From Hau~ Omochikaeri!]