After an experiment on a strange meteor fragment, Reed Richards wants to take a rocket to the Blue Area of the Moon where it came from. Meanwhile in the Soviet Union, a Russian scientist named Ivan Kragoff completes his training of three apes who will pilot his own rocket mission to the moon. As the Fantastic Four are blasting off so is Kragoff and his apes. Seeking to duplicate the accident that gave the Fantastic Four their powers, Kragoff had designed his ship to be transparent so that he and his apes would be exposed to an even greater dose of cosmic rays.

Part 2: Menace on the Moon!
Although they are spotted by the passing Fantastic Four, Kragoff's attempt worked. Gifted with the power of intangibility, Kragoff rechristened himself the Red Ghost. While his now "Super-Apes" gained powers as well, Igor the baboon became a shape-shifter, Peotor the orangutan gained control of magnetism, while Miklho the gorilla gained enhanced strength. When the Fantastic Four finally land on the moon they discover the ruins of an ancient civilization on its mysterious "Blue Area" as well as a strange citadel off in the distance. The group then splits up to explore. While out searching, the Thing is attacked by the Red Ghost and his Super-Apes.

Part 3: The Watcher Appears!
However the fight is abruptly stopped by an alien calling himself the Watcher, who incapacitates the Super-Apes with his vast cosmic powers. The Watcher explains that his race of people have been charged with watching other alien races but have a vow to never interfere. Having come to consider the human race to be nothing more than savages fighting over their petty territorial disputes, the Watcher orders them not to bring their war to his home and dispatches the Fantastic Four, Red Ghost and his Super-Apes back to the ruined city where they could fight to the finish so that the Watcher could determine whom came from a superior country.

Part 4: Duel in the Dead City!
There the Red Ghost and his apes attack the Fantastic Four and take the Invisible Girl prisoner. Reed and the others then begin searching the ruins for her. Meanwhile, Sue realizes that the Red Ghost has control over the apes by withholding food from them. While the Red Ghost was out fighting her teammates, Sue freed herself by offering to give the Super-Apes food. Over powered the Red Ghost sought to seek refuge in the Watcher's citadel, only to be buffetted through time and dimensions before being ejected out. The Red Ghost was then incapacitated by Mr. Fantastic who was able to fashion a paralyzeation ray. With the Red Ghost defeated, the Watcher reappears before the Fantastic Four and congratulates them on their victory and tells them that their country is the superior one and so long as it strives for peace it will have a place in the limitless universe. As the Fantastic Four prepare to leave for Earth, the Red Ghost is freed by his Super-Apes, who have come to get revenge against their former master. In the end Reed decides they should leave the Red Ghost to his fate and they leave the moon in their rocket.

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