The Fantastic Four discover a hidden valley that serves as home to The Inhumans, a group of super-villains lead by the scheming red-haired beauty known as Medusa.
Doctor Doom, the armored monarch of a land called Latveria, sends the Fantastic Four back to the time of Blackbeard, demanding that they steal the infamous pirate's treasure.
The dangerously beautiful queen of a small, faraway country lures The Fantastic Four into coming to her rescue when rebels steal the source of her power.
Sue and Ben travel to the Negative Zone, with the help of a teleporting dog-like creature named Lockjaw, and bring back a giant cocoon that proves to contain Blastaar, a being with the ability to direct bomb blasts anywhere he chooses.
Doctor Doom causes a power outage that affects every machine in the United States and demands control of the U.S. armed forces, but Reed Richards knows what the evil egotist really wants.
Three gangsters befriend a little green alien they dub The Impossible Man for his ability to change into any shape. The naive extraterrestrial helps them rob banks, while The Fantastic Four try to warn him about his false friends.