Set 1 year after Superman and Batman joined together to form the Justice League, Lex Luthor decides to even the playing field by forming a league of his own. He thus travels across the world, offering a spot to any of the super-villains on the FBI's most wanted list. He winds up recruiting The Joker, Reverse Flash, Cheetah, The Riddler, Black Manta, Dr. Poison & Scarecrow. Together, the legion plans to take out the Justice League and rule the world (of course). Each of them has a vital part in Lex's master plan to destroy, or at least disgrace the Justice League. Using Reverse Flash's speed, they're able to gain access to the Batcave, and manage to acquire Batman's files on the Justice League, containing everything from strengths to weaknesses. Using this information, Lex sends different members of the legion to fight their respective heroes, with an added bonus that'll allow them to incapacitate the hero. Wonder Woman is infected with a hallucinogenic serum that makes her see everyone as Cheetah. Batman is trapped in an endless maze filled with memorials to all of his past failures. Superman is exposed to red kryptonite, causing him to go insane. Flash is attached to a bomb that'll explode if he stops running or slows to under 100 mph. Martian Manhunter is infected with nanites that burn on contact with air. Aquaman is rendered hydrophobic by Scarecrow's fear toxin. Now it's up to the Teen Titans to save the Justice League & stop the Legion of Doom.