Mai and her husband have been married for a while. When they first got married, her husband would make love to her every day, but the frequency gradually decreased over time. It has been three months now since she has not been touched, feeling uncomfortable and restless, causing her to engage in extremely inappropriate behavior. Whenever her husband is not around, she wears see-through outfits, clearly revealing her lingerie underneath. Each time she does this, her neighbor Yuzuru cannot take his eyes off her body. Knowing that her neighbor is attracted to her body, combined with the lack of sexual satisfaction, Mai wants to forget everything. On the occasion that Yuzuru accidentally dropped his keys and had to wait for a repairman, Mai waved him in and let him have sex with her freely. And their inappropriate relationship started from there. Whenever her husband goes to work, she lets Yuzuru have sex with her, almost every day they engage in sexual activities. They become more and more daring, with Mai even allowing Yuzuru to have sex with her knowing that her husband may be returning soon...