Torn to pieces by a pack of dogs, young samurai Jintetsu's ravaged body has been found by Genkichi, outcast and master inventor. Genkichi gives the dead boy a new, indestructible steel body and a talking sword - just what he'll need to exact his vengeance. But what about Otsuki, the beautiful girl he left behind? Steel armor is defense against any sword, but it can't save Jintetsu from the pain in his heart.