When Roxy Rocket tears into Metropolis, she tells Superman that Batman is missing, meaning Gotham City is being overrun by crime, so she came to Metropolis to try her luck there. Supes heads to Gotham to investigate, where he finds and assists Robin (Tim Drake) with foiling a robbery. When the trouble is over, Robin is hesitant to tell Supes about what's going on, but he's immediately surprised by what the Man of Steel knows...
- Superman: Where's your boss?
Robin: [shrugs] Around.
Superman: Alright, let's try this another way. Where's Bruce?
Robin tells Supes that Bruce had called and told him he'd be away on business and that he shouldn't worry, but, according to Robin, "he wasn't himself", and the fact that he simply bailed and didn't ask Nightwing or Batgirl to fill in was suspicious - Nightwing and Batgirl had traced the call to Romania and were now chasing down Ra's Al Ghul, suspecting he might have kidnapped Bruce. When they see the Bat Signal light up, Robin laments that it gets worse every time Batman doesn't show. However, Supes has an idea. When Commissioner Gordon and Detective Bullock shut down the signal, deciding Batman's not coming, the Caped Crusader (actually Supes in disguise) and Robin swoop in. "Good evening, Commissioner."
After the brief conversation with Jim, who tells them that Bane is back in town with a refined Venom formula (with Superman trying to keep his cover despite doing a bad job of it even with an authentic voice), Superman and Robin head to Wayne Enterprises to investigate Bruce's disappearance, starting with the computer records in his office - Bruce had sent a video message to Lucius Fox explaining he was taking a impromptu vacation, which contradicts what he told Robin about being away on work, but the fact that he's smiling is the weird part. They tracked the message to New Zealand, meaning Bruce is either hopping the globe, or someone's hiding his actual location by faking the traces. Superman, using his superhuman sight, finds nanites on some nearby papers, and a needle in the phone's earpiece - someone has injected nanites into Bruce, and is controlling his mind. Now, who in Gotham would know about such technology...?
After interrogating the Penguin for the Mad Hatter's location (Supes picks up on Batman's interrogation methods rather quickly with a bit of instruction from Robin), Bat!Supes and Robin crash a meeting between Hatter, Bane and Riddler. Bane is actually thrilled, as he didn't want to be forever denied an opportunity to break the Bat. Riddler uses a cage to trap Robin, and traps Bat!Superman's arms with a contraption, enabling Bane to deliver a brief smackdown, before seemingly crushing him with an Easter Island head. However, Superman pushes the huge stone statue off him (shocking the villains by sending it flying across the room), breaks the contraption, and wipes the floor with Bane, while Robin frees himself using Riddler's cane, cuffing him and lifting him into the air with the cage. Superman uses his super speed to confuse the Hatter and capture him. Later, at the Gotham PD, Hatter confesses that the nanites aren't his - he's stolen from the best, but these outclass anything that he's ever seen, speculating that they might even be alien in origin.
While analyzing the message to Lucius, Superman and Robin speculate that whatever aliens have kidnapped Bruce need him for something, and discover the sound of rocket fuel in the audio, meaning it was likely recorded at Wayne Aerospace. They investigate the site, and discover that it's full of activity, even though it's not supposed to be active. The rocket that is being developed has weaponry that Supes recognizes as Kryptonian. Then they see Bruce arrive, who tells everyone at the site to go home. When all the scientists have left, Braniac emerges from a hidden compartment, and prepares to kill Bruce now that he's no longer useful to him, but Bat!Supes and Robin intervene, and Supes deduces that Brainiac broke into Bruce Wayne's computers during his partnership with Lexcorp, saw that he could build him a rocket to leave Earth, and brainwashed him to make him authorize the project. While Brainiac compliments Batman's deductive skills, he notes that Batman is just human, and promptly blasts him. However, all this does is reveal who happens to be under the cowl.
- Superman: Today's been full of surprises. *Punches Brainiac out a window*
Brainiac attempts to escape in the rocket, and Superman gives chase, with Superman destroying the rocket's turrets with heat vision, and uses Braniac's own tentacles to short-circuit and destroy the rocket, along with Braniac himself.
Back in the Batcave, Bruce is feeling much better, as the nanites self-destructed along with their master. Superman warns him to check his computer systems in case Braniac left a part of himself around. Bruce mentions that the city's been busy while he was gone. Superman's response? "Nothing the kid couldn't handle. For someone who's supposed to be such a loner, you sure know how to pick a partner."
And with that, now that Gotham's protector is back in action, Superman heads back to Metropolis, with a job well done.
This episode contains examples of:
- Aesop Amnesia: Defied. When it's all over, Superman suggests that Bruce look over his computer systems and make sure Brainiac didn't leave anything behind.
- Armor-Piercing Question: Superman's "Where's Bruce?" breaks right through Robin's stonewalling and tells the Boy Wonder that Superman knows enough to be trusted with the more sensitive aspects of an investigation into Batman's whereabouts.
- Blood Knight: Bane. He's excited to see Batman alive and well, as it means he still has a chance to break him. Unfortunately for him, Superman happens to be in the cowl that evening.
- Boxed Crook: After "Batman" and Robin capture the Mad Hatter, he basically serves as this; before they directly take him back to prison, they have Hatter examine the nanites that were used to take control of Bruce, allowing him to confirm that the nanites are of alien origin and give them a vital clue to the party responsible.
- Brains and Brawn: Alluded to by the Riddler, though the man he's talking to is a recognized Genius Bruiser himself.
- Breaking the Bonds: Riddler ties Bat!Supes up with a metallic straitjacket device, allowing Bane to pummel him a bit. When Superman stops holding back, he breaks the device.
- Call-Back: How Brainiac brainwashed Bruce is one to both “World's Finest” and “Ghost in the Machine”. He got into Wayne Enterprises' computers due to the brief partnership with Lexcorp, whose computers he'd previously inhabited. Superman even advises Bruce to wipe his computers noting Brainiac tends to leave a bit of himself behind.
- Charles Atlas Superpower: Robin invokes this as an explanation for how "Batman" can somehow survive being crushed under some 2-tons (give or take) stone statue and lift it off himself with little effort.He's been working out.
- Costume Copycat: Batman being invincible served to spook the villains of Gotham even more, enhancing Batman's legendary status.
- Curb-Stomp Battle: After Bat!Supes stops holding back on Bane, he proceeds to wipe the floor with him.
- Didn't See That Coming: Brainiac is surprised when he blasts who he thinks is Batman only for Superman to emerge from the resulting fireball, having taken on the guise of Batman with Bruce Wayne having gone missing (due to Brainiac kidnapping and brainwashing him for his plans). His reaction is typically understated:Kal-El. This development was highly improbable.
- Distressed Dude: Robin is briefly trapped in a cage by Riddler. However, he doesn't take long to free himself, and to add insult to injury, he cuffs Riddler's arms to the bars and leaves him hanging in the air as the cage rises.
- Does Not Know His Own Strength: When Penguin refuses to give up any information, Robin suggests that Superman kick over his desk. He does—not like a Badass Normal would, but like someone with Super-Strength. Penguin is suitably freaked.
- Dull Surprise: A justified example when Brainiac the emotionless android/supercomputer learns who is really wearing that Batman costume.:Kal-El. This development was highly improbable.
- Failed a Spot Check: Lex Luthor, albeit implied rather than explicitly stated. Whatever off-screen security precautions his techs took to secure the LexCorp systems after "Ghost in the Machine" clearly failed, as a copy of Brainiac's program survived and made the jump into Wayne Enterprises' systems during "World's Finest". Of course, given that later events reveal that Brainiac had been inhabiting Luthor ever since that time, this may have been intentional on his part.
- Foreshadowing:
- Tim tells Superman that Batgirl and Nightwing went to Romania to interrogate someone named "al Ghul" about Bruce's disappearance. Superman will be meeting him soon enough...
- When Clark first spots the nanites on the paper while investigating Bruce's disappearance, there are only three and their position resembles Braniac's symbol.
- The Friends Who Never Hang: Roxy is surprised that Superman's unaware of what's going on in Gotham—thinking heroes had various club meetings. Superman remarks he and Batman aren't exactly friends.
- From a Single Cell: A programming variation. After Brainiac's defeat (and having learned from past experience), Clark advises Bruce to do a pass on his systems just to be safe because of this trope.
- The Gadfly: As the villains freak out over "Batman" lifting the statue Bane just dropped on him, Robin smugly tells them "he's been working out".
- Hoist by His Own Petard: Bruce's corporate partnership with Luthor back in "World's Finest" is what allowed Brainiac to emerge from hiding and make the jump into Wayne Enterprises' systems.
- I Am Not Left-Handed: Superman has to hold back when he fights Bane, but after Bane is led to think he's won, Superman stops holding back. It's both hilarious and awesome at the same time.
- Identity Impersonator: Superman filling in for Batman.
- I'm Standing Right Here: Robin momentarily forgets that Superman's technically an alien and not a human.Robin: Bruce is being controlled by aliens? Eww!
Superman: I'm deeply hurt. - Insult Friendly Fire: Superman and Robin find out that Bruce Wayne is being mind-controlled by alien nanites.Robin: So he's actually being controlled by aliens?! Eeeewwwwwww!Superman: I'm deeply hurt.Robin: Sorry.
- Internal Reveal: Robin learns that Superman knows Batman's Secret Identity.
- Irony:Superman: [to Bruce] I have to say, for a guy who's supposed to be such a loner, you sure know how to pick a partner.
- Jack Bauer Interrogation Technique: Superman is initially reluctant to use this on The Penguin, but with a little urging from Robin, he emulates Batman's manner of interrogation superbly.
- Locked Out of the Loop: Downplayed, but neither Bruce or Alfred apparently told Tim that Superman learned Batman's true identity during the Metropolis incident. Clark uses this as an in-universe Wham Line to get Tim's attention.
- Masquerading As the Unseen: Superman pretends to be Batman when he visits Gotham and finds out Batman is missing and teams up with Robin (who's in on it) to find him. It helps that Superman has a similar build to Batman and can impersonate Batman's voice.
- Mass "Oh, Crap!": Bane, Riddler and the Mad Hatter are in various states of panic when Superman, still disguised as Batman, not only starts pushing the moai head Bane dumped on him, but then sends it flying across the room.
- Mugging the Monster: Bane is excited to fight Batman. Unfortunately for him, Superman is impersonating Batman.
- Mythology Gag: When Superman (as Batman) lifts the statue, Robin "explains" it by saying that he has been "working out". Clark Kent does the same thing in Superman II.
- Nice Job Fixing It, Villain: If Roxy Rocket hadn't went to Metropolis to cause trouble and get Superman's attention, he never would have learned that Batman was missing and gone to Gotham City to help Robin find him.
- Likewise, if Brainiac had selected anyone other than Bruce Wayne to build his vessel, Batman wouldn't have gone MIA and the chain of events that brought Clark to Gotham would've been averted. Bruce also likely wouldn't have even realized one of Clark's enemies was hiding out in his hometown, either.
- Non-Action Guy: During 'Batman's' fight with Riddler and Bane, the Mad Hatter spends the entire time hiding behind a pillar or running away.
- Not Me This Time:
- Since Bruce is under mind control, Robin immediately suspects the Mad Hatter is behind it, but Hatter tells them that the technology being used is far more advanced than anything he's ever made, and they find out it's actually Brainiac.
- Earlier, Nightwing and Batgirl are mentioned as being in Romania, where Bruce's phone call came from, to track down Ra's al Ghul, believing he kidnapped Bruce. It's a red herring and Ra's has nothing to do with Bruce's disappearance.
- O.O.C. Is Serious Business:
- Bruce Wayne's behavior while brainwashed — and specifically the fact that he's smiling — causes Robin, Nightwing, and Batgirl to all instantly suspect that something's up.
- The Mad Hatter notices "Batman" break character three times (using super strength, super speed, and smiling) and comments on the first two, but doesn't draw any conclusions before getting distracted trying to figure out Brainiac's mind-control nanites.
- Oh, Crap!:
- Penguin after "Batman" kicks his desk into a wall.
- Bane right after "Batman" shoves off the Moai head and breaks his bonds, realizing he's about to get a whooping.
- With Bruce Wayne standing there under mind control, Brainiac proceeds to set Batman on fire. Good thing Superman is wearing his costume under Bat's.
- The Rat: The Penguin plays this role in the episode, after a bit of desk-kicking encouragement.
- Recycled Animation: When Superman (as Batman) punches Bane for the first time, there's a full screen frame of a fire explosion, which is reused footage from "Where There's Smoke" when Volcana blasts Superman with a fire ball in the parking lot. This is used again later when Superman blows up the lasers of Brainiac's ship.
- Sequel Episode: To "World's Finest" (following up on Clark and Bruce's first meeting and team-up) and "Ghost in the Machine" (as the next installment of the Brainiac arc).
- Small Role, Big Impact: Roxy Rocket only appears in the opening of the episode, but she is the reason Superman learns of Batman's disappearance, starting the events of the episode.
- Spanner in the Works: By alerting Superman to Batman's disappearance, Roxy Rocket accidentally ruins Brainiac's master plan (and the unrelated plan by Bane, the Riddler, and the Mad Hatter).
- Superman Stays Out of Gotham: Averted by necessity, though Superman has to reluctantly adopt Batman's methods to get things done. However, he does an admirable job of it with Robin's assistance, and he has a bit of fun using his superpowers discreetly to fool Batman's enemies (first by proving to be out of Bane's league even with the Venom serum, and confusing Mad Hatter with super speed).
- This Cannot Be!: Bane presumably crushes "Batman" with a heavy moai head. Then it suddenly starts moving.Mad Hatter: That's not possible.
- Villainesses Want Heroes: Roxy Rocket spends most of her screentime flirting with Superman.
- Villain Respect: While still holding humanity in contempt, even Brainiac has to compliment Batman's deductive abilities.
- Villain Team-Up: Bane, The Riddler and the Mad Hatter are planning to do this in Batman's absence before Superman and Robin show up.
- Voice Changeling: Superman is able to precisely imitate Batman's voice... and Robin's, for that matter. Robin is NOT amused.
- Written-In Absence: Nightwing and Batgirl left town to search for the missing Bruce.Robin: Batgirl traced the phone call to Romania. They went over there to find some old guy who might've kidnapped him. Ghul something.
- Wrong Genre Savvy: The characters initially think they're dealing with a Batman-level villain. Instead, it's the monotone alien computer. The same goes for Gotham's villains; Bane assumes he can win a physical bout with Batman using higher doses of Venom, but the stuff won't get him far against the Man of Steel.
- You Have Outlived Your Usefulness: Brainiac comes close to doing this to Bruce; thankfully Superman and Robin arrive in time to prevent it.
