Miho gave birth and got married at a young age, but gradually became sexless, and her husband's affair was discovered when her son became a college student. While she was separated from her husband on the premise of divorce, her son came home for summer vacation. A son who confesses that he liked his mother on a hot spring trip with his son to report his divorce. - She is touched by the kindness of her son rather than her heartless husband, and although she thinks that it is wrong, her sense of immorality as a mother and her joy as a woman collide. In a small inn deep in the mountains, parents and children forget themselves and mingle ... A mother-child incest story!