The room devolves into chaos as everyone scatters, shielding themselves. Kate hits the deck and rolls behind a couch, taking a moment to get her bearings. She would rather not use fire in here, but these things are in the air, and that's the only way she'll be able to get to them. She blasts fire at the ones above her, managing to hit some clear back into the walls. Others are just knocked off track and scorched, but it helps.

Glass breaks behind her, Thor's hammer flies past her vision, and things are breaking left and right — at least including some of the Iron Legion. And then a blue one flies in from the lab and starts blasting. Kate and others blast back until Steve jumps on its back and it slams him into the wall, throwing him to the ground. Nat and Bruce go running up the stairs, and Kate covers them, distracting the Legion that's firing down on them.

Tony finally jumps on it and seems to have it under control, so she turns to blasting others, running at the ones closer to the ground to punch, kick, and swing a nearby lamp at them before the metal warps and bends in her hands. As she punches and dodges attacks from one, it begins to repeat the phrase it was programmed to.

"We are here to help. We are here to help."

"Well, you're not!" Kate shouts back, kicking it back to the railing and watching it flip over the side. When it comes back up, she blasts it, sending it crashing to the ground.

She turns and blasts the last one as Clint tosses Steve the shield. Steve throws the shield at the scorched bot, breaking it into useless pieces.

Ultron still stands. "That was dramatic."

"Yeah, and who's fault was that?" Kate asks, breathing hard.

He ignores her. "I'm sorry, I know you mean well. You just didn't think it through. You want to protect the world, but you don't want it to change. How is humanity saved if it's not allowed to... evolve?" He looks down, picking up a broken bot by the head. "With these? These puppets?" He squeezes, popping off the mask and tossing the bot aside. "There's only one path to peace: The Avengers' extinction."

Thor throws his hammer, sending Ultron into the wall. Pieces fall to ground, the eyes and mouth of the head lighting up to his last phrase before it dies. "I had strings, but now I'm free."

~_~_~_~_~

They cleaned up some of the mess before heading into the lab, and then noticed the scepter was gone. Thor left immediately to track a bot that escaped. In all the chaos, Kate never even noticed it. As the mistake eats away at her, she focuses on trying to figure out what went wrong — except there's no data to refer back to.

"All our work is gone," she laments, trying desperately with Bruce to find something. Guilt, regret, and loss all build up in her chest. There might've been something in the data to help fix whatever happened.

"Ultron cleared out, used the internet as an escape hatch," Bruce says. Where is he? And what's his game plan?

Nat speaks up from the other side of the room. "He's been in everything. Files, surveillance. Probably knows more about us than we know about each other."

"He's in your files, he's in the internet," Rhodey says. "What if he decides to access something a little more exciting?"

Hill looks up from picking glass out of her feet. "Nuclear codes."

"Nuclear codes," Rhodey repeats as Kate's heart drops. "Look, we need to make some calls, assuming we still can."

Nat shakes her head. "Nukes? He said he wanted us dead."

"He didn't say dead. He said extinct," Steve corrects.

"He also said he killed somebody," Clint adds.

"But there wasn't anyone else in the building."

"Yes, there was." With a sigh, Tony pulls up an image of JARVIS, fractured, broken, and eaten away.

Kate swallows thickly, tears coming to her eyes. JARVIS was much more than a program, he was a part of the team — of the tower. Of home. "Can we fix him?"

"No," Tony whispers.

Bruce shakes his head. "This is insane."

"JARVIS was the first line of defense. He would've shut Ultron down, it makes sense," Steve says.

"No, Ultron could've assimilated JARVIS. This isn't strategy, this is... rage."

Thor's footsteps thunder through the room as he comes back, striding over to Tony and grabbing him by the throat.

"Whoa, it's going around!" Clint says.

"Thor!" Kate shouts, hurrying over but not physically intervening yet. Thor spares her an angry glance before turning back to Tony.

"Come on, use your words, buddy," he manages.

Thor glares. "I have more than enough words to describe you, Stark."

"Thor, the Legionnaire," Steve reminds him, prompting him to drop Tony.

"Trail went cold about a hundred miles out, but it's headed north, and it has the scepter. Now we have to retrieve it, again."

"The genie's out of that bottle," Nat replied. "Clear and present is Ultron."

"I don't understand. You built this program. Why is it trying to kill us?" Cho asks.

There's a pregnant pause, and then Tony starts to laugh. It causes both Bruce and Kate to shush him and ignites Thor's anger again. "You think this is funny?"

Tony continues to laugh. "No... It's probably not, right? Is this very terrible? Is it so- is it so- it is. It's so terrible."

"This could've been avoided if you hadn't played with something you don't understand-"

Tony's tone changes, darkening. "No, I'm sorry. I'm sorry. It is funny. It's a hoot that you don't get why we need this."

Bruce sighs. "Tony, maybe this might not be the time to-"

"Really?! That's it? You just roll over, show your belly, every time somebody snarls."

"Only when I've created a murder bot."

"We didn't. We weren't even close," Tony argues. He turns to Kate. "Were we close to an interface?"

All eyes turn to her, and she shakes her head, looking at the ground. She can't even bring herself to speak. But Steve does, incredulous, indignant. "I'm sorry, you helped create this thing, too?"

"Not to do this!" she retorts, pushing away the shame. This was never her intention, this was never-

"Well, it is doing this, isn't it?" Steve shoots back. He sighs. "The Avengers were supposed to be different than SHIELD."

"Anybody remember when I carried a nuke through a wormhole?" Tony continues.

Rhodey shakes his head. "No, it's never come up."

"Saved New York?"

"Never heard that."

"Recall that? A hostile alien army came charging through a hole in space. We're standing three hundred feet below it. We're the Avengers. We can bust arms dealers all the live long day, but that up there? That's... That's the endgame. How were you guys planning on beating that?"

"Together," Steve replies.

"We'll lose."

"Then we'll do that together, too." He turns to everyone else. "Thor's right. Ultron's calling us out. And I'd like to find him before he's ready for us. The world's a big place. Let's start making it smaller."

~_~_~_~_~

They start to do what they can, but there isn't much yet, and all of them need rest. But as tired as Kate is, she can't sleep. All she does is lay there and think about what she's done, what her one act of good turned into.

She should've expected it, should've known what would happen. Maybe if it were just Tony and Bruce, maybe if she didn't put her scarred hands on it... Her mind starts going back to the explosion, to what she did to herself. What she is. She can't think of it anymore and gets up, going to the lab.

She replays recordings of what happened, looking for something, referring back to JARVIS' notes to make sense of it all. Ultron's voice rings out through the room. "No, not yet. Not this... chrysalis." He can read people — vocal patterns, adrenaline spikes — which they didn't program him to do. He learned all that. Tony wanted him to use slang, not destroy everything. But Kate was there.

When Hill gets up early that morning, she finds Kate, and they start tracking the beginnings of Ultron's career. They can't go through the usual channels, and Rhodey has nothing. Steve comes in early, too, asking Hill for updates as they all walk up to the lab. He doesn't look at Kate at all, doesn't say anything to her. The guilt somehow multiplies as she watches her feet. Hill answers him, acknowledging nothing. "He's all over the globe. Robotics labs, weapons facilities, jet propulsion labs, reports of a metal man, or men, coming in and emptying the place."

"Fatalities?" Steve asks.

"Only when engaged. Mostly guys left in a fugue state going on about old memories, worst fears, and something too fast to see."

"Maximoffs." He sighs. "Well, that makes sense he'd go to them, they have someone in common."

"Not anymore." She shows him the picture of Strucker, dead in his cell with the word 'peace' written in blood on the wall. As they continue on, they meet Clint in the hall, talking on the phone. Kate wants to talk to him, see what he thinks, if he hates her, but then Steve goes over to him and she continues on with Hill, who at least is talking to her like normal.

She passes everyone the picture when they arrive, finishing with Tony. "What's this?" he asks, taking the tablet.

"A message," Steve replies, coming in. "Ultron killed Strucker."

"And he did a Banksy at the crime scene, just for us."

Nat shakes her head, sitting at a computer. "This is a smokescreen. Why send a message when you've just given a speech?"

"Strucker knew something that Ultron wanted us to miss," Kate says quietly, having already given it plenty of thought.

"Yeah, I bet he..." Nat starts typing on the computer, then sighs. "Yep. Everything we had on Strucker has been erased."

"Not everything," Tony says.

They all follow he and Hill, dragging up boxes and boxes of physical files. Kate didn't even know this was here or how far back they go, but she imagines a lot of this was inherited from SHIELD. Maybe stuff she never even had clearance to read. The spark of curiosity barely flickers, however, and only in Bucky Barnes' direction. But it just makes her think of Steve.

As they hunt through files back up at the lab, she stands next to him, trying to focus on reading but instead feeling the waves of angry tension radiating between them. She hates fighting with him — especially because he's usually right. Right now, he definitely is. So, to ease the tension, she finally speaks up, albeit in close to a whisper.

"You're in your element, aren't you?" she weakly jokes, only to receive a barely audible sigh in response. She frowns, though she knows she deserves it. "Okay, still mad at me. Cool..."

"A little bit, yeah," he replies, still staring at a file.

"You're talking to Bruce and Tony," she points out.

He finally looks at her, disappointment in his eyes. "But I know you better."

"No, you don't."

"Maybe not the details, but I know how you are. And I can tell what you're feeling pretty easily, Kate, and I know that bothers you, but there it is." He sighs, putting down the file. "This Ultron thing isn't even curiosity, is it?"

She turns back to the file, not wanting to admit it, to tell him plainly, to open up. But he deserves an answer, and an honest one. Anyway, it's not something Tony hasn't basically already said. "It was a way to help protect the world from outside threats."

"You're not a threat."

She stops. Sure, he can guess what she's feeling — it's not hard when she's angry and upset, besides — but she's never told him that directly. "What?"

"I gathered why you never fought, Kate. I see the way you fight now. It's not too hard to figure out how you think about yourself if you pay attention."

"Well, stop paying attention."

He bristles. "I just wanted to understand my friend a bit better, that's all."

She turns to him, angry — at him, herself, or both, she doesn't know — her hands glowing in an instant. "It was a way to make up for the threat that I pose to everyone I'm in contact with in every room that I'm in. Okay?"

His expression softens, if only a bit. "You can't make decisions based solely on your own guilt."

"Yeah? Watch me." She throws down the file before it can catch, then moving closer to Thor, who has the good sense not to pry into her thoughts and motivations.

"Known associates," Nat says, opening a new box. "Well, Strucker had a lot of friends."

Bruce skims through some files. "Well, these people are all horrible."

Tony stops him. "Wait, I know that guy. From back in the day. He operates off the African coast, black market arms." Everyone stops, looking at him with raised brows. "There are conventions, alright? You meet people, I didn't sell him anything. He was talking about finding something new, a game changer, it was all very 'Ahab.'"

Thor looks over his shoulder, pointing at something. Kate can't squeeze in the circle to get a clear view, not that she really wants to. "This," Thor says.

Tony squints. "Uh, it's a tattoo. I don't think he had it-"

"No, those are tattoos. This is a brand."

Bruce searches it on the computer, matching the picture with the records they still have. "Oh, yeah. It's a word in an African dialect meaning 'thief,' in a much less friendly way."

Kate pauses. "What dialect?"

"Wa- Wakanda."

Oh, crap.

"If this guy got out of Wakanda with some of their trade goods..." Tony starts.

Steve's eyes widen. "I thought your father said he got the last of it?"

Bruce looks between them. "I don't follow. What comes out of Wakanda?"

Kate looks at Steve's shield, propped up in the corner. "The strongest metal on earth."