The Joker has become the emperor of the Earth and hired a crew of super-Hench men. But, how did he gain that kind of power? Sure, he’s always been insanely clever and sinister, but it never was about ruling the world. Once given the power by Mr. Mxyzptlk the Joker couldn’t resist but to play with the laws of physics. The Emperor has even convinced his people that, “two plus two equals fish!” He even managed to transform the world into a giant cube, but that’s beside the point. Happily the Joker gained Mr. Mxyzptlk magic abilities, by fooling the man, and created a society were being insane makes you sane.
Joker & Harley: Even though the Joker doesn't chose Harley Quinn as his Empress, so that they can repopulate the world to his liking, he still shows much love for her when he kisses her and gives her the best seat in the house to watch the fireworks (The end of the world).
Even his Staff is made to resemble Harley, therefore he must love her.
Joker & Lois: Lois Lane has feelings for Superman, but shrugs them off because she knows Superman is a dangerous criminal. Also, in going so she finds a way to manipulate him using the feelings he has for her. Therefore gaining Joker's trust and becoming his Empress.
Joker & Batman: Nightly screams can be heard in the Joker's city, but nobody understands where it's coming from or who is uttering them. The answer is later found by Superman when he find a dead Batman come back to life to face another night of torture. When the time comes all Batman wants to do is kill the Joker, even if killing a man is against his rules. He has been tortured to the brink of insanity.
Bizzaro & Superman: Bizarro number one is the hero of the universe created by the Joker and Superman is the most wanted criminal. They fight every night and each time Bizarro wins, by placing Superman, the man who steals, back in Arkham.
Lex Luthor & the Emperor Unwillingly Lex Luthor was forced to become part of the JLA and dance around in a clownish attire. He is the most sane man in this supposedly heroic group. This is comedy worthy of a king.
Once this team realises the potential the Joker has and what he'd going to do with it they agree to fight to change the society to it's origin. But, is this possible? Can they fight someone as powerful as the all mighty Joker?