After a crushing defeat by Dr. Hell where Mazinger Z is stolen, its pilot Kouji Kabuto returns with the more powerful Mazinkaiser to battle Dr. Hell's forces and Baron Ashura, who wields the stolen Mazinger Z.

In one of their epic battles, the Mazinger Team suffers a crushing defeat at the hands of Dr. Hell and his minions after Mazinger Z is stolen and its pilot, the legendary Kouji Kabuto, is rendered missing in action. Just when Dr. Hell's second-in-command Baron Ashura uses Mazinger Z against our heroes, Kouji makes a surprise return in Mazinkaiser - an all-new Mazinger with heavier armor and deadlier attacks.—Gavin Nelson