Former chief psychiatrist of Arkham Asylum and current inmate Hugo Strange has infected all of Gotham City with a zombie virus that, after 48 hours, will become irreversible. However, just to be sporting, Strange tips off Batman and Robin, giving them a chance to synthesize more of the drug and distribute it before Gotham is well and truly destroyed.
Tropes in this episode include:
- Carrying the Antidote: Strange happens to be carrying it on his person, but "accidentally" drops and breaks it when handing it to Batman. He also apparently creates way more antidote than is necessary for a single person, and is strangely willing to divulge its location. It turns out that it's a mind-altering toxin, and breaking it exposes Batman and Robin to it, who in turn try to expose the entire city to it to "cure" them.
- Crazy-Prepared: Batman is shown to have a backup cave that only he knows about, which comes in handy when (he thinks) his closest allies have been turned against him.
- Deadpan Snarker: After Robin suggests getting Bruce out of his speech by gassing everyone with knock out gas, Alfred comments that he’ll be sure to have blankets and pillows on hands, before high-fiving the boy.
- Find the Cure!: The premise of the episode.
- Foreshadowing:
- Batman and Robin are attacked by zombies almost as soon as Strange breaks the antidote. The antidote is actually the toxin, and Batman and Robin were exposed to the fumes.
- Batman is unable to find any trace of the toxin in the air shortly after its "release," which he chalks up to it dissipating quickly. Nor can he find any in the hair follicles of its victims. Of course, this is because Strange didn't actually release anything.
- Alfred is initially shown to be alright, with Bruce warning him to turn on the air filters and stay in the cave. Yet when the Dynamic Duo return, he’s been infected. Presumably, Strange’s chemical only works to alter perception of those not infected with it.
- The zombies yell at him about "poison" and attempt to spray him with something, despite Strange claiming that the zombies spread the virus via biting. Batman is the one who's been poisoned, and they're trying to spray him with antidote.
- When Batman visits Strange again, he's in a different room despite nobody actually being left to unlock his cell door. The police found out what he did and moved him to a higher-security cell.
- Strange claims that he'll only divulge the location of more antidote if Batman takes off his mask, but gives in rather quickly and tells him anyways. He's the one in a hurry, because he needs Batman to spread the drug before it wears off on him.
- Heroic BSoD: Robin has a breakdown in the Batcave when he realizes that he and Batman are completely alone in Gotham. Batman himself gets a dose when Robin, his surrogate son, is taken and turned.Strange: Of course, with all those zombies running around, I wouldn't feel comfortable going into that neighborhood . . . alone.
- Irony: Towards the end, before giving his speech to Gotham Town Square, Bruce can't help but mull that everyone is there to honor him, unknowing that they might've been infected with Strange's toxin by his own hand (Well, had Bruce not possessed the intelligence and patience to piece together the truth).
- Meaningful Echo: Batman warned Robin that Dr. Strange has a habit with messing with other people's heads. Later, Zombie!Robin's "Mess A Head" statement becomes a clue to Batman to help him realize Robin was trying to tell him Dr. Strange messed with his head.
- Might as Well Not Be in Prison at All: Averted. While Strange somehow has seemingly created a zombie virus and released it all across Gotham while confined in Arkham, he actually has no way of actually releasing it anywhere but directly in or around his cell. Instead, he manipulates Batman into helping him to spread it further.
- Near-Villain Victory: Batman is literally seconds away from spreading Strange's toxin to everyone in Gotham before he realizes how suspicious the entire setup is.
- Omnidisciplinary Scientist: This episode cemented Strange's role as this, in contrast to the Psycho Psychologist he was earlier in the show.
- Orcus on His Throne: Strange himself never takes an active role in the events after initially releasing the toxin. The room Batman finds him in even resembles a throne room.
- Our Zombies Are Different: This being The Batman, they're kung-fu zombies who can jump ten feet into the air and hold their own against Batman.
- Placebo Effect: Sort of. The toxin apparently requires the victim to believe that there are zombies, at least to some extent. Batman still sees Strange and Robin as normal humans because the former drank the antidote and the latter was wearing a gas mask during the "release." He begins seeing flashes of the "zombies" as humans when he starts to doubt Strange's version of events.
- "Stop the Hero" Twist: The GCPD, Barbara, and later Dick try stop Bruce and it isn't until the climax that Bruce realizes he was dosed with a hallucinogen and was about to expose Gotham to Strange's real toxin.
- Suspiciously Similar Substitute: The episode was originally going to feature Scarecrow as the villain, until
the writers were told he was still off-limits because of his appearance in Batman Begins, so they rewrote the story with Hugo Strange instead. Tropes Are Not Bad as the change is generally looked upon positively, as Scarecrow's involvement likely would have made the twist more obvious. - Twist Ending: Rather unusually for this show (which is why it works so well). The "antidote" Strange exposes Batman and Robin to is a toxin that makes them hallucinate that they're in a zombie apocalypse, in order to get them to spread the toxin to all of Gotham.
- Zombie Apocalypse: Strange causes one. Or so Batman thinks.
