Posing as a new group of super-heroes, the Hyperclan have descended upon Earth, convincing everyone that they are a benevolent force. But as their true nature and plans come to light, only the World's Greatest Heroes can stop them. Standing side by side, Batman, Superman, Wonder Woman, Aquaman, the Flash, Green Lantern, and the Martian Manhunter take on these alien posers and come to realize that Earth needs a guardianship made up of only the mightiest of icons.