Airi, who modestly lives in an apartment complex with her doctor husband, one day witnesses her husband having an affair. - Next to my husband is a married woman who lives in the same housing complex...Yes, my husband was having an affair with another married woman. - She consults the other party's husband, Tanaka, but he doesn't believe her, so they decide to watch the moment of the affair. - The two, hurt by witnessing a decisive moment, grow closer together to make up for their loneliness. - Unsatisfied with their life partners, the two begin an affair in which they seek each other out...