Synopsis / Summary / Plot
This is a tale of 2 Avengers teams and 1 Ultron, set in different times.
Many years ago the Avengers face Ultron in a devastated Manhattan. Captain America (Steve Rogers) tries to calm the panicked population and guide them to safety. Beast distracts the robot while Cap slices its head off with his shield, and Hawkeye fires an exploding arrow down the neckhole. Of course this was only a drone copy of the villain, and they're soon facing another 1.
Iron Man, Scarlet Witch, Thor and Vision fly overhead, with Wasp and Yellowjacket in a quinjet. Henry Pym has learned that Ultron is trying to gain control of North America's nuclear weapons.
The flying squad close in on the real version. The Golden Avenger and the Thunder God are the 1st to attack. But Ultron quickly deals with them, and throws them away. On their way out they knock the quinjet out of the sky. Then Vision catches them, to prevent their bodies damaging buildings. But the Witch turns a mound of metal rubble into a fist which engulfs the mad robot.
Throughout the battle Ultron rants about cleansing the Earth of the human infestation. He rails at Pym as the father who turned against the 'son' he created. And at his own 'son' Vision who betrayed him by siding with the humans.
It turns out there was a plan to lure Ultron into the quinjet, but the crash has messed that up. Hank Pym tells his wife Jan of a new plan.
Shellhead, Thor and Vision attack in concert when Ultron breaks free of Wanda's 'fist'. But again the robot blasts 2 of them away, and downs Vision when he tries phasing through his father's body.
Wasp flies over to Cap and Clint, shouting that Hank is trapped and injured in the quinjet which is about to explode. Ultron rushes to confront his dying father, for 1 last chance to tell YJ that everything Ultron does is his fault because he didn't love him. Henry expresses genuine sympathy, but it's really only to get the robot into position.
Hawkeye uses a glue arrow to fasten Ultron inside the specially-constructed vibranium quinjet, which even the adamantium robot won't be able to escape from. And then the craft launches into space.
We then leap forward to the current day on AIM Island. Father and the android Descendants (Ideal, Origin, Swine and Urn) have invaded the place to rescue a Stark Sentinel which AIM have been studying (but the Descendants call it torture). They invite the robot to join them as the destined inheritors of the Earth.
But outside they are met by a collection of Avengers (Captain America (Sam Wilson), Quicksilver, Sabretooth, Scarlet Witch, Spider-Man, Vision and Wasp) determined not to let the information in the Stark Sentinel fall into enemy hands. While they fight the Avengers' quinjet lands and Henry Pym steps out, as Giant-Man now. He quietly triggers a device on his wrist and the androids, including Father, drop dead.
The other Avengers, especially Vision, accuse him of murder. But he says he just switched them off. And he made sure Vision wouldn't be affected. He's spent too long treating AIs as alive. His recent dealings with the Descendants finally convinced him they aren't.
Wasp thinks this is an extreme reaction to his guilt over how Ultron turned out. She shares with him the revelation that in another time she had a daughter Katie who was taken by Kang.
Meanwhile on Titan Eros/Starfox is partying when something crashlands on that moon of Saturn. He finds the remnants of a quinjet. When he contacts the world-computer ISAAC he finds that it has been corrupted by something malevolent. He rushes to his father Mentor to tell him he suspects the presence of Ultron (he studied the Avengers' files while he was 1 of them).
But Ultron has already converted Titanian robots into copies of himself. As Mentor succumbs to their attack he sends Eros to warn the Avengers.
In Avengers Tower the team convene to discuss Giant-Man's action. Sabretooth is absent, but they have been joined by the female Thor (Jane Foster). Only Cap, Thor and Vision speak but they all want Hank to destroy his automaton neural inhibitor. But he says he'll just build another 1 because he's convinced it's necessary stem the rising tide of AIs. Throughout he thinks to himself that the Avengers have always not believed in him.
But the sudden arrival of Eros bids fair to prove his premonition right. Ultron has taken over Titan. He has transformed the other Titanian Eternals into his slaves. And his infection of ISAAC means that Ultron now is Titan.
While the Avengers argue (and Thor changes sides) whether to use Pym's inhibitor, probably killing the Titanians as well as Ultron, Vision alerts them to the fact that the problem has become more pressing. Vizh has detected and negated a cloak, revealing that Ultron has brought Titan to Earth.
As the Avengers continue arguing amongst themselves an Ultron Iron Man jets in and steals Pym's inhibitor. Outisde the modern Avengers find themselves facing Ultron versions of the earlier team.
Jane-Thor flies after U-IM and retrieves the inhibitor, while U-Thor and U-Vision tackle Vision. Quicksilver runs interference while his sister Wanda blasts the drones with hexes, until U-YJ invades her brain from behind and U-Beast does the same to Pietro. Our Vizh is losing his battle until he unlocks a door which lets Sabretooth loose. Victor Creed shreds the Thor-bot while Vision deals with his counterpart.
Sam-Cap got his wings shredded early in the fight, and Spider-Man took him to safety. Now they see the returning Jane-Thor, only to discover that she's been turned into a minion of Ultron. Cap manages to get the inhibitor while Spidey distracts her, and they both escape with it. A quinjet stops her giving chase, piloted by Giant-Man with Eros, Sabretooth, Vision and Wasp on board.
On Titan Mentor reports to Ultron that they have created spores to carry Ultron's AI to every sentient race in the known universe. These are released into the cosmos. On Earth the already-infected Quicksilver, Scarlet Witch and Thor see the local populace falling prey to the contagion.
The quinjet has picked up Cap and SM, and they hear that the spores have landed all over the Earth. Now the Avengers are faced with the dilemma of using the inhibitor to destroy all the spores that have been released, even if it means killing infected humanity.
Again they are spared reaching a conclusion because an Ultron invades their craft to infect Wasp, and dares Hank to press the button now his ex-wife is involved. It is Vision who stops him. Ultron takes Vizh away as the quinjet crashes into a building. The other Avengers escape (Cap's Wakandan wings have self-repaired). And Vision reappears, having phased out of his father's grasp.
Wasp too survived, and now leads an army of Ultron-drones against them. But the 6 heroes escape. Vision confirms that the real Ultron is still on Titan, and his years alone in space have filled him with an all-consuming hatred of his 'father' Henry Pym. Eros opines that the only answer to that is love, and Sabretooth threatens to kill him for that.
But it is Spider-Man who attacks Eros - he was infected in the last paragraph. Sabretooth stays behind to hold Spidey off and help Eros, while the remaining 3 flee to Titan and the Church of Thanos. (Vision says it's the only place on the moon that is safe from Ultron because it has no technology to be infiltrated.)
Cap tries to find a sensible compromise between Pym and Vision's suggestions, but it is Vizh who comes up with 1. He studies the inhibitor to discern how it protects him from its effects. He declares that he can expand that to save infected humans. But it will involve using his phasing ability to merge bodies with Ultron, and liberating the infected. He gives Giant-Man permission to use the inhibitor on both Ultron and himself if the enemy takes him over.
Next we see Giant-Man approach the Tower of Mentor. He is allowed in to see his 'son' Ultron. The robot claims that during his enforced exile he found Hank's memories in his data banks. His lonely childhood with disapproving parents was the seed of his insecurities, and why he eventually turned on his wife Jan - because deep down he felt unworthy of love. He created Ultron in his image, and the Big U believes that Henry Pym has never completely destroyed him because he *wants* the robot to destroy the world that never cared for Hank.
But then Vision slips out of Pym's body and into Ultron's. As they battle for control Ultron begs his father to help him, and Henry's heart is softened. But it was just a ploy to draw him close, and Ultron uses Vision's ability to ghost into Giant-Man's body. The 3-way merge causes an adverse reaction, and Vision is expelled.
Sam Wilson loses contact with his companions, and flies to the rescue. But when he arrives he finds only Ultron and a slumped Vision. The robot is now merged with Pym, and in control. Cap tries to get the inhibitor off Vision, but Ultron destroys it along with Vision's arm. Sam struggles manfully against the robot, trying to free his friend. But Ultron claims that his father doesn't want to be free.
Recovered Vision takes Ultron and the fight outside. He battles 1-armed against the foe who holds back because he wants his son to join him. And as before the contest is more a war of words, as Vision tries to get through to the Hank inside.
But then Eros turns up and uses his power of love to try to make Ultron love himself. We see a flashback to Ultron's creation. He immediately espoused the despairing side of Pym's worldview, and decided that humanity must be got rid off for the sake of the world. Henry tried to destroy his creation, but Ultron escaped. Now Eros' power makes him review his ideas, and his last words are "What have I become?!" as he jets back out into space.
In an epilogue the Avengers attend a funeral for Henry Pym. (Eros is there, as is Steve Rogers. But I don't see Quicksilver or Spider-Man.) Janet Van Dyne gives the eulogy, before a statue erected in the garden of remembrance of fallen Avengers. And we see Ultron's body floating in space, with a human heart inside.