Sakurakawa Momoka is captured by a secret evil organization called Portion. Her comrades have sustained injuries from the its modified humen and were also captured. In order to find out about Momoka's organization and its power, a Portion's executive, Lady Violet, lined up monsters in front of the woman and said, "Fight with them. If you win, I shall release you together with your comrades. But if you lose..." Against the wickedly smiling Violet, Momoka resolved herself not to lose, even if she had to fight alone. However, it is not a fight that has started, but a wild party of ecstasy. The monsters have various powers to inflict pleasure, and so her reason has begun to gradually melt. What kind of end is waiting for her?..