Yuu, a married woman, is frustrated by her husband who masturbates in secret without making love to her. She has no choice but to masturbate herself, but her neighbor Misawa sees her through a window he forgot to close. Misawa apologises desperately, saying he meant no harm, and Yuu senses his sincerity and decides to talk to him about her dissatisfaction with her husband. As they start talking about sex, Yuu feels a change in her crotch. The two, who were never meant to have sex, end up in an affair so intense that they end up sweating after Misawa witnesses her masturbating...