Avenging his father's murder is a matter of honor for the young samurai Jintetsu. However, the killer turns out to be a corrupt government official, and the authorities are now determined to hunt Jintetsu down like an animal. There is only one problem: Jintetsu is already dead. Torn to pieces by a pack of dogs, Jintetsu's ravaged body is found by Genkichi, an outcast and master inventor. Genkichi gives the dead boy a new, indestructible steel body and a talking sword—just what he will need to face down the gang terrorizing his hometown and the mobster who ordered his father's hit. But what about Otsuki, the beautiful girl he left behind? Steel armor is defense against any sword, but it cannot save Jintetsu from the pain in his heart.