The following article contains spoilers for What If…?.
What If…? finally goes about depicting the nexus event to unite all the multiverses and ponder what would happen to the MCU if Ultron defeated the Avengers six years ago, though the outcome ends up greatly exceeding the expectations of Tony Stark’s creation for one of the series’ most entertaining episodes and a more faithful recreation of the original plot for Age of Ultron in Marvel Comics.
On the face of it, “What If... Ultron Won?” features a highly condensed nexus event that simply consists of Ultron seizing control of the synthetic body that was to become Vision right before sending the world into nuclear chaos that kills off most of the Avengers. The premise is simple, just like DC’s Peacemaker, Ultron loves peace and is willing to kill as many people as needed in order to attain it.
The episode actually opens up with a battle scene where two of the unlikeliest survivors tear through a horde of Ultron’s legions, making it clear for viewers that the world is in such a dire state that it’s up to Black Widow and Hawkeye to save it. As these two very normal humans set out to execute their last-ditch effort, The Watcher introduces a reality even he considers quite sad, and later on it becomes obvious why this one hits so hard for the show’s narrator.
Of course, before getting down to business the audience is told just how powerful Infinity Ultron really is, so as Thanos crashes planet Earth a bit earlier than expected Ultron proceeds to slice him in half to seize control of the rest of the Infinity Stones. From here on, What If…? moves on to do what it does best, creating entirely new Marvel stories that really shine at their brightest when they’re not based completely on a single movie but instead take fans on a new ride that’s new and unfamiliar.
Ultron certainly delivers on that, as his new powers only boost his ambition for peace at all costs as he embarks on an intergalactic crusade to deliver peace across practically all of the MCU’s worlds, whether it’s Asgard, Sakaar, Xandar, or Ego himself, no planet is immune to Infinity Ultron’s threats of peace as Captain Marvel finds out when she’s ultimately killed by him, though not before reminding everyone of the many Terminator references in the episode. Regardless of all the interplanetary doom, things really get out of control when Ultron’s heightened sense of awareness sniffs out The Watcher’s voyeuristic tendencies and he uses his powers to barge inside the multiversal gallery.
As What If…? has slowly revealed more realities, the series keeps on bringing the Watcher closer to these worlds as symbolized by his image becoming clearer and clearer, until this time he actually comes way too close to the wrong individual. This makes The Watcher's foreshadowed protagonism in What If…? a consequence of his guilt over potentially even ruining the larger live-action multiverse pandora box that was cracked in Loki, thus proving the all-seeing entity wasn’t that good at his only job and leading him to break his promise to not intervene towards the end.
Nevertheless, all that pertains to the larger scope of things, because meanwhile Natasha Romanoff and Clint Barton are trying to execute their earthly plan to bring down Infinity Ultron using the tech specs of one Arnim Zola. This is one of the more direct callbacks in the episode, and although eventually futile, the plan gives Black Widow and Hawkeye much-needed exposition to fully express the latter’s weariness that leads to Clint sacrificing himself this time around to save the world, rather than Natasha.
No matter how many diverse flashes of different parts of the MCU are briefly shown during Ultron and The Watcher’s showdown, it’s these two’s mission that administers the much-needed dose of easter eggs and “look at that!” moments, especially with more recent references like Black Widow nabbing her adoptive father’s Red Guardian shield. Naturally, none of that is enough because Infinity Ultron’s threat level rose to a level far out of reach for Zola’s analog signals.
In one of What If…?' s most eye-catching battles, The Watcher pulls out the big guns to hold his own against Ultron and make many wonder just how high he ranks in Marvel’s power rankings. The fight is quite lengthy for the animated show’s standards, yet it’s the perfect showcase for What If…?’s pristine quality animation and is more than enough to make one wonder how the final episode will turn out.
Eventually, The Watcher recognizes that he can't ward off Infinity Ultron by himself, so to amend the disaster he's brought on to the Multiverse he has to ask for a little help and that's when that handily kept and remorseful, yet cocky as ever Doctor Strange Supreme becomes quite useful. As The Watcher lands inside Strange's collapsed universe inside the crystal from What If...?'s fourth episode, he finally concedes it's time to intervene so prepare for a finale that will, at last, give proper payoff to that Doctor Strange and Captain Carter reunion teased in the trailers.
Overall, Ultron defeating the Avengers results in one of What If...?'s most exciting episodes due to how high the stakes are raised, and while it may not be clear if Party Thor's episode seven reality will be the first one that gets rocked by Infinity Ultron's Galactus-like might, this outing definitely makes him out to be the perfect powerful antagonist that calls for a team of new Avengers to form. At this point, the series could use a finale that's a bit longer than the rest of the episodes, especially if the closing chapter has to explain how Gamora gets her hands on her father's armor for the epic showdown.
Still, What If...? is a multiseason show, so do not expect The Watcher's plan to fully redeem his overreaching mistakes as whatever ensues after the multiverse Avengers stop Infinity Ultron could well play out to be the plot for season two. The Multiverse is just that complex, and Phase Four continues to roll out with Shang-Chi, Eternals, and Spider-Man: No Way Home, the series' writers should relish the chance to work with all this new content that they've barely touched upon with a couple of WandaVision and Black Widow nods.