Yumi and her husband met at work and have been married for years. One day they help their close coworker Yoshimura move. Still single despite repeated advice to find a girlfriend, Yoshimura instead boasts that he is having an affair with a married woman. Her husband dismisses it as another empty brag until Yoshimura calls him to a house to show him proof. Through a magic mirror, he is confronted with the devastating sight of his own wife having sex with his coworker.