Nanami has been married for a year to the older man she met at work, but their unsuccessful attempts to conceive are making her anxious. The pressure has also left her husband struggling to get hard. One night, she feels the man who has apparently come home and discovers that his cock is erect. Determined not to waste the opportunity, she immediately starts sucking him. But the voice gasping, “I’m gonna cum!” belongs not to her husband, but to Kinoshita, his subordinate who is staying over. Afterward, Kinoshita keeps approaching Nanami whenever her husband is away. Unable to forget the taste of the cock she sucked that night, Nanami gives in, and the two sink deeper into an affair.