The old robot gets stolen, the hero gets buried, and everything you thought was unbeatable turns into a coffin. Then Kouji shows up in something bigger and meaner, and every punch he throws is revenge made metal. Mazinkaiser exists to erase a loss so complete that the only answer is overwhelming force.

Kouji Kabuto and his allies face their darkest hour when Dr. Hell's forces overwhelm them in a devastating assault. Mazinger Z falls into enemy hands, and Kouji disappears in the fighting. Baron Ashura turns the stolen robot against the team, and Tetsuya Tsurugi is left to hold the line in the badly damaged Great Mazinger. Then Kouji returns at the controls of Mazinkaiser, a new Mazinger with thicker armor and more lethal attacks. Seven episodes of mecha action and science fiction follow the fight against Dr. Hell's mechanical army.