Each member of the Trinity faces off against their arch-Nemesis in their respective home base cities. The villains think they've got the upper hand then they get beat as always. I gotta say I enjoyed see Bats, Sups and Wondy hanging out in a diner with a jukebox. Loved seeing Luthor, Joker and Cheetah in the Legion of Doom swamp fortress .
The Whole divide and conquer plan and to attack at the heroes respective headquarters was an awesome idea but without a doubt the best confrontation was Luthor vs. Batman in The Batcave (Alfred dressed as the decoy Batman) it was brilliant how Batman outsmarted Luthor by using Luthor's ego and admits he'd rather die in the Batcave than in front of the world. Luthor decides the latter and has everyone teleported to the Hall of Doom. Naturally, Batman continues the mind game and the Big Three escapes and the fight is televised across Earth and space.
50 years later, the Prez is about to open. Clark Kent, Diana Prince, and Bruce Wayne are present. Kent and Prince have gray streaks. Bruce is in the wheelchair from Kingdom Come. The donated item is the jukebox from the Star City diner. Prez is confused but is stoked. Then giant robots attack! Kent jumps into a booth and Prince does her spin. Costumes are the same. They ask Bruce if he's coming. He says he wouldn't miss it. The wheelchair morphs into a Batsuit. He stands and flies off to join them as they bash the robots.