In order to secure his campaign across Japan, the merciless warlord Daigo Kagemitsu proposes that he will offer his unborn son to 48 demons. The demons agree, and the following day the infant arrives with several missing limbs and is mercilessly thrown into a river.
Fifteen years later, a defiant youth named Dororo struggles to survive amid hunger and the tyranny of samurai in a poverty‑stricken, war‑ravaged hamlet. After provoking a gang of roughs, Dororo is assaulted by them, but a shadowy figure steps in, claiming to sense spirits nearby. A monster indeed erupts from the water, and the stranger removes his prosthetic arms to reveal concealed blades, cutting down the beast before vanishing.
That evening, as the stranger wanders through the woods, Dororo follows and vows to stay with him. The man—Hyakkimaru—confesses that demons have taken most of his body parts and, despite hoping for a quiet existence, he cannot escape their relentless pursuit. Yet Dororo remains determined to accompany him. Thus Hyakkimaru journeys across Japan with his new ally and a pup named Nota, confronting the savagery of both inferno and humanity.