Rio initially welcomes her adult brother-in-law Yuta when he moves in while job hunting. Secretly obsessed with her, he steals through her underwear and spies on the married couple having sex. She senses his lustful gaze but pretends not to notice until desire drives him to attack. His merciless pounding gives Rio orgasms her husband never could, and the pleasure hammering deep inside gradually conquers her heart as he keeps creampieing her with the goal of pregnancy.