Koji Kaboto tries his OVT that he made with pieces of mecano. When flying, he is attacked by the UFOs of Vega. Fortunately Duke Fleed arrives on time to save the day (but not too quickly nonetheless). Koji does not actually know that Duke Fleed is the prince of Fleed.
Koji discovers the identity of the Duke Fleed, but has no time to ask questions because Vega attacks. Duke Fleed and Koji unite their power and push back the enemy.
Gandal wants to discover the hiding place of Grendizer. So he launches a massive attack. Koji tries to confront the enemies alone, but he only succeeds to crush himself on a deserted island. Finally Duke Fleed makes it there and saves the day.
Blaki sets a trap to Grendizer by hiding mines in a cloud of spatial dust. Koji falls in the trap. Fortunately Duke Fleed helps him and destroys the Golgoth 8.
The Vegans plan is to bring Grendizer to the shadow of the moon during the eclipse because Grendizer's systems will shut down temporarily under it and then destroy it.
Daisuke and Kogi are sent to investigate an avalanche and to find survivors. They find a girl named Mirana who lost her memory. Back at Space Science Centre she begins to remember how a saucer destroyed her home.
A new Vegan mecha comes to destroy Earth. It sucks power from the sun and burns everything in its path. Grendizer is damaged by it and has to withdraw. As the mecha attacks again Grendizer has to go to battle weaponless.
Boss, Nuké, and Mocha are in this episode. They are visiting their old friend Koji Kabuto. The Vegans keep their eye on a mysterious orange robot that is found skiing near-by. Commander Blacki orders the Minifo to follow it and investigate.
The Vegans begin building a base for their operations on Earth. The saucer "Giba Giba" begins to attack but Grendizer comes to save the day by saving a town and a mountain.
Dr. Umon made a project so that Grendizer is able to launch without revealing his whereabouts to the enemy. Kabuto is control by the Vegans and fights Duke.
A huge meteor is headed straight gives order to fire on the meteor and change its course to head for the planet Earth. The meteors are detected and Grendizer launches to intercept them before they hit land.
Daisuke gets the suspicion that the Vegans may be planning to pull the moon down to Earth. Duke Freed launches Grendizer and follows Koji who already went to explore the area of Mount Kirofoki.