Maybe the problem had been boiling beneath the surface for a while, because after one small comment the argument had escalated with terrifying speed.

In a moment where he stood watching the fabric of the Avengers being tenuously knitted back together, Peter commented, almost to himself, he might not have been so enthusiastic in Germany if he'd known T'Challa really meant to kill Barnes. The fight at the Leipzig airport had actually been kind of fun, the more so because he'd been reasonably sure they were only fighting to incapacitate. He had gotten fairly good at telling when someone was genuinely trying to kill him.

He liked T'Challa, who carried a dignity that (sometimes) sobered Peter's motormouth antics. He had said it because he, too, understood grief and the knee-jerk hate born from it. Killing Barnes would have been a stain that never left the king's soul, Peter knew, and he was inwardly grateful that he didn't end up a party to it. And the death would have been ever the chasm between the Avengers, preventing their truly reconciling.

Mr. Stark's reaction was unexpected.

"And who are you to decide that?" he said sharply, taking Peter aback.

"What?"

Stark's face plate had receded along with the imminent danger, and in the day's waning light Peter clearly saw his frown. "Just because you tapped into the fight, kid, doesn't mean you know the half of it."

Defensively, Peter raised his eyebrows and said, "Well, it would have been nice to know before I got roped in as an accessory to attempted murder."

"T'Challa's father was murdered," said Stark—did he know he was clenching his fist?—"and T'Challa retaliated."

"Barnes didn't kill his father," Peter replied incredulously. What was with him? "T'Challa would have killed an innocent man." Peter so feared taking a life that he had great pity for Barnes, whose choice in the matter had been taken away for so long.

"He is so far from innocent," said Stark.

Peter didn't get it, stepping back and feeling like he'd missed a question on the pop quiz. Why was Mr. Stark wound so tight now when it came to the sergeant? Before Germany he hadn't appeared to care personally about Barnes one way or another; his main concern had been reserved for the wayward Steve Rogers. The Winter Soldier had barely factored into his lectures. Peter didn't even know about that awesome metal arm til Barnes had thrown a fist at him.

Things had changed after he'd landed back in Queens. Something had happened in Siberia and now Stark refused to even glance in Barnes's general direction. The soldier stood there now, and the new arm he bore courtesy of T'Challa—who had tried so fiercely to kill him—shone dully in the red light. Some distance away the other Avengers had begun to look over curiously, though they were out of earshot. It should have been an idyllic scene, the group of them together with a sun setting behind them, but Peter was barely aware of them.

He didn't say anything, hoping to drop it, but Stark wasn't done. "What do you know about revenge?" There was a shake in his voice Peter had never heard before.

Did the guy really think Peter was such a kid? He flushed and said, "I know what murder is—"

"You really don't."

Glancing self-consciously at his teammates, Peter edged away from them. Bewilderment was giving way to irritation. How was the other man taking this as a personal attack? Never before had he reacted in this way to something so insignificant, and Peter had the feeling he'd stepped on a landmine meant for someone else.

Vaguely he felt the instinct to back down, to make peace, yet he couldn't help but say edgily, "Why? Do I have to be eighteen or over to know? Because this sounds like something that should go on my driver's license, next to my birth date and whether I'm an organ donor—"

"The sarcasm is not helpful right now," said Stark, he who was always sarcastic.

"Is that something else you get to decide?" muttered Peter.

Stark's eyes flashed. "There are a lot of things you don't understand about the world and this is one of them. High schoolers don't get to judge; Mock Trial Club doesn't count. Put that on your driver's license."

Peter wasn't about to trot out Uncle Ben for him. But for the first time since Tony Stark showed up on Peter's couch sitting a little too close to May Parker, Peter found himself getting genuinely mad at the billionaire.

"Something bothering you, Mr. Stark?" he deadpanned.

"Yeah, something's wrong with the stereo in my suit," snapped Stark, tapping where his helmet still covered the sides of his head. "I keep hearing this high-pitched whine in my ear."

A fierce blush crept up under Peter's collar, and he was glad for the mask hiding his red ears. Sensing the heat rising in his face, his suit deployed a cooling system with a small but embarrassingly audible hiss.

"Woah, fine," he said, raising his hands and starting to back away toward the others. "Forget it." Let Stark bitch to empty air, Peter wasn't going to stick around for it.

"Extra credit for the latchkey kid," Stark said as a parting shot.

What? Peter spun. "The hell does that mean?"

Possibly Stark realized that his words could have been misinterpreted as a dig at Peter's situation as an orphan, because too late, he tried to backpedal. "I didn't mean it that way," he muttered.

"No shit," said Peter, but it was still a shot at his age, among the many already made. He was getting sick of it, and maybe he was a little touchier about it since most of the Avengers had taken up the joke, save for Rogers and Banner. Barnes didn't take up jokes.

He knew his place, okay? At best, he'd so far been the cavalry. And yeah, he was a teenager. Fine. So what? So he was expected to just go along with everything he was told to do? No doubts, no reservations about consequences? Just what, be grateful they were including him? Letting him tag along?

That's when Peter blurted out the thing he'd never intended to bring up to Stark, ever. "Okay, so, life-and-death stuff isn't a choice you get to make for other people, right?" he demanded. "That's your great wisdom here?"

"Right," said Tony testily.

"Then what was with that kill mode you put in my suit?"

Not expecting him to lobb that after dodging the issue for so long, Stark looked warier, and a little like he'd regretted losing his temper. Yet he didn't back down, and upon seeing his expression harden stubbornly Peter got even more incensed. "Yeah, I know about the kill mode," he said, flaring, "One of your training wheels fell off."

"You crashed the bike," Stark spat right back.

Their voices had raised slightly, the tone if not the exact words carrying faintly across the way. Tactfully, Captain America turned and walked in a different direction, ostensibly saying something about securing the perimeter. The perimeter was hardly in jeopardy but Wilson and the Winter Soldier followed, and then some of the others went a heartbeat later peering over their shoulders all the while. Romanov found a pile of rubble to lean back against and crossed her arms, away from the conversation but unobtrusively observant. Peter hardly noticed.

"I was preparing for the future, okay?" said Stark.

Really, like the kind he talked about 'reframing' in his half-assed speeches to the September Foundation? Gears in Stark's metal armor whined slightly as he shifted his weight to stare at the patch of ground the Avengers had vacated.

"The future?" Peter said flatly. "I thought that meant getting in a good word for me at MIT. Not killing. How exactly do you plan that for a kid you just met? Oh, my God," he said, rocking back with a flash of comprehension, "that was already in the suit in Germany, wasn't it?"

Of course it was. How had he not thought of that before? For a heartbeat he hoped it'd been a later upgrade to the suit, something added after he'd proven himself at the airport. A fractional hesitation was the only answer from Stark he needed, and Peter was too aghast to care what he said next.

"Oh, God. How long did you think it'd take for me to use that? What—how—" he spluttered, shrilly "—at what point were you going to decide, 'hey, it's time for him to go Terminator?' Is that what 'training wheels' are," he flapped his arms around, "moral hangups you were just waiting to like, fall off?"

"More like naivety," snapped Stark. When Peter shook his head insistently and turned away, Stark practically shouted at his back. "What the fuck did you think, that you could just web up someone like Loki? Like Thanos? Maybe I didn't want to leave you in the wind, you ungrateful brat. You're not going to just take down bicycle thieves forever, there are bigger fish to fry and I wanted to make sure you could actually fry them. Instead," he jabbed a metal finger toward the irate teenager, who'd wheeled around for a retort, "you take asinine risks and about get yourself killed to try and save people who just tried to take off your head when you should be aiming for theirs."

He was not only referring to Toomes, which might have been forgivable had it been a onetime thing. It hadn't been. Peter stood with taut fists, too shakingly furious to heed the horror in the back of his head at this intensifying blowup with his longtime idol, the guy who'd set Peter up as a legitimate hero in the first place. At the same time, though…just how long was Peter supposed to be cowed by gratitude?

Deep down he knew these ugly words on both sides were sparked by the incendiary factors of exhaustion, fear, and near-constant fighting over the last few days. Everyone was tired and irritable and rather than coming as a comfort, their first few hours of real peace only served to exorcise the pent-up stress. Then the wrong button had gotten pushed at the wrong time.

His angry speechlessness broke when Stark turned away.

"I'm not your son."

Stark rounded as his face went white. With shock or fury, Peter couldn't tell.

"I'm your teammate. Right?" pressed Peter. He stared at the frozen Avenger and repeated, with a pleading note that the animosity couldn't hide: "Right?"

Tony Stark said nothing.

"I know you feel responsible," said Peter, suddenly desperate, "but you can't think of me as like—like a surrogate kid and respect me as an equal. I don't need a dad. I need help, and you need me. Either I'm just a kid or…or I'm one of you guys."

There it was, in so many words. So long as Peter was just a boy to them, he'd never truly be an Avenger. It wasn't so much that he wanted to be one of them, though he did—with all his heart—but that he had to be one of them, for their sake too. The world was too small and the galaxy was too big to shut him out. They were partners, all of them. Comrades in arms.

Despite losing both parents to a plane crash at four, Peter had not lacked for a father figure. He'd had one until the year before, when that figure was cut down one average night in a shock of blood and horror. It was one of those private, life-shattering tragedies that clocked somewhere below the mass slaughter usually in the Avengers' field of vision, the kind of thing that only Peter seemed to be working daily to stop.

The Avengers had never represented the fork in Peter's road; the two paths had lain in the wild-eyed face of Ben Parker's murderer. There, Peter had chosen one road and he chose it forever. In death, Uncle Ben had imparted his most important lesson, and it would not be superseded by anything Tony Stark had to say.

Which was very little, now. The moment had stalled, Peter spiraling down from the peak of anger to a place of dawning alarm and embarrassment now that the tides had receded from the shore.

Accepting that he'd cooled down, his suit switched off the AC. For the first time he realized Karen had stayed silent throughout the argument.

He'd known from little asides that Stark had had issues with his own father, and Peter had never wanted to step in the way of whatever psychological progress the man was making. He felt guilty for doing it now. However mad he was, he really did not want to hurt Mr. Stark's feelings.

"So um," Peter sighed, wishing Stark would say something, "if I'm gonna be a partner, you guys have to trust me or it's not fair. And you have to listen when I say…I will not kill anyone."

He thought maybe he owed an explanation, because this was something that was unofficially sort of in the job description, so he hesitated before going on to say what he'd never told anyone. Forcibly ignoring the magnetic resistance he had to looking Stark in the eye, he admitted: "I'm afraid of killing. I'm afraid of it happening once, and I'm even more afraid of not being so scared of it the second time. There can't be a second time if there's not a first. And, yeah, I'm too young to be ready for that anyway, but I am never going to be ready for it."

Overhead, Wilson took flight. He soared over to the purpling sky to scout, his amazing wings sounding like a distant airplane.

Gazing after him, Peter murmured, "I used to think maybe you all would see me as a burden if I didn't do it, but I don't think that anymore. I'm not a liability. I think I'm the reminder you guys need. Because I think maybe…you've forgotten how to be afraid of the right things."

He realized as he said it that the Peter Parker who could use the kill mode to its full, terrible effect was not the Peter Parker they needed. Who they needed was the enthusiastic, optimistic, happy-go-lucky guy who loved his aunt and his friends and his neighborhood, who loved helping people find the train station and getting their bikes back. Who could say, with earnestness and complete faith, that mercy was strength. Peter needed him too.

Behind them the sun was disappearing with a last gasp of light. Now that the veneer of adventure had faded somewhat he found himself homesick in this strange place and missing Aunt May and Ned, who assumed the likeness of bright tethers in his mind that kept him close to reality, in Queens.

At last, Mr. Stark seemed to sag. It was another full minute before he spoke. When he did, the anger was gone and he sounded, for the first time, a little sad and unsure.

"Okay."

Okay? Okay as in…Peter was still an Avenger? Or okay as in, You're done, pack your suit?

With a sideways look for Natasha, who had begun to move away in truth, the older man went on slowly, "Listen, k—Peter. The only thing I said to you just now that wasn't complete bullshit…was that you don't know the whole story."

Peter waited.

"And—" here Stark rubbed his temples— "it's not because you're a kid. It's because I'm an asshole who can't let go of the past." He stared at something Peter could not see.

The teenager wasn't sure what to make of this flash of vulnerability, which happened so rarely. His hand snaked nervously behind his back to pluck at the spider emblem there.

"Don't do that, you'll pill the fabric. The truth is…well, I'm gonna keep that private. I have a problem with Barnes and it's not going away anytime soon. But—" He sighed. "I shouldn't have taken it out on you. I'm sorry. And maybe you're right. About your right to be ah, a conscientious objector." He kind of rolled his eyes at the end, and with relief Peter felt normalcy settling back in.

"Thanks." He meant it.

They lingered awkwardly there, but Peter was secretly relieved by the confrontation he didn't think he'd ever make were he not as exhausted and banged up as the rest of them.

It felt like the first open confirmation that Peter was truly an Avenger, for better or worse. Spider-Man took the same risks they did, made greater for the identity he was determined to protect, and shared in the challenges as well as the brief moments of brevity. He may not even have to sign the Accords, which were not designed for galactic considerations and were rapidly falling apart. He felt optimistic, and smiled beneath his mask.

"Is this a bad time to admit the programming for your new suit was code-named 'Growing Pains?'"

"Oh, my God, Mr. Stark," said Peter, throwing up his hands in disgust.

Mr. Stark laughed.

.

.

This is a distant cousin to another one-shot I wrote called 'Trust Falls,' where Peter worries about his place on the Avengers.