Mitsuki Nagisa is a pure woman who has never experienced vaginal orgasm before. By giving her an aphrodisiac said to intensify sexual desire, her body gradually begins to change. She is confined in various enclosed spaces—bathrooms, closets, wardrobes—each one dark, narrow, and suffocating, amplifying her fear and heightening her sensitivity even further. As her claustrophobia intensifies, her rational mind begins to break down, drawing her into dangerous pleasure. In the end, she reaches an extreme climax, screaming, losing control, and convulsing in an overwhelming ecstasy.