The Mazinger Z is on the brink of defeat but the Great Mazinger arrived in time to help. The Great, its pilot Tetsuya Tsurugi, and Tetsuya's partner Jun Hono fight against the Mycenae Empire. The Empire however, manages to make deals with the governments of Earth in the battle making it a difficult battle where no one is safe. Eventually the Great General of Darkness fights against the Great Mazinger and after a long battle, the Great manages to win. However, the Emperor of Darkness had resurrected Dr. Hell as the Great Marshall of Hell who leads the attack on the Great Mazinger, eventually claiming the lives of Kenzo Kabuto and Misato. In the final battle, Tetsuya manages to destroy the Great Marshall at the cost of the Great and his life.
Differences from other mediaEdit
- In a few scenes Tetsuya joined the Self-Defense force to fight the Mycenae Empire in a secret mountain base before being ridiculed by the higher ups, which was later revealed to be because the government made a deal with the Empire.
- Going deeper into the hidden alliance with the Empire, the Great Mazinger's blueprints and materials were stolen from the Science Fortress Lab to try and mass-produce the robot and sell them to other countries for national profit. The Defense ministry's daughter managed to convince her father out of the operation through her actions and the ones who attempted to carry out the operations were arrested in spite of a possible Great Depression.
- Much like the anime movies being included in Ōta's Mazinger Z, the events of Great Mazinger vs. Getter Robo are included but not the sequel Great Mazinger vs. Getter Robo G: Kuchu Daigekitotsu.
- By the time Great Marshall of Hell is introduced, he has the Japanese government attempt to hunt down the Great after threatening to poison Japan's cities with sludge emissions. As a result of the Science Fortress Lab is destroyed when they refused to turn over the Great. Dr. Kabuto had managed to escape, but the nomadic groups are on the lamb where even with help from a Self-Defence member proved to be useless and the once great cities of Japan are turning lawless.
- Misato is killed by Marquis Janus after escaping the Science Fortress Lab.
- Great Marshall of Hell had space weapons such as an ice lense that would magnify the satellite weaponry. Dr. Kabuto had managed to make a deal with the United States government to help fight against the space weaponry with NASA's resources. With the Great and Venus dealing with threats in Libya they gain the authorization using decoys and nuclear weaponry to take out the Empire's forces and the Ice Lense.
- With Dr. Kabuto's sacrifice, Tetsuya goes to the Empire's headquarters alone to have the Great blow it and the Great Marshall up, at the cost of Tetsuya's life.