Justice League: Crisis on Two Earths
Justice League: Crisis on Two Earths is a 2010 American animated superhero film released on February 23, 2010. It is based on the abandoned direct-to-video feature Justice League: Worlds Collide, which was intended as a bridge between the then-concluding Justice League animated television series and its then forthcoming sequel series Justice League Unlimited. Crisis on Two Earths was reworked from the Worlds Collide script to remove references to the TV series' continuity. The film is directed by Lauren Montgomery and Sam Liu and written by Dwayne McDuffie.
Plot
In an alternate universe, heroic versions of Lex Luthor and Joker (called the Jester) steal a device called the "Quantum Trigger" from the headquarters of the Crime Syndicate When an alarm is tripped, the Jester sacrifices himself to allow Luthor to escape from the Syndicate. Luthor escapes to the Earth of the Justice League by activating a device that enables interdimensional travel.