Young Duke Ernest wants to become a good knight. The circumstances are not in his favour: The emperor wants to claim the Duke's castle and marry his mother. He has Ernest wrongfully accused of murder and thrown in the dungeon. Duke Ernest's only chance to escape a death sentence is to join the army and to go to the orient in search of the legendary Carbuncle Stone. He'll have to overcome carnivorous rocks, magnetic mountains, the giant bird Rock and many more.