- Killer Shrike
- Count Luchino Nefaria
- Blizzard (Death)
- Mr. Fix (Death)
- Whiplash (Death)
- Black Knight
- Titanium Man (Justin Hammer)
- Iron Man Armor MK II
- War Machine Armor
- Titanium Man Armor
- Blizzard Armor
- Zombie gas (First and only known appearance)
While pulling an all-nighter, Iron Man battles the Black Knight, who is scared out of his mind and trying to get out of town. He eventually escapes after knocking Iron Man into a truck. Both Whiplash and Blizzard are down, and the friends wonder if it's some vigilante getting rid of them, or perhaps the competition? Stark International workers are surveying outside the ruins where the armory is hidden - they fear Justin Hammer wants to turn it into a testing ground for weapons. Tony encourages Howard that they must stop Hammer from pulling Stark International into the weapons business. At Hammer tower, they discuss how to handle Stark's return. Hammer has captured Count Nefaria and now he wants to use him as a test subject on his new weapon, Z-Gas, as he thinks Nefaria is blackmailing him. Sasha freaks out that he risks creating the zombie apocalypse. The real blackmailer calls in with a demand for a billion dollars. Hammer threatens Fix to track the source, and takes off in the Titanium Man.
Just then, Iron Man arrives at Hammer Tower to snoop around, but seeing Titanium Man take off, he follows. The Unicorn and Killer Shrike are counting up cash to get out of the country. They are frightened they will follow the rest of Hammer's hired goons, but Unicorn consoles him - just as Titanium Man crashes the place. He accuses them of being the blackmailers, they accuse him of being the one offing their colleagues. Shrike makes a run for it, just to bump into Iron Man. He exclaims that he does not wish to fight, and holds metro commuters as hostages unless Iron Man will fire repulsors at himself. Tony deflects the shots off his refractory coating and knocks down Shrike, capturing him. He hauls him back to the warehouse, where Unicorn is barely alive after Titanium Man's rampage. Killer Shrike begs Iron Man to take him to jail, hoping he will be safe from Titanium Man there.
Roberta and Howard are going over the legalities of Stark International, Tony and Rhodey arrive, suggesting they should play around the rules same as Hammer. Howard exclaims that would be just as bad as what Iron Man does, destroying as much as he saves. He is not impressed, and calls Iron Man an amateur. Hammer is afraid Killer Shrike will reveal their mutual illegal business to his lawyer, Matt Murdock, in order to get a reduced sentence. Sasha just laughs at him... until he suggests dropping Z-gas inside the city to meet his goal. Pepper acquires Shrike's transfer route, and War Machine and Iron Man set up posts to protect him - when Titanium Man strike again! He makes it off with Shrike and interrogates him in the gas chamber - but he doesn't know anything. The heroes intercept a transmission. Fix receives another call for blackmail, and Hammer must realize Shrike was not the blackmailer either. He accuses Sasha. The blackmailer disables security, and the heroes sneak in, just in time to stop Hammer from executing Shrike.
Hammer erects a force field, and zombiefies Shrike in the chamber. He gets up, screaming for "Braaains!". He initially attacks Sasha but she easily kicks him off, as does Iron Man. He reveals he has broadcasted Hammer's admissions of criminal activity live from his helmet camera. Fix confesses that he has allowed the transmission to happen, and it was he who blackmailed Hammer as revenge for what he did. Desperately Hammer runs for the Titanium Man armor, finally revealing his double identity to the heroes. He sets off a zombie gas bomb on the roof, and flies off, War Machine at his heels. Tony takes an incendiary bomb in a hope to ignite all the gas and render it harmless, but the bomb soon ejects many pods and begins its spread over the city. His plan succeeds all the same, and he takes off to assist War Machine. With Extremis, he forces Titanium Man to let War Machine go, and disables his armor, opening it to pull Hammer out. He drops him into Hammer tower, where Fix traps him in a gas chamber. Iron Man kills Fix in order to try to stop him and breach the chamber, but too late - Hammer has been turned into a brain hungering weakling. Rhodey suggests they call S.H.I.E.L.D. and have them examine if the zombie effect can be reversed.
The power over the company returns to Howard Stark, and he publicly thanks Iron Man for once telling him to not give up, no matter what one is up against.
- Roberta Rhodes mentions a court case called "Lieber Vs. Heck", which is a reference to Stan Lee (aka Stanley Lieber) and Don Heck, the creators of Iron Man.
- Attorney Matt Murdock is specifically mentioned in this episode. Murdock does not appear on camera.
- The Punisher is referenced in this episode.
- Though not confirmed, it's possible the zombie gas is a reference to The Return of the Living Dead, where the first infected were exposed to a gas that would eventually turn them into zombies. Similarly, the zombies in the movie say "brains", marking the iconic catchphrase of zombies in pop-culture.