In Muromachi period Japan, an Emishi village is attacked by a demon. The last Emishi prince, Ashitaka, manages to kill the demon before it reaches the village, but not before its corruption curses his right arm. The curse gives him superhuman fighting ability, but will eventually kill him. The demon is revealed to be a boar god, Nago, corrupted by an iron ball lodged in his body. The village’s wise woman (Oracle in the original dub) tells Ashitaka that he may find a cure in the western lands Nago came from under exile.