Jimmy Olsen is announcing for an epic baseball game between Justice League International and the Legion of Doom. The villains are ahead by 3 at the bottom of the ninth, and Batman gives an inspirational speech to his teammates, saying they have to win for the children. Wonder Woman bats first, but Weather Wizard freezes her fly ball and Cheetah tries to tag her out. Amazo calls her out, but tells the truth and declares her safe with some assistance from Wonder Woman’s golden lasso. Lex Luthor deliberately walks Superman rather than let him score a home run, and Robin bunts, putting a player on each base.
Lex Luthor calls a timeout and berates his teammates, and then has Felix Faust enchant the heroes’ bats. Plastic Man and Green Arrow strike out, and Batman comes to the plate. One of the kids gives Batman his Little League bat. Unconcerned, Lex prepares to use his cybernetically-augmented pitching arm. Superman spots it with his x-ray vision and realizes that Lex has been cheating the entire game. Lex pitches two strikes, but Batman hits the third ball. When Weather Wizard tries to stop it, Superman destroys his weather wand with his heat vision. Batman hits a home run and his teammates carry him off the field.
Later, Joker has strapped Batman and Vicki Vale to a bullseye target atop the Gotham City Bridge As the villain flies overhead in a Joker-dirigible, he fires a giant exploding cream pie via catapult.
Lex Luthor emerges from STAR Labs, wearing his battlesuit. Disappointed at the lack of opposition, he fires energy blasts at the police. Superman arrives to save them, but his strength is no match against Lex Luthor’s energy blasts.
At the Museum of History, Wonder Woman calls upon Cheetah to surrender. Cheetah refuses and attacks with a pair of swords.
Batman uses a remote to use the Batcopter’s lasers to free himself. He airlifts himself and Vicki to freedom just in time, and then slices open Joker’s dirigible and sends him down into the river. As he falls, the villain insists that his plan was foolproof.
Lex Luthor confronts Superman, who tricks him into boasting that he has an unlimited power source that can match Superman’s strength. Superman destroys it with his heat vision and Lex throws a piece of kryptonite at him. The Kryptonian knocks it into the lead sewer system and Lex flies away, insisting it was foolproof.
Wonder Woman disarms Cheetah with her lasso and knocks her out of the building, as the villainess insists that her plan was foolproof. Superman and Batman call her to confirm that they’re still meeting. The heroes arrive at a diner in Star City to relax, play a song on the jukebox, and talk shop. Batman asks them about the superhero memorial time capsule. Each of them will contribute a personal item and they’ll dig it up in 50 years. They discuss what to donate but are interrupted when the food arrives.
At Legion of Doom headquarters, Luthor insists that they need a victory but Joker points out that their opponents know their every move. He suggests that they change opponents and the others agree. Joker chooses Superman, Luthor goes after Batman, and Cheetah boasts that Superman can’t resist her claws.
Wonder Woman returns to Paradise Island in her invisible jet to find something to donate to the time capsule project. Her mother Hippolyta insists on her staying to watch an arena battle. Joker, disguised as a woman, slowly gasses the Amazon warriors unconscious. When Hippolyta focuses her attention back on the battle, she is surprised to see that Joker has apparently triumphed. As he steps forward to claim his prize, the warriors start laughing maniacally. Wonder Woman realizes too late that it’s a trap as Joker stuns them with a joy-buzzer blast and unveils. After a brief struggle, he gasses her unconscious and claims her tiara.
Superman flies to his Fortress of Solitude in the Arctic and Cheetah slips in behind him. She attacks him and easily knocks him back, and reveals that she’s wearing a magical necklace that channels her namesake’s powers... and Superman is vulnerable to magic. When he tries to restrain her, Cheetah reveals that she has painted her razor-sharp fingernails with kryptonite nail polish. With the odds stacked in her favor, Cheetah quickly defeats Superman.
In the Batcave, Batman is in his civilian clothing and feeding all the requirements for the time capsule ceremony into the Batcomputer to come up with the perfect donation. It suggests a Batarang. As Alfred leaves for the night, Luthor teleports in using a tracking device. He fires at Bruce, who ducks into the caves. Alfred returns and dons a Batman costume, drawing Luthor’s fire long enough for Batman to don his costume. With his battlesuit, Luthor is easily able to defeat Batman and shutdown his Batmech. He then handcuffs the Caped Crusader with glue and unmasks him. Batman has a second automatic mask that protects his identity, and Luthor boasts that his fellow villains are finishing off Wonder Woman and Superman. Batman says that he’d rather die in ignominy then in public, and Luthor gets an idea. He slaves the other teleporters to his and departs with Batman.
Joker and Cheetah and their defeated opponents are teleported to Legion of Doom headquarters. They object, but Luthor says that he wants to broadcast their victory to the world. He activates a series of transmitters, intercepting communications across the galaxy. They declare final victory over the Trinity, the three most powerful heroes. Meanwhile, Superman and Wonder Woman why Batman convinced Luthor to broadcast their defeat. When he says that it’s the company, they realize what his plan is. Batman asks if the villains will take their respective spoils. Luthor refuses to give up Metropolis to Cheetah, and the other villains disagree.
As they argue, Batman frees Superman, who frees Wonder Woman, who frees Batman. The villains finally realize that their captives are free, and a battle begins. The supervillains briefly triumph over their own opponents, but the heroes soon regroup and team up to defeat each opponent. Across the galaxy, people cheer the heroes. The deadline for the time capsule arrives and the heroes wonder what to put in it.
Fifty years later, Teen president Prez Rickard opens the time capsule. In the crowd are the elderly Clark Kent, Diana Prince, and Bruce Wayne, the latter confined to a wheelchair. Prez opens the capsule and finds the jukebox from the diner. Giant robots attack the gathering and the heroes spring into action, with Batman’s wheelchair transforming into battle armor.