An advanced craft hovers over the Egyptian desert: the ship belongs to Baron Zemo who has been asked by Sin to locate a hidden base established long ago by her father, the Red Skull. Knowing the ground is booby-trapped, Zemo gives them both teleportation discs to get them gently to the surface. He locates the secret entrance and Sin produces a key, unlocking a door that admits them into an underground chamber; there they are attacked by long-dormant security robots. Sin, who remembered they were there from her childhood visits, takes great delight in shooting them to pieces, much to her partner’s annoyance. After the guardians are destroyed, she leads him into a Nazi shrine and picks up a huge tome from an altar. It is bound in the blue skin of slain Atlanteans and contains the record of the Red Skull’s greatest failure….
Germany, February 1942: The Red Skull observes as the sorcerers of the Thule Society sacrifice the bodies of captured Atlanteans to beg a gift of the occult powers they serve. The gods answer by sending down the weapon desired by the Skull…but it lands in a far off area. The impatient Nazi mastermind orders the Thules to find it….
The next day, Captain America and Bucky locate the abandoned camp of the Thule Society. Namor, the Sub-Mariner is with them and they try to prevent him from seeing his butchered countrymen but he storms in anyway…. After giving the Atlanteans an honorable funeral, an enraged Namor brutally questions a captive Thule priest and they are directed to Antarctica. The Red Skull and his party have located the smoking crater in which lies the weapon of the gods. The object cannot be moved so the Skull orders the Thule priests to stay there until they learn to control it…but their sensors detect another being there….
The three heroes have arrived on the scene in Namor’s jet but the craft is plucked from the sky by a savage giant. Namor attacks it just as Nazi soldiers surround the heroes. Bucky holds off the enemy with machine-gun fire while Cap and Namor battle the giant monster. The Red Skull, in his plane, opens fire with heavy gunfire and the ice breaks apart, dumping Bucky, the monster and several Nazis into the icy waters. Bucky tosses a grenade in the giant’s mouth. Cap halts Namor from pursuing the Skull in order to get the freezing Bucky to safety. Cap takes comfort in knowing they thwarted the Red Skull’s master plan. Meanwhile, at the Nazi base, the Thule priests cast protection spells as they build a shelter to guard the ornate war hammer which fell from the sky….
At this point the Egyptian tomb begins to quake, the result of a final booby-trap. Sin (carrying the book) and Zemo escape to the surface. She then shoots out his teleportation device, transports herself up to the hovercraft and takes off. As the stranded Zemo vows revenge, Sin dreams of her father’s failure becoming her greatest triumph….