The last few days had been… good. Tony could confidently say that. It was a little weird, to be honest. It wasn't that Duo let his guard down, exactly, but he was definitely trying more. He was a total gearhead, so that helped. He could, and would happily, spend hours working on cars with Tony. He was more familiar with space-worthy engines than cars, but he never had to be told something more than once, and he integrated the information seamlessly into his current knowledge banks.

It was actually not unlike Tony's own learning processes. While his estimation of Duo's intelligence continued to inch upward, he was comfortable saying that Duo wasn't on his level of genius. It was a tiny bit of a disappointment, but at least he was not, like, average. Tony didn't really think he'd love him any less if he were, but it'd definitely be harder to try to relate to him. Tony had always struggled to connect with people who couldn't keep up with him, which was, pretty much, everyone.

Duo could keep up with him, and Tony would be lying if he said it wasn't exhilarating. It wasn't the same as being as smart, because, well, no one, not even Bruce, was as smart as Tony. But there were a few people who were smart enough to keep up with him. Bruce was the only one who came readily to mind on the science side, but there were people who could keep up with him and feed his energy and help push him even farther—Rhodey in college was the first he remembered—and Duo was the same.

Vision decided that they should all be eating at least one family-style meal, and he and Duo had been cooking for at least two meals a day. They were mostly doing lunch and dinner, since while no one was on lockdown, per se, everyone, especially the pardoned Avengers, had been strongly recommended to keep low profiles. It was still awkward a lot of the time, but Duo got Wilson on his side somehow, so, between Wilson and Vision, he was noticeably denting barriers. Mostly, anyway.

That meant that when Maria Hill and another Preventer agent Tony thought he should know showed up in the middle of the day, they were all just sitting down to lunch. Tony was surprised to see Hill in a Preventers uniform.

"We apologize for the lack of notice," the vaguely familiar agent said. "I'm afraid I haven't had the chance to meet most of you personally, but I'm Sylvia Noventa. I've been selected to serve as a liaison between the Avengers and United Earth Sphere Nations as you transition from SHIELD overview to Preventers partnership. Agent Hill, whom you should all know, will be assisting as well."

"Agent Hill," Tony said. It was too easy—he couldn't not. "Thought real hard about that one, did you?"

"It was available," she said in her usual clipped tone. Tony didn't take it personally. She talked to Fury like that, after all. "Agent Darkside, it's nice to see you again," she said with a nod of acknowledgment to Duo.

"Agent Hill," Duo returned, and Tony had to wonder when they had met. He had straightened, not precisely at attention, but he was definitely on alert. "Miss Noventa," he added with an inclined head. Miss not Agent. There was a story there.

Noventa nodded to him. "Agent Darkside," she said, but there had been the barest hesitation, as if that wasn't how she wanted to address him. "You look well."

"I wasn't aware you had begun working for the ESUN," he replied, crossing his arms. Tony frowned. Tony vaguely knew who Sylvia Noventa was—Pepper would know, he was sure, definitely from money—but he couldn't imagine how Duo knew her. Then again, Quatre Winner was one of his best friends, so maybe they'd met through Winner? Tony had met Noventa in passing at some event or another. Pepper would know more about her. Shame she wasn't on hand to explain the weird tension between her and Duo.

She opened her mouth, but when nothing came out, Hill stepped in, filling the gap so smoothly that if Tony hadn't been watching for it, he'd have missed it.

"We have the first Preventers-Avengers joint assignment for you," she said. She opened a large digital file, and everyone in the room came to attention as she threw up information and images of mobile suits. "This is a probationary assignment. I will be traveling with you, but Agent Darkside will be running point."

That caused a reaction, Tony's among them. Several voices rose to protest, but Duo wasn't paying attention to any of them, focused instead on the videos. Pictures of Tony, Cap, Vision, and Spider-Man floated in the air.

"With due respect—" Cap's voice managed to cut through the rest.

"Do we have suits?" Duo cut in, eyes moving to Hill.

"Why is the team so small?" Natasha demanded.

To Tony's surprise, Duo stepped forward, throwing up the four images. "We're going to be dealing with mobile suits—possibly Mobile Dolls. We need the heavy hitters—Stark, Rogers, Vision, are all obvious, since they are all the strongest physically, as well as the most physically resilient. I'm assuming the same can be said for—Spider-Man, is it?"

"He's not part of this," Tony insisted.

"You made him part of this when you took him to Germany," Hill replied without missing a beat.

"If you need the heavy hitters, why not Hulk?" Bruce asked. "Why not Bucky?"

"Terminator's not cleared because he's still being deprogrammed," Duo said dismissively. "If I need to get in a suit, can the big guy tell the difference between a suit to attack and which not to before he smashes it?" he asked Bruce, glancing away from the video and the information scrolling there to meet Bruce's eyes.

Bruce tapped his glasses in his palm, looking at the video. "I don't know," he admitted.

Duo gave a little shrug. "That's why. Une put this together?" he asked Hill.

Hill didn't startle because she would never do something so mundane, but she seemed surprised by the question. "She did."

"Thought so. Has her touch." He pulled up the map and zoomed in on the area in China they were apparently going to be going. "Do we know what they're looking for with suits?"

"If you need the heavy hitters, Hill, Maxwell shouldn't be going," Cap argued, and Tony would really, really like to stand up for Duo, but he didn't want his son near this either.

"He has expertise with mobile suits and running operations. I have been personally assured by Director Une that she doesn't have anyone on staff she would prefer in his place."

"What expertise?" Cap demanded.

"Mobile suit combat," Duo said, interrupting him. "Can I substitute Terminator for Rogers?" he asked Hill.

"You cannot. Une said if you needed an extra hand, she recommended Maximoff."

Duo was shaking his head. "It's not extra hands we need. No offense, Sabrina, I'm not sure what your magicy stuff will do with suits, and I'm not sure that you can withstand blasts from any weapon that would be equipped to a mobile suit. That's, what, five suits? Do we know how many are in the caves?"

"We're not sure. We've been monitoring the situation, but the suits appear identical."

"Can we even get there before they leave?" Tony asked, and he thought it was relevant. They had time to put this together, and it was in China.

"They're trying not to damage the area. It's Zhangjiajie National Park—if they start banging about and destroying the pillars, they'll bring the whole fucking Chinese military down on their heads," Duo said. He rubbed his forehead. "Do we know what they're looking for?" he asked again.

"If Une knew, she didn't share," Hill said. Tony could tell by the way she thinned her lips that she didn't appreciate being left out of the loop. If he didn't know better, he'd think that Duo knew.

"How bad is it going to be if we bring heavy hitters into that area and start breaking things?" Tony asked because their heavy hitters in an area that the bad guys were being careful in seemed counterintuitive. "And are we sure it's Hydra? I know they've got the logo going…"

"It doesn't matter if it's Hydra. Any unlawful mobile suit activity falls under Preventers purview, and the team is the right call," Duo said with a sigh. "We're just going to have to be very careful. I take it we have a jet coming?" Duo asked Hill.

"On its way as we speak. You're getting a Quinjet—we have a special dispensation. Stark, call Spider-Man and tell him needs to be ready to go in twenty."

"Perfect," Duo said. "I'll go get suited up. Rogers, Stark, you should too."

"What if I just don't call him?" Tony demanded, not willing to just rollover.

Duo stopped, turned and looked at him, looked at Hill, then shrugged. "It's easier with him. I'll make it work without if necessary. You fly, Hill?" he asked.

"I do."

Dammit, that wasn't the reaction Tony expected, but he could tell Duo's head was in full mission mode. He wasn't thinking about what Tony wanted.

"Hold up, kiddo," Tony told him before Duo could head up to his room. "I've got a suit I've been working on for you. And we should bring Wilson."

Both Wilson and Duo seem surprised by that, but Duo was listening, and Tony would take what he could get. "Why Sam?"

"I'd rather Rhodey, but we don't have time to get him here. Wilson is another flier, and I think that could be useful here. It leaves just Cap, Spider-Man, and you on the ground. Spider-Man can do his web-slinging stuff, so he's not really grounded, and Cap can… jump really high, so it pretty much just leaves you."

Duo considered it, then shook his head. "His armor isn't durable enough. One swat of a mobile suit hand, and he's never getting up again."

"That's always a risk," Wilson said, standing up. "I'm willing to do it. And the same is true for you—one stomp, and that'll be it for you, kid."

Duo didn't like it—Tony could tell, but he didn't dislike it enough to justify his own presence to them. "Fine. Three fliers, plus Hill in the Quinjet, three on the ground. That should cover us." He gave Hill a look that was an open challenge, but she just nodded. "Good. Let's get moving, people. We've got air to burn."

Duo met him in the workshop with ten minutes to go. "All right, lay it on me," he said.

"You just got shot, like, a week ago," Tony felt it necessary to point out.

Duo was already pulling his shirt off, and to be fair, only the faintest discoloration remained around where his stitches were—not that Tony was in a mood to be fair. "I heal fast, for the last time. I'm practically good as new. If you're worried, give me whatever spiffy body armor you've got for me, and let me do my job."

Cap was there too, and the sound of the shield locking in place was at once soothing and terrible.

"You shouldn't be going at all," Cap told Duo. "You're the only one other than Hill who isn't enhanced."

"Sam just has fancy tech, and I'm also the only one here who knows a damn thing about fighting mobile suits."

"I'm confident we could figure it out," Cap countered.

Tony just handed Duo the shirt and pants, he pulled on the shirt, barely stepping behind a counter to drop his pants to pull the skin-tight leggings on. He quickly tested the flex and bend of it, but the material was the same that Tony used for Spider-kid's suit, so it would keep him as safe as anything short of an actual set of armor. Tony seriously considered loaning him a suit if he had any that would fit him, and he was still trying to decide if he could grab everything he needed to modify a set in the Quinjet. They'll have probably five hours on the plane. He could modify a suit in five hours, right? Maybe the bigger issue was Duo's learning curve in being able to use it.

Duo gave him a side-eyed glance as he finished getting redressed, then started pulling out sets of knives and sheathes.

"We're going up against mobile suits, remember?" Cap said, and it was about as salty as Tony could remember hearing him.

"Yeah, I know," Duo returned with equal salt, strapping sheathes to upper arms, then forearms with the ease of long habit, checking them without any obvious thought in the action. "I know how to break into a mobile suit cockpit—do you?" He held up a black blade that was nearly as long as his forearm and was the kind of black that seemed to suck light in before loading it in a forearm sheath, then jumping on the table to put more sheaths around each calf before pulling shoes back on. Again, the heavy black combat boots. That done, he pulled out a couple of black leather holsters, and Tony was officially getting uncomfortable with the sheer number of weapons his son was putting on like he wore them every day. Duo pulled on a double shoulder holster first, secured it, then pulled out another double holster, this one went through his belt loops. He pulled out several clip-on pouches and attached them as automatically as he'd done everything else before he finally pulled out four guns. He checked each over with a professional air before it went into a holster.

Tony could feel eyes on him and looked up to meet Cap's look. They both knew this kind of ritual. They'd seen Clint and Natasha go through this prep before, and Cap didn't have to say anything for Tony to know he found it both reassuring and unnerving. Natasha and Clint were veterans with probably twenty years' experience each. Duo was twenty-two, but he suited up like he'd done it for decades.

Wilson walked into the workshop, fully suited up. "Damn. Did you decide to put on every weapon you own?"

The teasing tone eased a little tension from Duo's shoulders. "Please," he said. "We're dealing with suits. This is just in case anyone gets stupid and decides to leave their suits."

"Why don't Preventers have mobile suits?" Tony asked as Duo checked the last gun then holstered it. Every piece on him, from the holsters to sheathes to guns to knives to the clothing was black. Tony was a little relieved when Duo pulled on a Preventers jacked on top, since it, at least, wasn't black. Tony didn't have good associations with people who dressed in such unrelenting darkness.

"We do," Duo said. "But they've all been allocated to space. They're far more effective there anyway. That decision was made after Sokovia, so maybe you missed it."

Tony managed not to flinch at the mention of Sokovia. "What about the Gundams?" he asked.

"What about them?"

"Preventers called them in for Sokovia. Why not this?"

"One—Preventers don't have any dominion over the Gundams. Only their pilots do. Two—this isn't important enough to try to drag a Gundam into."

"But it's important enough to drag in the Avengers?" Cap took the obvious opening.

"Talk and walk, people," Duo said, grabbing his bag and walking over to the elevator. They were forced to follow him. "And yes, actually. Part of what's being worked out in the Accords is how much oversight and support the Avengers will be getting from the World Security Organization as managed by the Earth Sphere United Nations and in partnership with the Preventers. So, basically, this is exactly the sort of thing you would be partnering with us on. And again, the Preventers don't have any dominion over the Gundams. They aren't a Preventer resource."

"But Une knows the pilots," Tony said, because it wasn't a question.

"You'd have to ask her what the difference is between a situation requiring a Gundam and a situation requiring the Avengers is," Duo said getting on the elevator and looking irritated. "To the best of my knowledge, no Gundam has participated in any specific Preventers action since their inauguration. By the way, I don't know why you think I know anything about the Gundams. Everything I've told you is pretty much common knowledge in Preventers. If they're a card she has the ability to play, Une keeps it close to her chest," he said. The elevator opened and they cleared the main floor, stepping out onto the deck just as the Quinjet was landing. Hill fell into step with them as the belly of the craft opened.

Duo whistled. "This is a pretty toy, you've got," he told Hill, pitching his voice to carry over the engines.

"Pretty toy we have now," Hill said. "It's been donated to Preventers for the Avengers joint initiative," she explained. Tony hadn't known that, but it did make sense.

The pilot exited, and whoever the agent was, he knew Duo and made a beeline for him.

"Darkside."

Duo grinned. "Reynard," he said. "I see you actually re-upped your pilot's license."

Reynard tucked his hands in his pockets and shrugged. "Didn't want to be in a position where I might be stuck relying on a crazy partner again." There was a story there, and Tony wanted to know it.

Wilson stepped up beside Duo. "Wait, you're going to fly this thing?" he asked.

Duo threw his head back and laughed. "It has an engine and flies, right? I can pilot it."

"You're sure?" Wilson asked.

"Yeah, Sammy, I'm sure."

Peter swung up and landed somewhere between them and the Quinjet. "I'm here, Mr. Stark. You called?"

"Perfect timing. We have an assignment in China," Tony told him. "Hope you packed."

"Uh, I…"

"If this goes right, we should be back by tomorrow morning, at the latest," Duo said. "If it goes wrong, tomorrow evening."

"Oh, well, that's good. I, uh, would prefer the first, 'cause I kind of have class tomorrow."

Duo stepped toward Peter on his way to the jet and reached up to sling an arm around Peter's neck, which was kind of comical because Peter had at least three inches on him. "C'mon, kid," he said. "Agent Darkside. Let's see if we can get you home in time for class."

Tony followed after as they boarded the Quinjet.

"Not going to give me grief about involving a seventeen-year-old?" Tony asked him.

Letting go of Peter's neck, Duo turned and looked at him. "I was fighting a war when I was younger than he is, and I can't punch a mobile suit. I think it'd be more than a little hypocritical for me to criticize."

"Oh, wait—you're… you're Mr. Stark's son, aren't you?" Peter asked, sounding surprised.

"That's what the DNA says," Duo said, going straight to the cockpit. He dropped the bag in some bungied netting, then took a seat. He barely glanced at the instrumentation as Hill settled in next to him before he began hitting buttons. "Everyone buckle up."

"Are you sure you know how to fly this?" Cap asked as they all got seated and into their safety harnesses. Tony knew from digging into Duo that he had licenses to fly, drive, or otherwise operate any kind of machinery or ship, but it was one thing to know Duo had the licenses and another thing to be confident of him actually controlling something like the Quinjet.

The cargo hatch closed and the engines geared up. Tony felt the Quinjet lift off, then Duo's hand went to the throttle, punching it, throwing them against their restraints. Duo glanced back at Cap. "Looks like," he said, angling the jet higher.

Tony laughed at the dry tone. Cap gave him a Very Disappointed Look ™. "You asked," Tony justified.

Wilson snickered next to him. "You did, Steve," he said.

Maybe Wilson was okay, after all.