Hinako, whose sickly sister asked her to have 'sex for making a child' with her brother-in-law (the husband of the sister), feels the lecherous gaze from her brother-in-law every day and is confused. However, she decides to accept the request for her sister's sake. But contrary to the desperate thoughts of the sisters, the brother-in-law becomes engrossed in sex with Hinako, forgetting all about making a child. And Hinako also gradually changes both physically and mentally…
