Mayuko, who lives with her husband and father-in-law, has a problem. While her husband is at work, her father-in-law, who has retired and has a lot of free time on his hands, relentlessly sexually harasses her. Not wanting to cause trouble for her husband, Mayuko even allows him to have sex with her just once. However, since then, she has been unable to forget the pleasure her father-in-law gave her...