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...