Manaka, a devoted student at Seihou Girls' Academy, is deeply in love with her teacher, Tonami-sensei, and is willing to do anything to maintain their relationship. However, her trust is shattered when Tonami betrays her, forcing her to provide sexual services to a group of his acquaintances in exchange for money. Trapped by her love and the teacher's manipulation, Manaka endures a harrowing ordeal, only to realize that she is being used as a tool for her teacher's financial gain.
After a scandalous video of her younger sister Manaka surfaces, Student Council President Mizuki is blackmailed by the predatory teacher Tanabe. To protect her sister's reputation, Mizuki reluctantly agrees to a sexual arrangement, falling victim to Tanabe's manipulation and cruelty.
After three days of coercion, Mizuki is led to a secret den where she discovers a network of students engaged in prostitution orchestrated by Mr. Tanami. There, she finds her sister Manaka, who has already been corrupted by drugs and pleasure. Though Mizuki initially tries to rescue her, she eventually succumbs to the aphrodisiacs and the men, leading the two sisters to bond through a shared descent into hedonism.