Earth seven greatest heroes unite against the threat of an alien invasion and decide to remain together to defend Earth against attacking aliens, sorcerors, super-villains, and any other threat that might arise. Among their number are the Martian Manhunter, last survivor of Mars; Superman, the super-powered last survivor of the planet Krypton; Batman, the Dark Knight Detective; Green Lantern, wielder of an alien Power Ring; The Flash, the Fastest Man Alive; Hawkgirl, Winged Wonder and policewoman from the planet Thanagar, and Wonder Woman, Princess of the Amazons. Starting with the third season, the show was retitled -Justice League Unlimited- and now the core members, under the guidance of the Martian Manhunter, command teams of specialist heroes brought together to deal with specific crises they are best suited to handling.