My wife, Tsumugi, has been married to me for several years now. As always, she lovingly prepares my lunch today. We share a happy marriage, just like when we were newlyweds. While standing before her, my immature coworker Hazuki boasts that women in their third to fifth year of marriage are easiest to seduce. Inspired by his words, I impulsively suggest he try flirting with my wife. Later, I invite him over under the pretext of watching a movie, leaving us alone together for three hours. When they both return home, they insist nothing happened between them. Despite their reassurances, I can't help but feel suspicious...

つむぎとは結婚して数年。今日も変わらず俺の為につむぎは愛妻弁当を作ってくれる。新婚の時と変わらず幸せな関係、そんな幸せな日々を送る俺を前にして『結婚3～5年目の人妻が一番落としやすい』と豪語する後輩の日森に、つい妻を口説いてみろと口走ってしまった…。自宅に日森を招き理由をつけて3時間、妻と2人きりにした。時間が経ち、家に帰った俺だったが何も無かったと言う2人の言葉を俺は完全に信じてしまって…。