Kanako is married to a man much older than her. He has a child named Kazuo, who is close to her age. They have a happy married life, but their sex life is not so good due to her husband's age. Whenever they try to have sex, her husband always falls asleep first, and Kanako, who is in the prime of her life, is frustrated. As she spends her days in frustration, Kanako sets her sights on Kazuo. She invites him in by offering to wash her back in the bath, but...