Hibiki and Naoya are step-parents. Hibiki tries to be a good mother, but Naoya is a marriageable man. There is no way he won't see the young and beautiful Hibiki as a woman. The fruitless days of endurance weakened Naoya. Feeling he has reached his limit, he decides to leave home. Finally, the three of them go on a trip to a hot spring, which was supposed to be a time when he would be able to cut off his feelings for Hibiki once and for all...