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.

(Source: Anime News Network)