Full-time housewife Momoka Sawaki has recently felt lonely due to her husband's frequent night shifts, leaving her to spend many nights alone. One evening, her only son spoke to her with unusual kindness, gently soothing her aching heart. While she had grown accustomed to relieving her loneliness through masturbation during her husband's absence, that night she found herself thinking of her son's face while pleasuring herself—and could no longer resist sneaking into his room. She had only wanted to see his sleeping face, but the moment her hand accidentally brushed against his crotch, her restraint shattered completely. That night marked a turning point, as she was overcome by unfamiliar emotions and discovered a new, forbidden intimacy with her son.