Kenta Tachibana, the protagonist, was a swimmer with great hope for the future during highschool. But at one point, he suffered a serious injury protecting a strange child from a runaway car, and was forced to retire. One year later, Kenta finished the rehabilitation and decided to work in a certain sports club as a coach. Kenta is the hope of the people who say that recovery is hopeless, and do not want to stop swimming. In the first day of attendance, he is stunned that his appointed destination is a sport club full of women. The only female manager in the club that is operated by relaxation facilities and extensive a reputation for a reasonable fee, where he had become a place of recreation and relaxation of our Neighbor's Wives . It have been known to the people in the health club the coach is also a swimmer. But human health is not immune to the curious eyes of our uninhibited married woman ... even just pierce. Kenta managed to finish the first day at work, and was floating in the pool, when someone has jumped into the pool too. It was his older sister figure he was separated for 10 years, Ai Narushima.