Inside LexCorp, the Justice League's seven founding members and Amanda Waller have just been treated to the bizarre sight of Brainiac inside Lex Luthor's body. Brainiac explains that it inserted a microscopic copy of itself into Luthor's body years ago, back when it forced Luthor to build it a new body. Over time it manipulated Luthor to begin work on a replacement body, curing Luthor's Kryptonite poisoning and gave him super-strength as a byproduct. The last act Luthor was to accomplish was to transfer Brainiac's consciousness into the "more suitable" android body.

Having had enough exposition, the League attacks, but the Luthor/Brainiac hybrid knocks the League and Waller out of the building, then overcomes the leagues with mechanical constructs. Braniac announces it will digitize their knowledge, then delete their physical forms. J'onn J'onzz phases free of the restraints and smashes Brainiac's body, freeing the League. Brainiac converts the top of the LexCorp tower into an enormous skull-like robot ship, which the Justice Leaguers manages to destroy. Batman claims the fight was too easy, and the League realizes the attack was a diversion to allow Luthor/Brainiac to escape.

Under Brainiac's control, Luthor is forced to walk through the sewers in search of a place where it can repair itself. Luthor points out that Brainiac's programming is devoid of purpose: its ultimate end is to digitize, then destroy the entire universe. With nothing afterwards, Brainiac will have fulfilled its purpose and cease to function. Luthor says he can show Brainiac a higher purpose by providing it the one thing it lacks: imagination.

The League realizes since Brainiac's body is nano-technological, he will go to Cadmus to harness the power of the Dark Heart. Cut to Luthor and Brainiac doing just that. Brainiac assumes control of the nano-assemblers, allowing it to reshape matter. Luthor's body is submerged in the Grey Goo and emerges as a gleaming titan, a fusion of Luthor and Brainiac. With their combined intellect, they plan to absorb all Earth's knowledge and wipe it out in a single stroke. "And then...the galaxy! The entire universe! We'll remake the universe!"

The League founders head for Cadmus headquarters. J'onn calls for backup, but the recent attack on the Watchtower means they cut off from the other superheros. When they arrive at Cadmus, Luthor/Brainiac has reshaped the building into a Doomsday Device the size of a skyscraper. Superman urges Lex to fight Brainiac's control, only to learn he's now a willing participant.

Luthor/Brainiac conjures up android replicas of the Justice Lords that taunt their counterparts with their worst fears. Despite this, the League defeat their doppelgangers. Luthor/Brainiac blasts the League with energy beams, rendering all but the Flash unconscious. Luthor/Brainiac prepares to kill the Flash but he vibrates free. When Luthor/Brainiac taunts him the Flash runs away, only to come at the hybrid from the other direction. The Flash circumnavigates the globe faster and faster, using the energy buildup to begin disassembling Luthor/Braniac. Finally filled with the energy of the Speed Force, Flash is able to remove Braniac from Luthor's body, leaving him naked and helpless at the bottom of a crater.

As the League regains consciousness, they are horrified to see the Flash fade away. When Luthor gloats that he did indeed kill Flash, an enraged Supermand seizes Luthor, his eyes glowing red. Wonder Woman moves to intervene, but Batman stops her as this is Superman's decision. Superman calm down and tells Luthor he will live to face justice. Just then J'onn shouts that he is in psychic contact with the Flash. Shayera reaches in the direction J'onn is pointing, and and she is able to reach into the "Speed Force" where the Flash has been taken. The six Leaguers form a human chain and manage to pull the Flash free from the Speed Force. Nearby a relieved Waller tells the President to call off the air strike against Brainiac.

The next day, Superman addresses a crowd in Metropolis. He tells them that the League has been guilty of arrogance, and has alienated the people it was trying to protect. Because of this, the founders have decided to disband the League, and decommission the Watchtower.

In the silence that follows, the Green Arrow steps forward and delivers his own speech, arguing that the world still needs heroes like the Justice League. Superman, inspired by this sentiment, agrees that the League will remain, but need to remain in touch with the people, and suggests they will open an embassy on Earth. Batman excuses himself, giving a knowing wink to Green Arrow.

That evening at the Daily Planet, Clark Kent drops in on Lois Lane as she is finishing her story on the League. He is surprised to hear that she's using the adjective "ambivalent", and she shoots back that her job is to be as tough on Superman as she is on any subject, but only because he himself has set such high standards. After all, she finishes, "he's only human...you know what I mean." Smiling, Clark says he does, looking out the window to the deepening night.

Written by Dwayne McDuffie.

Tropes:

• All Your Base Are Belong to Us: After assimilating the Dark Heart, Lexiac converts Cadmus into his new headquarters.
• Ambidextrous Sprite: When Lexiac is knocked back after losing most on the metal on one arm, then the moment he flips over, the damaged and intact arms switch.
• And Then What?: Luthor asks Brainiac what he'll do if he succeeds in acquiring Earth's information and destroys the planet. Brainiac says he'll simply keep moving onto the next world until he's done. Luthor offers to show him a purpose beyond his programming.
• Art Evolution: Downplayed, but the flashback to "Ghost in the Machine" isn't stock footage. Rather, the entire sequence has been reanimated using Lex's Justice League-era character model rather than his original STAS design (to say nothing of digital line art and coloring rather than painted cels).
• Awesomeness by Analysis: After Lexiac escapes, the League's attempts to track their movements fail. So, they have to review the scant evidence they have to figure out where they could possibly be headed. Shayera posits they left Brainiac weakened and damaged, meaning he'll need to repair himself. Diana's counterargument is that Brainiac might just dump Luthor and find himself a new body. However, Clark — knowing Brainiac as well as he does — agrees with Shayera's assessment and that he'll seek out the highest technology available. And since he's fled LexCorp, J'onn thinks that means he'll go for S.T.A.R.. Labs — until Waller argues it has to be Cadmus. Shayera and Batman realize Waller's right; after all, this incarnation of Brainiac's now nanotech. And the most advanced nanotech currently on the planet are the remnants of the Dark Heart, which Cadmus confiscated the previous year.
• Beware the Nice Ones: The Flash is regarded as the nicest member of the team. But when push comes to shove, Flash shows he has the raw power to take down the godlike Brainiac/Luthor entity single-handedly.
• Bishōnen Line: After solidifying their alliance and getting an upgrade at Cadmus, Lexiac transforms from the grotesque Body Horror-filled monstrosity into a sleeker cyborg design.
• Broke Your Arm Punching Out Cthulhu: The Flash can never attain the speed he uses to beat Brainiac ever again on pain of being absorbed by the Speed Force.
• Call-Back:
  • Brainiac recalls how Darkseid double-crossed him. Similarly, Justice League-era Brainiac's desire to evolve into a true life-form was likewise established in that episode.
  • Luthor and Brainiac remake themselves into one perfect being by using the Dark Heart.
  • The return of the Justice Lords, even if they're just copies.
  • During the fight between the League and the faux-Lords, there are multiple references to the events of "Starcrossed":
    Lord Hawkgirl: (to herself) Do you think there's a single person on Thanagar or Earth that doesn't despise us?
    Lord Lantern: (to himself) We loved the traitor! Loved her and lost her, forever!
• The Cape: The episode ties off a running thread of Superman possibly doing what his Justice Lords counterpart did. When it looks like Flash has died, Superman clearly struggles with this, but his ideals win out.
  Superman: I'm not the man who killed President Luthor. Right now, I wish to Heaven that I were, but I'm not.
• Chain of People: When Flash is sucked into the Speed Force, the other six founding members of the Justice League form one of these in order to get him out of it.
• Chekhov's Gun:
  • The laser Brainiac hit Luthor with all the way back in Superman: The Animated Series actually injected him with nanites containing his code.
  • You remember back in the episode "Dark Heart" how the Atom commented that General Eiling was stupid for preserving some of the Dark Heart? He was right, and this is why.
• Chekhov's Skill: Flash’s ability to punch a hole through a person by vibrating his fist. After trying it out on his Justice Lord construct, he tries it again on a Brainiac-empowered Luthor and effectively punches Brainiac off him.
• Combat Tentacles: Shortly after revealing himself, Brainiac causes the LexCorp tower to sprout numerous massive tentacles and attack Waller and the League.
• Continuity Porn:
  • 8 real life years ago, Brainiac implanted a copy of himself inside of Lex Luthor and waited for an opportunity like Project Cadmus.
  • A subtle one dating back to when Superman first met Brainiac, where Luthor theorized in a then throwaway line that Brainiac could give to Humanity would be a potential cure for Cancer. Here, we find out that Brainiac managed to cure the Kryptonite-Based cancer that was affecting Luthor ever since Injustice For All, essentially proving Lex right all along.
• Crazy-Prepared: Retroactively with Brainiac during "Ghost in the Machine" when he covertly inserted a nanotech copy of his program into Lex's body. It was insurance just in case something went wrong with his rebuilt body (which it did, as Superman destroyed it).
• Criss-Cross Attack: Done piecemeal, wherein Lex Luthor, Brainiac and the Dark Heart all fuse together into a nigh-omnipotent cyborg that promptly hands the Justice League their asses. The Flash, however, begins running at Luthor at increasing speed, until he's circling the Earth between blows. In less than a minute, Luthor is reduced to a normal human, gasping and naked in a blast crater. Viewable on YouTube here.
• Curb-Stomp Battle: After he ascends to his new golden form and absorbs Luthor, the Justice League is absolutely no match for Brainiac. He dismantles them with ease, even incapacitating Superman (who had, in an earlier episode, proven totally capable of wiping the floor with Darkseid) with a single energy blast. Then Flash taps into a one-time maximal use of the Speed Force, and Brainiac ends up on the receiving end of this trope.
• Dangerous Forbidden Technique: The Flash taps into the Speed Force in order to defeat Lexiac, almost at the cost of his own life.
• Dark Reprise: A dark reprise of the JLU theme song is heard the Brainiac copies transform into the Justice Lords.
• Darkest Hour: The newly formed Lexiac prepares to bring about the end of the world. With the closest help an hour away, the Big Seven are the only ones in a position to stop it. In all the confusion, Flash is the last Leaguer standing.
• Deader than Dead: Brainiac, courtesy of Flash utterly annihilating his being with the Speed Force to the point that nothing remains.
• Death Seeker: After Lex is no longer merged with Brainiac, he tries to goad Superman into killing him by gloating about how he supposedly just killed the Flash. Recognizing that Lex is trying to stain Superman’s integrity as consolation for losing, Superman notes he wishes he was the kind of Superman that could kill Lex but ultimately isn’t and spares his life.
• Decoy Getaway: Lexiac's Skullship materializes on top of LexCorp and tries to get away, but when the League destroys it it was actually remotely-piloted: Lexiac was never inside.
• Deus Exit Machina: Much of the JLU are stranded on the Watchtower due to the Ultimen wrecking the Javelins and the telporters are offline. Also, Green Arrow reports those who were helping with the relief efforts are scrambling, but they're too far away to be of any immediate help. All of this leaves it up to the seven founders to deal with Lexiac.
• Did Not See That Coming: Lexiac completely writes off Flash as a threat. Problem is, Flash's powers prove to be devastating to Lexiac, and takes him down in moments once he stops holding back.
• Didn't Think This Through: Retroactively with Luthor during "Ghost in the Machine". Brainiac blasted Lex at point-blank range; he should have died. It never occurred to Lex to wonder why the blast hadn't killed him and thus he never considered Brainiac might have had an ulterior motive.
• Dissonant Serenity: In the Speed Force, Wally has an eerily calm voice when he bids his friends goodbye.
• The End of the World as We Know It: The newly remade Lexiac has this on the agenda.
  Lexiac: We are one, and we comprehend. We can build a machine that will allow us to absorb the information of the entire Earth in a single stroke. And then the galaxy, the entire Universe! We'll remake the Universe!
• Enemy Mine: Continuing on from last episode, with Brainiac now exposed, Waller and the League remained allied to try and stop him and Lex.
• Evil Is Petty: Lexiac attempting to gun down a restrained Flash. Dialogue makes it clear this is Luthor's desire to settle a personal score rather than Brainiac's logical response to a possible threat.
• The Fellowship Has Ended: The founding members decide to disband the Justice League at the end of the episode. Green Arrow convinces them to change their minds, to which an impressed Batman has a Call-Back to why he recruited Green Arrow in the first episode.
• Friendship Moment: After Flash vanishes, Superman has the opportunity to kill Lex in response. Wonder Woman is about to intervene, but Batman stops her, as he's absolutely certain that Superman will do the right thing and spare Lex on his own. He is proven right.
• Fusion Dance: After absorbing the Dark Hearts' nanomachines, the two of them use it to create a single body for them to share.
  Brainiac: I have learned from my encounter with Darkseid that Organic Beings cannot be trusted.
  Lex Luthor: I can't argue with that. But if you and I are one, truly one; trust won't be an issue will it?
  Brainiac: Agreed.
• Generic Doomsday Villain: Lex Luthor figuratively gets under Brainiac's skin after the latter literally got under his skin by accusing him of being one of these. Luthor points out that Brainiac had no real plans of doing anything with its vast store of knowledge and that it had no real reason for destroying the universe. Brainiac realizes Luthor has a point and agrees to a Fusion Dance so they can actually do something with all of that power and knowledge.
• Heroic RRoD: The Flash ends up disappearing into the Speed Force after defeating Lexiac, but the trope is ultimately subverted when the rest of the Justice League is able to locate the portal and pull him out of the Speed Force.
• Hoist by His Own Petard: Cadmus launching their assault on the Watchtower last episode. The Lexiac crisis is exactly the kind of situation Cadmus was formed to handle...if they hadn't taken themselves out of the fight. They threw everything they had into the Watchtower attack — a strike that failed, leaving their arsenal depleted, their forces stranded, and forced to rely on the very people they were trying to kill to stop Lexiac.
• Humongous-Headed Hammer: Green Lantern finishes Shayera's Justice Lord construct by repeatedly hitting her with a giant hammer. The real Shayera accuses him of enjoying it a little too much.
• Irony: The League's greatest challenge to date is a fusion of two of Superman's greatest enemies, and he's defeated not by Superman, but by the Flash.
• I'm Not Doing That Again: After being pulled out of the Speed Force, Flash says that he'll disappear for good if he ever pushes his Super-Speed powers that far again.
• "I Know You're in There Somewhere" Fight: Superman tries with Lex, only to learn the latter is now a willing partner instead of being a possessed victim.
  Lexiac: You're right. I am in here... and I like it!
• Let's Get Dangerous!: Lexiac writes Flash off as a joke. However, he quickly learns how dangerous the fastest man alive can be...
• Little "No": Flash when Lexiac says he'll kill him and bring about the end of the world.
• The Main Characters Do Everything: The founding Leaguers take on Brainthor alone, though it's justified. Half of the League is marooned on the Watchtower (thanks to the Cadmus incursion knocking out the Javelins and Transporters last episode) and the other half (at Cadmus ground zero) are at least an hour away even at top speed.
• Mecha-Mooks: Lexiac sending drones to fight the League as a distraction, and Luthor decides to turn these drones into copies of the Justice Lords.
• Mirror Match: Justice League vs. Justice Lords. At least, until the League takes a page from the X-Men book of tactics and pulls an Opponent Switch.
• Mr. Exposition: Brainiac goes into detail over how he got into Luthor's body and slowly influenced his actions. Flash interrupts him to say it's time to go to jail.
• Mythology Gag:
  • Flash's Justice Lord counterpart resembles the Reverse-Flash.
  • At the end, Batman quotes the ancient Roman line Who watches the watchmen to Green Arrow. The reference to Watchmen is unmistakable and speaks on whether the superheroes can be trusted to act in humanity’s best interests without being corrupted by their own power. Green Arrow’s assurance that they can is a rebuttal to Watchmen’s premise that they can’t.
• Near-Villain Victory:
  • Lexiac has the Flash restrained and a gun to his head, ready to kill him just as everyone feared.
  • Luthor gets another near-victory (albeit most certainly a Pyrrhic Victory) after Flash disappears into the Speed Force, when Superman is about to fry him in violation of his ethics.
  • Cadmus nearly gets what it’s been wanting for two seasons when Superman announces the Justice League will disband in the light of recent events. It’s only when Green Arrow gives an impassioned speech urging them to continue on that Superman reconsiders and suggests internal reforms to better assuage public concerns on their power.
• Neck Lift: A very angry Superman to Luthor when he thinks Flash just died.
• Nice Job Breaking It, Hero!:
  • Cadmus views themselves to be righteous, but keeping remnants of the Dark Heart robots in storage proved to be stupid as Lexiac fused them into himself to become even more powerful.
  • Likewise, Waller throwing the full weight and might of Project Cadmus and its assets into the invasion of the Watchtower last episode. Not only did the strike fail, but it completely depleted Cadmus' entire arsenal — meaning Waller has nothing left to stop Luthor/Brainiac and must rely on the Justice League to bail her ass out.
• No-Holds-Barred Beatdown: After Flash is done racing around the world, he forces Lexiac to the ground and just starts punching him repeatedly at super speed. The end result is Brainiac completely destroyed, while a dazed Lex is still intact.
• Not His Sled: The episode suggests we’re going for a Crisis on Infinite Earths homage with Flash running so fast he disintegrates. But then The Power of Friendship allows his allies to save him from his fate, pulling him back to reality. (As noted below in Ret-Canon, this ended up being adopted by the comics in Final Crisis as a way to bring back Barry Allen from his original death)
• Nothing Personal: Luthor quips to Superman that Earth is a mere business trade-off for the power and immortality he stands to gain now.
• Off with His Head!: How Shayera disposes of Green Lantern's Justice Lord construct.
• Oh, Crap!:
  • Waller after shooting Brainthor in the opening minutes...and realizing her shots are ineffective and he's healing.
    Waller: I'll be dipped...
    Brainiac: Begone. (explosion of energy)
  • Brainthor when he sees part of his armor destroyed when the Flash punches him, and realizes the Flash is racing around the world to punch him multiple times, with increasing intensity.
  • The League when Flash disappears. Even Batman is stunned.
• Opponent Switch: Superman and Wonder Woman, as do Green Lantern and Hawkgirl (who take the chance to work out some frustration over their breakup).
  Wonder Woman: What do you say we switch dance partners?
• Physical God: Brainiac-Luthor, in his final form. Strong and durable enough to inflict a Curb-Stomp Battle on Superman and the rest of the League (the former having himself beaten actual gods like Darkseid) and in possession of various powers from shapeshifting, to technopathy, to vast intellect and knowledge, to telekinesis, to being able to create sapient beings with a thought (ones capable of trading blows with Superman, no less). He planned to use his newfound power to build a machine that would allow him to remake the universe.
• Power Incontinence: Flash taps into the speed force and runs faster than he has ever done before, able to pull Brainiac off Luthor with a near speed-of-light succession of attacks. He's nearly pulled into the speed force afterward, and is only yanked back by the League. He says he can never go that fast again, feeling he wouldn't be coming back if he did.
• "The Reason You Suck" Speech: The Justice Lord recreations do this to most of the Leaguers.
  Lord-Superman: We've lost their trust. The people are afraid of us. Power corrupts, after all. And who has more power than Superman?
  Lord-Hawkgirl: Do you think there's a single person on Thanagar or Earth who doesn't despise us?
  Lord-Green Lantern: We loved the traitor. Loved and lost her... forever!
  Lord-Flash: Slacker! Child! Clown! We have no place here among the world's greatest heroes.
• Red Eyes, Take Warning: How Superman considering using his heat vision on Lex is shown.
• Ret-Canon: This episode launched the idea that breaking the light barrier would imprison the speedster in the Speed Force unless they had an anchor (though this was hinted at in Crisis on Infinite Earths).
• The Reveal: Luthor has been an unwitting pawn of Brainiac since mid-STAS circa "Ghost in the Machine". When Brainiac shot Luthor in that episode, the blast carried a nanotech copy of his program. This copy of Brainiac has laid dormant in the years since and subtly affected Lex's body (curing his cancer) and actions (the construction of a new AMAZO host body).
• Revenge: When Lexiac is poised to gun down Flash, Luthor's personality suddenly becomes dominant, making it clear this is about petty revenge and spite for being inconvenienced rather than just a logical concern about a powerful superhero still being standing.
• Screw This, I'm Outta Here: Subverted. Luthor thinks Flash ran off to save himself, but Flash just needed a running start.
• Shapeshifter Guilt Trip: Lord Superman briefly morphs into Luthor when the real Superman has him on the ropes, forcing the latter to back down.
• Ship Tease: When Batman leaves, he says the League has his number if they need him. A smiling Wonder Woman notes she most certainly does.
• Shut Up, Hannibal!:
  Lord!Flash: Slacker! Child! Clown! We have no place here among the world's greatest heroes!
  Flash: Says you! I got a seat at the big conference table. I'm gonna paint my logo on it! (pow)
• Swapped Roles: After Flash vibrates Brainiac out of Luthor, he comments he feels funny while flickering and disappears into thin air to the other founding members' horror. Luthor taunts that he managed to kill Flash after all, a very unamused Superman lifts him by the neck and charges his heat vision. Wonder Woman tries to intervene only to be stopped by Batman. This bring to mind "Hereafter" when Superman is seemingly killed by Toy Man's giant robot laser with Wonder Woman grabbing Toy Man and threatening to punch a hole right through his head with Flash stopping her.
• Take My Hand!: As she reaches into the Speed Force that the Flash had disappeared into, Shayera tells him to take her hand as she and the other five remaining founding members try to pull him out. As they're pulling him out, you might notice that Shayera is holding him by the wrist and that he didn't actually take her hand.
• Tempting Fate:
  • Flash makes quick work of his double by vibrating his hands and running the double through with it. He makes the following remark, yet he has to do it again to defeat Lexiac.
    Flash: Never doing that again.
  • As the page quote shows, Lexiac mocking the Flash and thinking the Flash is running away—right before the Flash starts to hand Lexiac his ass.
  • And again right after, mocking the "death" of the Flash, in front of a bunch of very alive heroes and a very pissed off Superman, while completely defenseless, leading to his line of realization below.
• This Is Gonna Suck: Once Brainiac manages to restrain the founding members, he says he will claim whatever valuable data they have and eliminate them, a painful process that involves electric tendrils being attached to their chests.
  Flash: I am so willing to wait my turn.
• This Is the Part Where...: You kill me right?
• Took a Level in Badass: Brainiac. In his DCAU previous appearances, it was a huge threat, but its personal combat abilities were lacking. Superman was able to his most powerful body one on one without much trouble. Here, he's able to challenge Superman and the rest of the League in combat (with his Combat Tentacles being so strong even Superman can't break out of them) before he absorbs the Dark Heart, fuses with Luthor, and gets his golden form. After that? He curb-stomps the Superman and the League while barely lifting a finger. Only the Flash's Dangerous Forbidden Technique can stop him.
• Trash the Set: LexCorp Tower, a staple of Lex Luthor's business ever since the second episode of Superman: The Animated Series ends up destroyed by Brainiac (who had built a starship to try escaping inside the upper levels of the tower).
• Underestimating Badassery: Brainiac/Luthor regard Flash as the least of the Justice League. This is a bad move on their part, as Flash shows he had the raw power to take them down by himself.
• Visual Pun: Wonder Woman destroys Lexiac's machine by throwing a Javelin at it.
• Voice of the Legion: When Lexiac speaks, both Luthor and Brainiac's voices are heard simultaneously. Dominance shifts depending on the subject: Luthor does the egotistical boasting, while Brainiac is only interested in the task at hand.
• What He Said: When Flash interrupts Brainiac's exposition:
  Flash: Hate to interrupt this special live performance of The Thing With Two Heads, but it's time to go to jail now.
  Waller: What he said. (shoots Lex/Braniac; It does bupkes.)
• You Are Better Than You Think You Are: After Superman and the other founders decide to disband the team, Green Arrow tells him different with a speech about heroism and the importance of the fight. He caps it off this way.
  Green Arrow: The world needs the Justice League. And the Justice League needs you, Superman.
• You Called Me "X"; It Must Be Serious: When trying to pull the Flash out of the Speed Force, Hawkgirl and Green Lantern call him by his real name, Wally.