After his parents leave for an overseas trip, Ryo moves in with his aunt, Nakanoue Ayai (Chisato Shoda), and her husband. Drawn by lewd moans seeping from their bedroom, Ryo begins secretly watching his aunt and uncle having sex. Though anxious about being caught, he finds Ayai acting as if deliberately tempting him with bold, provocative behavior. From that night on, the image of her lustful figure is burned into Ryo's mind. As Ayai continues to seduce him with gentle yet aggressive advances, he gradually succumbs to her irresistible allure.