Namor is on Skull Island in the Savage Land as a prisoner of the Plunderer; The villain tries to entice the Sub-Mariner into becoming his partner in world conquest by trying to impress him with his powerful vibra-gun constructed from Plunderstone (the Savage Land's version of vibranium); When the local Swamp Men attack, Namor is freed and the Plunderer's base begins to burn to the ground.
First Printing: Nov 1967
Writers: Roy Thomas, Stan Lee
Art: Werner Roth, Dan Adkins, Marie Severin, and Herb Trimpe
Cover: Marie Severin and Dan Adkins