At school, Ronnie is teaching chemistry using football plays when he asks a student to open the window. He's frozen by the villainess Killer Frost, Ronnie's old girlfriend. Batman arrives and knocks her back, and Ronnie and Jason merge into Firestorm. They fly down to assist, and she insists that Ronnie isn't innocent because he broke up with her by text message, and made her pay for all of their dates. Firestorm and Killer Frost go head to head, and Batman manages to wrap her up while Firestorm smashes her support ice. As she's taken away, Killer Frost promises that she'll be back, and Batman warns that archenemies can be dangerous.
High above Earth, Batman and Aquaman board the new Justice League's Watchtower satellite and greet their newest members: Blue Beetle, Guy Gardner, Booster Gold, Fire, and Ice. Aquaman wonders if Batman has the best ability after what happened to the previous League, but Batman insists that it's necessary. Booster Gold immediately hits on the ladies, and they all complain that it's hot. Martian Manhunter, the League's strategist, arrives and explains that the air conditioning is malfunctioning. Skeets offers to help, and Martian Manhunter irritably accepts his assistance.
Batman calls the League to order and explains that he sent Question to infiltrate Apokolips and learn about the threat of an alien invasion. As Batman tries to decipher Question's last transmission, he asks Martian Manhunter to show them around. He starts boasting of his arm wrestling match with Superman, but Aquaman complains that he doesn't know how to tell a story. Guy Gardner finds Green Lantern Hal Jordan's quarters and goes in, but discovers that Booster Gold has already claimed them. A fight breaks out and Aquaman tries to stop them but soon ends up fighting. Martian Manhunter tries to stop them without success, and gets angry when Guy Gardner smashes his cookies. He transforms into an alien octopus and attacks the others.
Their fight is interrupted when the Watchtower sensors detect teleporting Boom Tubes appearing all over the globe. The new League members start focusing on their individual needs, and Martian Manhunter says that the League is a team. He rallies the heroes to fight.
A few hours, Darkseid's parademons have conquered a city and captured all of the heroes. Kalibak gloats over his captives, but Batman manages to free himself and tricks a parademon into freeing the other heroes. They escape and go to Batman's auxiliary Batcave beneath the Lincoln Memorial. He contacts Martian Manhunter aboard Watchtower, who is still trying to repair the air conditioner with Skeets. Martian Manhunter briefs them on Darkseid's plan to set up a mass transport device between Earth and Apokolips. Darkseid will then bring the bulk of his forces through and transform Earth into a world of burning firepits.
Martian Manhunter has the heroes split into three teams, but before they can leave, Kalibak and the parademons smash into the auxiliary Batcave. The heroes realize that they followed the signal of Booster Gold's cell phone as he texted his agent. The heroes fight back, taking the battle outside. Batman heads for the Boom Tube generator, but Kalibak activates it and creates a giant portal. Darkseid's flagship descends.
Darkseid comes down from his ship and prepares to annihilate Batman with his Omega beams. The Caped Crusader dodges them but is knocked down, and Darkseid notes that he's only a human with a few toys. However, the other heroes launch a massive energy blast... which Darkseid causally deflects. He gestures and a wave of energy knocks them back, and Batman accuses him of refusing to face a mere mortal without his godlike powers. Darkseid is glad to relish the opportunity to fight on purely physical terms. The two of them fight, but Darkseid is still too powerful for Batman to stand against.
Once Batman is down, Darkseid starts to obliterate him... but the generator kicks in and creates a series of Boom Tubes, pulling all of Darkseid's forces off of Earth. Darkseid and Batman are both pulled in, but Batman fires a line and manages to stop his flight. Darkseid grabs him, but Batman cuts him loose and Darkseid goes tumbling back and disappears with his forces.
In the aftermath, Question emerges from the chaos, disguised as a parademon. He sabotaged the controls, and assures Batman that Darkseid won't be able to repeat his attack.
Later, the heroes celebrate aboard Watchtower, and Guy can't help pointing out that Batman didn't save the day. Batman admits that it feels pretty good. Guy and Booster Gold start arguing over the celebration cake, and accidentally hit Aquaman. He leaps into battle, while Martian Manhunter notes that the team shows some promises. He turns on the air conditioning... and the power goes out across the satellite.
Darkseid first appeared in Superman's Pal Jimmy Olsen #134 (November 1970) and was created by Jack Kirby. After killing his brother and mother, Prince Uxas became ruler of Apokolips and took the name Darkseid." He launched a war on rival planet New Genesis, but was forced to sign a treaty. Since then, Darkseid has schemed to destroy New genesis, conquer Earth, and unlock the secret of the Anti-Life Equation. In recent years, he engineered the death of the New Gods, only to see them reborn in human bodies. Darkseid took the identity of "Boss Dark Side," and eventually created a new body for himself, only to meet his death at the hands of Batman. Darkseid is arguably the most powerful of the New Gods, with physical prowess matching Superman's, as well as the Omega Sanction, beams of energy which allow him to blast or disintegrate most opponents, or banish them through time and space.
Tora Olafsdotter first appeared in Justice League International #12 (April 1988) and was created by Keith Giffen, J.M. DeMatteis, and Kevin Maguire. Tora is a member of a magic-wielding tribe of Norseman, and has a metahuman ability to project cold, snow, and ice. She joined the Global Guardians and eventually became a member of Justice League International. She died in battle with Overmaster, existed as a ghost for a while, and then was brought back. Since then, she has remained primarily independent while coming to terms with her new existence.
J'onn first appeared in Detective Comics #225 (1955) and was created by Joe Certa and Joseph Samachson. He was accidentally teleported to Earth and stranded, and took on the role of a superhero. He was a founding member of the Justice League of America and has served in most of its incarnations. The character has also appeared in the 1997 Justice League pilot, Justice League Unlimited, and The Batman. J'onn is in many ways a less powerful version of Superman, but also possesses telepathy, shapeshifting, invisibility, and density control powers. His only weakness is flame, which leaves him powerless.
Louise Lincoln first appeared in Firestorm (Vol. 2) #21 (March 1984) was created by Gerry Conway and Al Milgrom. A friend and student of the original Killer Frost, Crystal Frost, Louise duplicated the experiment that had given her mentor her powers, and gained a similar ability to absorb heat and project ice and cold. She went on a series of rampages against Firestorm, seeking revenge for Crystal's death, and has since become a full-time criminal.