A warlord named Daigokagemitsu makes a deal with forty-eight demons and promises to offer his unborn child in exchange for realizing his ambition to conquer the country. Later on his son is born with unbearable fate.

A mysterious young samurai named Hyakkimaru is traveling alone, slaying monsters along his way. One day he encounters a thief named Dororo who follows him, trying to steal his sword.