Wataru Ikusabe, a fourth grader, is taken by a guardian dragon that appears from a pond called Ryujin-ike (Dragon God Pond) to the world of the gods called "Shinbukai". At the center of this world is the mountain of the gods, Mount Sohkai, where the evil emperor "Doakdar" suddenly appears and rules over the gods and Mount Sohkai. Together with Ryujinmaru, who has become a real "Mashin" he sets out to defeat Doakudar in order to restore the seven rainbows that Mount Sohkai.