Before the start of the series, Kazuhiro got dumped by his girlfriend Kyouko, with whom he had plan to come to the famous Koibana Onsen Inn popular with couples. However, not wanting to cancel his reservation, he comes alone nonetheless. During his visit, he ends up falling for Nonoka, the second oldest of the three daughters operating the inn. From then on he starts working at the Koibana Onsen part-time.