Taking over a TV station in Las Vegas, the Joker announces that he has placed a series of bombs that will destroy the Strip in twenty-two minutes and fifty-one seconds if they are not stopped by the Justice League. With the whole world watching Joker's version of reality television, the League must first get past the Joker's own super-team, the Royal Flush Gang. However, the threat imposed by the Joker is not as simple as it seems, and Batman must track down his location to stop his nemesis.

After Earth is attacked by a Gordanian battleship, the League is aided by an army of hawkmen from Hawkgirl's home planet of Thanagar. The Thanagarians offer to help Earth build a shield to defend against the Gordanians, but Batman discovers that this is just a ruse. Hawkgirl finds herself torn between her allegiance to Thanagar and her commitment to the Justice League, as well as between her betrothal to the Thanagarian commander Hro Talak and her deep budding romantic love for Green Lantern, John Stewart.