As alien invaders (vaguely modeled after the White Martians from the DCU) who were accidentally awakened on Mars begin to take over the Earth, Superman and Batman rescue J'onn J'onzz who telepathically summons Wonder Woman, Hawkgirl, the Flash, and Green Lantern to defeat the invasion. Superman gathers everyone at the newly built Watchtower funded by Batman (through Wayne Aerospace's R&D budget) and asks to be part of a team, which he dubs the Justice League.