Yuji, staying over at his friend's house, found himself captivated by his friend's mother, Sana, who was beautiful and alluring. For days, he couldn't help sneaking glances at her back and cleavage. One night, while heading to the bathroom, he heard strange noises coming from her bedroom and discovered Sana deeply engaged in masturbation. Yuji secretly recorded the scene on his phone, then the next day used the footage to blackmail her, forcing her into a compromising relationship.