At Avengers Mansion, the Scarlet Witch returns! Finally, she has found Captain America, the man she was looking for. Cap is startled, as Wanda sneaked up on him so quietly, he at first thought one of their enemies had breached into the mansion. Cap mentions that the last thing the Avengers had heard of the twins was that they were still losing their powers.
He stops speaking, noticing that Wanda is alone, without her brother, Pietro. Cap wants to know where Quicksilver is. Wanda, on the very edge of collapsing, starts crying. She doesn’t know where Pietro is and worries about him. Cap calms her down, promising Wanda that no matter where Pietro is, they’ll find him. He wants to know what happened.
Wanda reveals that, after the day hers and Pietro’s powers started slowly coming back to them, they decided to properly train them. Finally, once they were certain their powers had returned, the twins were ready to leave their native home in the Balkans and go back to the Avengers. She remembers Pietro taking goodbye from the Burgomeister, thanking him for the hospitality and kindness to their person. Burgomeister claimed it was nothing, with the honor being theirs as they wanted to make up for driving the twins out of town and acting like demons upon them, several years ago when their mutant powers manifested.
On that very moment, a loud, buzzing noise could be heard across the entire town. Wanda and Pietro didn’t know what it was, nor any of the villagers. But it was something scary and unnatural. Everyone looked up in the sky, and saw… a flying saucer! It was like many people in the United States claimed to have seen, though nobody believed them. The saucer was landing nearby at an incredible speed. Once the saucer had landed, the sound disappeared.
Pietro told his sister to stay back while he investigated, but Wanda defended that she was as much an Avenger like her brother was, so they departed together. They found the ship nearby the mountains and Pietro quickly spotted a door. He warned Wanda that he’d scout ahead and, should he not return, she should go warn the Avengers about it. Wanda tried to hold her stubborn brother back, but he ignored her warnings and left. Pietro runs through the open door, but it closed the second he’s inside! Wanda tried using her Hex powers to open the door, but it didn’t matter: no harm came to the ship. She almost started blacking out thanks to the strain, so she decided to stop and return to the Avengers to ask them for help.
Wanda mentions to Cap that she tried contacting Cap on the Avengers’ special frequency, but there was no response. Luckily, she was able to use her Avengers priority knowledge to initiate a jet of her own so she could return to the States as fast as possible. Cap explains that they just returned a few hours from Latin America, so Wanda must have tried contacting them while they were away. Steve has heard enough and suggests he gathers the other Avengers for a meeting.
Not long afterwards, Hawkeye and the Black Widow enter hading planned to go out for dinner. Hawkeye thinks Cap is overreacting again, but Cap warns otherwise and informs him that Quicksilver has been captured. This is Avengers business. Natasha thinks she better leaves them, but Hawkeye asks her to wait. He fully trusts her and thinks it’s about time Natasha becomes a fulltime member of the team. Cap explains that’s not just for them to decide, as they’ve got a special meeting to gather for that for which they haven’t got the time right now.
Goliath and Janet enter next. Hank claims he isn’t busy at all right now, and he votes no against Natasha’s recruitment. Janet tries to calm Hank down, wanting to know why Cap summoned them. Hank doesn’t listen, and mentions Natasha can’t join because, not too long ago, she was a partner with the Swordsman and Power Man, who attacked them. Hawkeye defends Natasha, joking that now that Hank is back to his normal size, he’s bossing around but he can’t run the entire show. Janet tries to tell Hank there’s no reason for him to get so upset. He thinks maybe not but, as an original Avenger, Hank refuses to see the team he helped form turn into a home for reformed super-villains.
Hawkeye shouts at Hank to back off, reminding him that it was him and the other new Avengers who helped prevent that the Avengers became just a name in the history books, while Hank spend most of his time taking vacations. Hank increases his size, defending that he was still fighting villains like Colossus while Hawkeye was sparring like a bad guy against Iron Man! Hawkeye doesn’t care how big Hank can get, with all the arrows in his quiver he can certainly take him out. Cap and Janet calm everyone down, knowing that everyone has been under a lot of strain recently, thanks to the battle against the Living Laser, but they’ve got some serious business going on right now. Hank and Clint calm down, promising they’ll fight another day.
Wanda is furious at how her teammates treat her after she returned to them. She warns that time is short, and that the saucer might have already departed along with her missing brother. She wants to know if the Avengers are going to help her or if she has to leave alone. Everyone agrees to help out and they depart into their aero-cars, ready to head for Europe. As they go, everyone agrees that Pietro is no pushover and can handle any situation heading his way. But, nobody really knows if the saucer really is from outer space and don’t even want to really think about it.
A few hours later, the Avengers arrive in Transia, the country where both Wanda and Pietro were born. But, Wanda doesn’t see the saucer around anymore! Cap calms her down, promising they’ll keep searching for Pietro until they have found him. A few minutes later, Wanda feels a force field nearby and tells Cap to change course. The ship’s detectors locate it as well, though the force field is almost naked to the naked eye. Cap didn’t know that Wanda’s powers included ESP and wants to know since when she developed a radar sense. Hesitating, Wanda thinks it must have happened during their stay here in the Balkans. Though not sure, she’s just glad to have it.
The ship lands. Once outside, Wanda recognizes that the ship has increased in size many times over and now occupies the entire village square! Cap tries smashing the force field with his shield, but with no such luck. Hawkeye wonders about the fact that the ship seemed invisible from in the air, and it looks like they don’t like visitors. He fires a blast arrow on the field. Even though it explodes, no harm has been done. Hank suggests he changes size and tries pounding on it, but Wanda holds him back. She just remembered something.
Years ago, when she and Pietro were still children, they used to play in a cave nearby. They always suspected it had off-shoots which ran under the village itself. She suspects that the invaders haven’t discovered the cave yet. Everyone thinks it’s worth checking out and tells Wanda to lead the way. They find the big cave and enter it. Cap thinks that they are almost above the force field, but still wonders how a saucer can change size like that. They stop as they find a strange, bright light, almost like daylight even though they are fare below the surface level.
They find an exit, and go through it. They land in a gigantic room, which lots of devices in it. It looks like one of those Japanese monster movies. Though Cap fears this situation is far more serious and sinister. They look in front and notice that, in the middle of the big room, there’s an even more gigantic glowing computer being installed. That must be the device that controls this ship and abducted Pietro. Yet, something is strange about the computer, as it almost seems alive and looking at the heroes.
Hawkeye wants to blast the machine, but Cap warns not to do it was they still don’t know where Quicksilver is. Plus, there’s some strange, evil aura hanging around this place that troubles him. Suddenly, the notice in a space below them, a man sitting in a strange mechanical chair with lots of devices around him. Wanda recognizes the man: it’s the Burgomeister from their village, who drove her and her brother out years ago but befriended them, like she earlier explained. She thinks that the giant computer brain must be using the poor man to gain information.
Suddenly, the computer begins to talk! It warns that the Avengers shall never learn who they are or where they came from. The Avengers recognize it as a computer voice, but Natasha wonders what the purpose of attacking the Earth is. The computer changes its mind, agreeing to fill in the heroes about at least that little fact, only because it suits him. They are introduced to IXAR, who comes from the star-sun Sirius. And he’s engaged into powerful warfare with powerful foes! IXAR claims that the puny planned called Earth means nothing to him and is just a pawn in a struggle that began centuries ago.
Cap whispers to his friends not to move because he wants to know what IXAR is all about. IXAR reveals to have traveled to Earth anyway because on this planet, there’s something he needed to win the war. The reason he’s here is because Earth is home to many so-called super heroes, whom IXAR wants to use in his war. He shows the Avengers his two first captives: giant experimental tubes descend, and hold captive the unconscious bodies of both Quicksilver and… the Scarlet Witch?!
Cap explains he isn’t so surprised: the Wanda with them is… an android! He had his suspicions when Wanda suddenly began demonstrating new powers, and the cave was a little too convenient. The android confirms, though the knowledge won’t save the Avengers. She starts changing shape, and transforms into a female android. She explains she’s an invention from IXAR. And the Avengers have walked into a trap, one from which they will never escape.
A panel opens, and an endless line of male androids enter the room! The female android reveals that they are actually called Ultroids, the most powerful and tireless weapons from IXAR. Once the Avengers have been captured, the plan is that their power floats through the Ultroids’ bodies and empower them. The Avengers aren’t impressed, as from the way they stand, it looks like they haven’t absorbed Pietro and Wanda’s powers yet. They start attacking, and IXAR orders his servants to protect themselves. Goliath rips open the floor, causing the non-expecting Ultroids to lose their balance.
Cap gets fired upon, though he manages to hide behind his shield. He continues the battle, though more and more Ultroids start surrounding him. Suddenly, the floor below him starts opening: Cap has been lured into a trap! He falls through a tunnel, and powerful shock rays start hitting him, which make Cap feel dizzy.
Hawkeye can’t believe Cap has been captured. He bravely continues the battle as well, but one of the Ultroids manages to sneak up on him and slams Clint on his head, making the archer faint. Hank notices and rushes to his teammate’s aid. Hank is in such a hurry that he doesn’t notice an Ultroid sneaking up, and hitting him with a powerful blaster cannon. Hawkeye has already recovered and gets up. He takes out a blaster arrow and fires it to destroy the cannon. Elsewhere, Janet has shrunk to Wasp size, so nobody could notice her trying to dismantle the control panel which holds Pietro and Wanda captive. Unfortunately, the panel is booby trapped with more shock rays and they hit Janet.
IXAR warns Hawkeye to surrender. He refuses and manages to blast a water pipe and a water pipe destroys his attackers. Clint takes off, but then gets surprised and captured by a powerful net! He fails to get out, but is glad that at least Natasha hasn’t been caught, and is their only hope of an escape. Natasha herself has made it to a balcony, and thought she’d better stay out of the battle in case anything went wrong. Now, she notices that the Avengers seem all to be captured and wonders about what to do next.
IXAR praises his minions for their fine work. The female Ultroid warns that not all Avengers have been captured yet and that the Black Widow is still running free. They both send out the Ultroids on the lookout.
Natasha thinks she better goes to rescue Quicksilver and Wanda first. She finds their holding cells, and one guarding Ultroid. Natasha lands down, trying to fake that she has been sent by IXAR to bring the prisoners to him. Unfortunately, the Ultroid is smarter than he seems and realizes it’s a trick. Having thought that might happen, Natasha moves close enough to focus her strength and punches the Ultroid down. She moves over to the control panels, but remembers what happened to Janet. She tries to figure out how to destroy it.
A voice suddenly warns Natasha not to move. Fearing it’s another Ultroid, Natasha strikes with her electronic bite. The person hides behind his shield, and is revealed to be… Captain America! Cap reveals he escaped by remaining unconscious long enough to use his shield to keep the walls from closing in on him. And luckily he awoke before the Ultroids arrived to capture him. But enough talk: they have to find a way to rescue the Quicksilver and the Scarlet Witch.
Natasha tells Cap to look below: the Ultroids have placed Goliath in a similar tube as the twins and bring him closer to IXAR. Cap fears that they’ll arrive here soon as well, which means they only have seconds to spare. Cap warns Natasha to stay back: he throws his shield at the transparent tubes, causing it to break a little and make an opening. But then, suddenly, the Ultroids have caught up on them, and strike the heroes from behind! Both the Black Widow and Captain America collapse, with IXAR laughing that victory belongs to him!