Yuu, a married woman, was recommended to join a tennis club by a mommy friend to help her get some exercise, but she ends up becoming friends with the younger coach. A married woman with too much free time and sexual desire doesn't need any troublesome maneuvering, and she easily invites the coach over to her house and they become physically involved. Of course, such a sweet relationship doesn't end with just one time, and the next day, Yuu invites the coach over again in broad daylight, unbeknownst to her husband, and they become indulgently involved in a physical relationship. She has no idea that the manager is watching them...