A close friend of Satou's mother from her student days, Natsuko-san, came to stay at the Satou household. Their son, Satoru, was drawn in by Natsuko's adult charm. When she found out that Satoru was still a virgin, Natsuko said, 'I'll be your first woman,' and gently guided him. Despite his tension and confusion, Satoru successfully graduated from being a virgin and, like a newly trained monkey, kept desiring Natsuko...
