This is the sequel to Mashin Eiyuden Wataru first season. 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 7 Stars Mountain, the source of Mt. Soukai's rainbow, have been taken over by Doakadar (Doakudar'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. (myanimelist.net)