Nao, a beautiful wife who is struggling with her nightless life, witnesses her husband having a single sexual intercourse. When she finds out that her husband, who has not had her for six months, is not incapable, she loses her confidence as a woman and at the same time, her sexual desire. One afternoon, while rubbing her crotch alone, she looks up to see her middle-aged neighbor, Shirai, who has come to greet her moving in, and their eyes meet through the window. The two were never meant to be together, but witnessing this masturbation led to an affair that later became so intense that it made her sweat...
