Since losing her husband, Emi has raised her son Mitsuo on her own.However, now that Mitsuo is finally becoming a full-fledged man, Emi is both happy and a little worried.While she's tried her best to be her mother, all these years she's forgotten that she's a woman...Ever since she realized this, Emi felt her sudden thirst in her body and began to comfort herself on a daily basis.However, the sight of her single-mindedly indulging in masturbation in her dark room drives Mitsuo, who thinks of her mother, to take unexpected actions.