Recently, Nobuo has begun harboring sexual feelings toward his mother, spending his days cooped up in his room even on his days off from work. The only one who notices his strange behavior is the owner of the place where he works part-time. Worried about Nobuo, the owner pays him a visit, and Kasumi gradually lets her guard down around him. From Nobuo's mannerisms and behavior, she realizes he has feelings for her. His words leave Nobuo flustered, and he suddenly lunges at the owner. Witnessing this scene by chance, Nobuo begins to confront his own emotions. One day, Kasumi discovers semen stains on her son's underwear, and starts questioning the strange glances she's sensed from Nobuo lately. Could he be masturbating while thinking of her? Overcome by the thought, Kasumi herself begins indulging in masturbation. Fully embracing this twisted affection, Kasumi resolves to surrender herself completely and becomes a woman before Nobuo's eyes.