I decided to visit my parents' home with my wife. Toshiko, my divorced mother-in-law living alone, is well-endowed, has a great figure, and is too beautiful to be called 'mother'. However, I found out various things: her affair with a married man, her indulging in masturbation in the bathroom. As we were alone by chance, I decided to take advantage of this situation and made a move on her, but it ended in failure as my wife came home. Now, I can no longer control myself with reason, so I'm waiting for my wife to fall asleep to carry out my nocturnal intentions...