Kaho and Hiroshi are mother and son who have always been close. It is customary for the family to go on a hot spring trip every year. This year, the father is busy, so the mother and son go on a hot spring trip together. In the father's absence, the delicate relationship between mother and son becomes clear. Kaho is not on good terms with her husband. Kaho and Hiroshi also discover that they are aware of each other as the opposite sex. At first, Kaho refuses the relationship out of concern for public opinion, but eventually she accepts and the mother and son greedily seek each other...
