One night, while her son's friend was staying over to study, Ryoko Nagase was unaware that he had been secretly watching her. By chance, he witnessed her masturbating—a shocking sight that ignited his desire. Feigning illness to stay behind alone with her, he took bold action. Though Ryoko initially resisted his forceful advances, she gradually succumbed to his passion, surrendering her body to his lewd caresses. That night's events would become a major turning point in her life.