In Japan's Warring States period, Lord Daigo Kagemitsu makes a pact with 12 demons, exchanging his unborn son for the prosperity of his lands. The child is born malformed and is set adrift in a river, while Kagemitsu's lands thrive as promised. Years later, young thief Dororo encounters the mysterious "Hyakkimaru", a boy whose arms are blades and whose visionless eyes seem able to see monsters.