Wataru has been lived happily on earth after he defeated Doakudar. When he plays around with his friend, Ryujinmaru appears and ask him to fight again. It appears that the Mt. Seikai, the source of Mt. Soukai's rainbow, have been taken over by Dowaruda (Doakuder's brother). If all the stars mountain loses their brightness, Mt. Soukai's rainbow will fade and everyone will live in the darkness for eternity. Once again, Wataru has to go through Mt. Sekai's seven mountains and destroy this new stronger enemy.