Six months ago, one night, Yasuhiro accidentally witnessed his mother masturbating. Ever since that night, he has secretly watched from the shadows as his mother opens her legs every evening. As he observes her going about her daily chores, the son gradually begins to develop sexual feelings toward her. With age, the mother's libido grows stronger, and unable to suppress her desires any longer, she begins pleasuring herself while whispering her own name. The sensual curves of her mature body leave her son breathing heavily, his heart pounding more intensely than ever before.