Shinichi has a wife and children, but he was conscious of his mother as the opposite sex ... I know it's no good, but I couldn't suppress my overflowing libido. And one day, if in a place that is not home. The two lie to each other's families and visit on a hot spring trip. Because I know it's no good, my liberated desires explode. But I can't hold it back anymore ... At first, I was confused by the insertion of a phallus for the first time in several years, but I forgot myself and surrendered myself to pleasure ...