Serious and reserved teacher Kiho Kanematsu had always lived a quiet life, showing no interest in masturbation. But one day, during her commute, she suddenly experienced a molester's touch on the train. The overwhelming pleasure from being touched, combined with the tension of being unable to cry out, awakened deep-seated, uncontrollable desires buried within her. The innocent teacher she presents before her students stands in stark contrast to the shameful urges she wishes to hide, and gradually, Kiho transforms into a lustful woman eagerly anticipating daily molestation on the train. As her pride as an educator clashes with immoral desires, she can no longer lie to herself about her feelings. Each time she encounters the molester in public, irresistible pleasure and impulses take complete control of her mind, leading her to realize, "I can't lie to myself anymore." With every surge of pleasure, she deeply yearns, "I want him to touch me," "I want to be fucked by that man whose name I don't even know." Forgetting her role as a teacher and surrendering to her impulses, she loses herself completely—culminating in the confession, "I'm sorry... I'm a failure as a teacher..."—a statement that symbolizes her ultimate transformation into a depraved woman.