Nanako was in a good mood as they went on a trip together as a family and went to a hot spring for the first time in a long while, leading her husband by the arm to the inn. - Everyone would think that they are a close family, but in reality, mother and son had a secret that the husband did not know about. - I don't know when, but by the time Nanako noticed her son, they had been in a loving relationship many times. - Relax in the hot springs and enjoy delicious food and drinks. - When her husband got drunk and fell asleep, Nanako's face changed from that of a mother to that of a woman. - Mother and son looking at each other. - They were completely in heat and silently devoured each other. - She reached climax many times, taking the essence of her beloved son deep inside her, and passionately kissing her like a lover. - Little did they know that this secret relationship was being seen by someone...