Captain Danger has built two gigantic dinosaur robots in his undersea base and launches an attack on Dr. Brilliant's laboratory while Gigantor is being repaired. Could this be the end?
Mr. Skee Matic kidnaps Jimmy and takes him to his secret headquarters where he shows him his robot collection - the largest in the world. Among them, his newest acquisition, Gigantor!
The evil Scrag and his henchman Sleek have been building a top secret weapon that uses a Tesla coil to generate lightning - just what they need to get rid of Gigantor for good!
Dr. Nutzen Boltz convinces Brainy, the robot with a dialectronic brain, to let him study his brain. In exchange, he will build a robot for Brainy that can destroy Gigantor!
Professor Stinger is back and this time he's got Big Fang's robot brother Irontron, who's been built for one purpose only - to defeat Gigantor and jimmy Sparks once and for all!
When scientists from the Atomic Factory are kidnapped by a giant whale, Gigantor dives into the sea to see what's going down. But the whale is actually a robot submarine form an undersea city!
No country will buy oil from poor Morabia. Rebels from neighboring Togaland have frightened all the customers away by setting oil fires. Can Gigantor take the heat and make everything cool again?
As Skull Duggery Prison, Goldy Brix is locked up with the monster Big Fang. Big Mistake. They break loose and with help from Professor Stinger's String Ray robots, they can't be stopped.
Escaped convict Goldy Brix is attacking luxury liners from his underwater base and using his own giant robot, Blastro. When Blastro disables Gigantor, it's anybody's game!
Gigantor is sent deep into the ocean to search for a sunken island and buried treasure. Instead, he finds the evil Thermal Updraft, whose hideout is guarded by the unbeatable Albatross robot!
A robot factory run by a man named Crank unleashes Magnaman, a super robot who's been programmed to destroy all of man's masterpieces, starting with the Eiffel Tower!
As a reward for rescuing him from the fires of a volcano, a powerful Firebird makes Swami Rivers the most powerful man on Earth. Now only Gigantor can put out his fire.
General Shark has a new secret weapon - termites that eat steel and concrete. Now, no city is safe from a Shark attack. Can Gigantor exterminate the growing problem?
Dr. Buzz Bugaboo is kidnapped by Brany Mantis and forced to turn over his formula for making huge insects. The big bugs are then unleashed on the city, in number too gigantic for even Gigantor to stop.
General Ising Nutcake of Beanie plans to take over the world. Using his Wave Image Maker, he take Gigantor, Jimmy and the Inspector prisoner. Can anything stop him now?
Magnaman is back and he's under the control of Muggs Muggler and his gang, who know his secret code. Only Gigantor can stop them now, but it'll be robot against robot in a duel to the finish.