Ayako Inoue, a married woman suffering from a sexless marriage with her ordinary husband, secretly relieves her desires by masturbating every night after he falls asleep. One day, she discovers a blog titled "Female Body Training," where women undergo intense sexual discipline. Fascinated and deeply aroused by the scenes of women being trained, she can no longer suppress her excitement and emails the blog administrator with a single message: "Please train me." The appointed day arrives. Ayako is bound, beaten, and tormented. The pain and pleasure awaken her inner masochist, crushing her under the euphoria of humiliation and transforming her into a helpless sex slave.