Touka is asked by her cousin to take care of her nephew, Yoichi. Touka comes from a single-parent household and readily accepts, thinking it would be perfect for her son to have someone to play with, but Yoichi is attracted to Touka's beautiful body and approaches her when her son isn't looking. "They're so nice... Touka's big boobs..." Yoichi has always envied Touka's exquisite body, and he relentlessly pampers her as if she were his own son, stimulating Touka's sexually frustrated body. Their relationship quickly develops, and they end up having sex behind her son's back...