After several years of marriage, Hibiki has been working hard to be a ``good wife'' to her husband, but the distance between her and her husband has only grown wider, and she is worried about how she can return to her normal life. One day, Hibiki meets her friend's husband, Aoi, who lives nearby. As they talk about their problems, the two of them grow closer and commit infidelity for the first time in their lives. However, Hibiki doesn't know that the cost of her first affair after marriage will be huge...