Koichi Takahashi, an AV director who calls himself the ``lover of a married woman's heart,'' lets his wife's female friend stay at his house with ulterior motives. There's no reason why a married woman who spends the night alone with herself has nothing... Kumiko is 2 years old, has been married for 35 years, has no children, and works as a helper at the family's udon restaurant. The house owner, who was supposed to be absent, returned and the married woman, who was in a hurry, had dinner with him and was in a relaxed state, confessing her worries that she was unattractive as a woman. The insecure married woman is encouraged by her director and decides to take a lecture on how to bond with her husband. She accepts the instruction that gradually becomes more extreme, and with a little secret, she is allowed to have her genitals groped and penetrated by a penis. He cums every time he changes her position, and cums immediately from behind her back. She wakes up and gives him a blow job in return for having been made to cum by playing with toys in the middle of the night. Even during morning sex, she obscenely twists her hips and faints in agony.