Shiori, whose husband is constantly on business trips and cannot be taken care of. Despite having just remarried, her dissatisfaction has reached its limit. Ryuya, Shiori's stepson, sends her a passionate gaze. He confesses that he has always liked Shiori. However, no matter how dissatisfied, a parent-child relationship cannot have sex. Shiori tries to soothe Ryuya, but in his excitement, he pushes her down. His strong thrusts continue until Shiori orgasms and her voice breaks... .