In Japan's Warring States period, Lord Daigo Kagemitsu makes a pact with 12 demons, offering them his unborn son in exchange for the prosperity of his lands. Years later, young thief Dororo is attacked by a ghoul but rescued by a mysterious boy, whose body parts turn out to be almost entirely prosthetic.

Kagemitsu, who offered up his own son to the demons. Hyakkimaru, who is trying to get back the body parts that were taken from him. As if drawn together by fate, they face each other.