Disclaimer: I don't own Marvel or any characters you recognize. I write this purely for my own pleasure.

Part I: Taxonomy

Chapter 1 – Primordial

The Triskelion, Washington D.C.

October 8, 2013

Before waking up in the year 2012, Steve had been to Washington only once before. It was on his domestic tour as Captain America selling war bonds. The cherry blossoms had just begun to wither and fall from the branches. He remembered he was the only one who could smell their saccharine stench—he'd squinted and wrinkled his nose all through his first meeting with President Roosevelt.

He had disliked Washington solely because it wasn't New York. New York streets were dirty and roiling with activity, the buildings blocked out the wide sky, and the people may have been rude but they were New Yorkers. Steve was a New Yorker. Yeah, he got the piss beaten out of him a cool thousand times in the back alleys of Brooklyn, but it was his city.

New York didn't feel like his city anymore.

Maybe New York had changed too much. New York was as much a living breathing thing as any human being and it moved idly on from the war, from him. Seventy years was a long time.

Steve for his part had been away for three years. For three years, home was an S.S.R. bunker. His city shrunk to a group of forty people fighting for a common cause.

Or maybe (and this was the thought he hated to entertain) New York wasn't never his city—maybe it was just the place where he could find the people he loved. But his mother was dead, his friends were dead. Bucky was dead. Peggy lived and lived without him. Howard came later and died sooner.

Now Steve liked Washington because it wasn't New York. Washington was just a place that wasn't familiar and that was all he needed. Steve had quickly learned it was easier to be a man out of time and place than a man just out of time.

After three months of running missions out of the Triskelion, no one blinked twice at the sight of Captain America striding through the atrium in a t-shirt and sweatpants, a duffel bag slung across his body. He checked his watch to make sure he wasn't late to the training session that Nat suggested through text message. He wasn't, though he had no doubt that Nat was already in the gym. She was the only person he knew that was more punctual than he was, even when she'd just gotten back from an assignment.

"You took your time," she said when she heard him come into their regular training room, never ceasing her rapid-fire kicks on a punching bag. "Have you considered getting one of those motorized wheelchairs? A lot of people your age have them."

"Ha, ha," he said sarcastically, dropping his bag in the corner. She made a joke about his age once in the middle of a mission and he'd laughed, so now the jokes were nonstop. He supposed he didn't really mind, though he wondered how differently their friendship would've progressed if he hadn't laughed at that first joke. "How'd the job go?"

She shrugged loosely and took a long pull from her water bottle. "Standard extraction," she said after she swallowed. "Not much opportunity for failure."

Knowing Natasha, it had been far more life-threatening than she let on. He let it go. If she'd been in serious danger, he hoped she would tell him. They weren't very close—not like she was with Barton—but he thought they were getting there.

"No shield," she ordered, capping her bottle and tossing it onto a pile of folded towels.

"No weapons," he added.

Adding that caveat meant that he then had to wait for her while she stripped her body of every knife she'd hidden on it. He didn't know how she hid eight knives in a tank top and work-out pants, but then he didn't know a lot about Natasha. When all her knives were in a pile at her feet, she smirked and asked, "You ready to go or do you need a little more time? I've only been waiting half an hour for you to show up."

He scoffed and got into position. "I'm hearing a lot of talk and seeing no action."

They both held back when they sparred. Steve because he didn't want to hurt Natasha—Natasha because she didn't want to kill Steve. No doubt that in a weaponless, no-holds-barred fight, Natasha would kill him. Armed with his shield, it was a different story.

"Keep telling yourself that," she said when he voiced that thought. Then she threw him onto his back again with little more than a grunt.

She just got back from a mission, Steve thought, groaning as he got to his feet. Shouldn't she be exhausted?

When they go another round, he was quicker. A few jabs, some feints, and she was down—his forearm pinning her to the mat. She was as stoic as ever.

"I'm just tired," she said so seriously, it took Steve a second to realize that she was joking.

"Keep telling yourself that," he quipped back as he helped her to her feet. She smirked. They attacked again.

Neither Steve nor Natasha had it in them to spar for more than an hour that day. Nat waited for Steve as he neatly packed his gear into his duffel. You can take the man out of the army, but you can't take the army out of the man, Nat had said the first time she came to his apartment and seen the Spartan furnishings and neatly folded blankets on his bed. Maybe that was true, but what was truer was that order granted Steve some measure of control over his life.

When he joined Nat, her eyes were fixed on an agent running on one of the many treadmills. She wasn't the only one watching. A quick scan around the room at the other agents surprised Steve. Nearly every one of them was scowling at her, some covertly, others overtly.

The only thing that Steve noticed about the running woman was her hair—long, pulled back into a ponytail; the top half dark, the bottom a bright blue that hurt his eyes even halfway across the gym. Otherwise, she was wholly unremarkable.

He tapped Nat's shoulder. "You ready?"

When they walked past the blue-haired agent, Nat paused and leaned against the treadmill.

"You're doing great," she encouraged softly.

The agent was so startled—whether by the praise or the source or at the sudden appearance of someone at her elbow—that she tripped, catching herself just in time to avoid flying off the belt.

"Agent Romanoff!" she squeaked, pushing her thick-framed glasses up her nose nervously. "Oh, thanks."

"I can kick a few asses, if you'd like," Nat offered. Then she turned and glared at the agent on the next treadmill over, the one openly gawking at the two of them. He immediately turned his face at the blank wall in front of him, eyes wide in fear.

The blue-haired agent laughed. "Aw, that's so sweet," she gushed through heavy pants, her cheeks turning even redder. The offer was anything but sweet. "But I wouldn't be doing this if I couldn't handle a few stares."

What 'this' is, Steve didn't know. But Natasha seemed to understand, smiling once more at the agent before gesturing to Steve to follow her out of the gym. When they entered the atrium, he asked, "What was that about?"

She punched the 'up' arrow on the elevator. "A lot of the scientists are too scared to use the gym because the field agents intimidate them into staying out. It's some stupid S.H.I.E.L.D. thing."

"You're S.H.I.E.L.D.," he pointed out.

She shook her head. "Not like them. It's a rivalry that starts at the academy. Scientists think they're smarter than field agents; field agents think the scientists are undisciplined and everyone thinks they're better than the analysts. I never went to the academy."

She was the infamous assassin for the Russians before Hawkeye brought her in, Steve recalled. The rivalry between divisions was probably quite foreign to her. Steve remembered the rivalry between the branches of military, however, and found it less strange.

"So you were encouraging her. That's…nice of you."

She smiled like she could read his mind. "I'm a nice girl."

"Alright." She punched his arm lightly, giving him a mock-glare. He held his hands up. "Sorry. I emphatically agree."

The elevator doors opened. She stepped in, stopping him from following her in.

"Hey!" he exclaimed. His hand shot out to stop the doors from closing in his face.

She smiled softly at his disgruntled expression. "Go do something fun, Steve. You've been working too hard."

"You're one to talk," he retorted. "When'd you get back, three hours ago?"

"Four," she corrected him without a hint of sheepishness. "But I didn't just take back-to-back assignments."

Unfortunately, that was true. In an effort to spend as little time alone in his apartment in its depressingly unfurnished state, he'd taken three assignments in a row, spanning a month's time and taking him to five countries on three continents. He'd gotten back a week earlier, yet he was already antsy for another job.

When he was silent, she quirked her eyebrow in amusement. "Yeah. You need to decompress."

Now what? he thought as he stood there staring dumbly at the closing elevator doors. The only plans he'd made that day were with Nat. He'd been counting on meeting with Fury to fill up another week, until Nat ordered him to have fun without her. He knew what she had in mind; something "fun" meant going on a date or hanging out with friends.

I need friends first, he thought sullenly.

He wished things were different. He wished he had it in him to go out, socialize, make friends, but the part of him that was afraid of the brave new world couldn't stop missing Bucky and Howard and Peggy long enough to do that.

So he shifted his duffel bag strap on his shoulder and trudged out of the Triskelion, resigned to yet another night alone in his bare apartment.

Dr. Mallory Cohen could take a lot of examination. She didn't like it, but she'd gotten used to it over the years. Being a mutant numbs you to scrutiny.

Of course, no one in S.H.I.E.L.D. knew she was a mutant. In the eight years she'd been working for S.H.I.E.L.D, she'd never revealed her mutation to her superiors. Being a scientist had made her nervous to let her curious coworkers know that she was a genetic anomaly.

Thankfully, her mutation didn't express itself through her skin or her eyes or her hair—which was blue only because she dyed it. Others weren't nearly so lucky. She'd been able to lead a relatively normal life up to this point because she wasn't visibly 'mutant'.

No, this scrutiny was because she was in the wrong place. She could have laughed at how timid the agents were. They all scoffed and rolled their eyes, but not one of them came up to her and told her to leave. Especially not after Agent Romanoff gave her her blessing to be there.

"You're doing a great job," she'd said with a beautiful smile. Mal took a mental picture of that smile and stowed it away to pull out on a rough day.

Unfortunately, Mal had to be a total dork in front of the Black Widow. She stuttered and blushed and almost flew off the treadmill in shock. To her unending credit, Agent Romanoff pretended not to see it.

"Agent Romanoff!" she'd said—in a cool, punk-rock way, she tried to convince herself later—before thanking her graciously.

"I can kick a few asses, if you'd like," she'd offered, shooting deadly glares at the agents ogling nearby.

As a pacifist, Mal was horrified. As a bisexual woman who'd idolized Black Widow the moment she'd first learned of her existence, however, she was very aroused. She'd giggled—again, in a cool, punk-rock way that definitely made Agent Romanoff admire her—and said, "Aw, that's so sweet! But I wouldn't be doing this if I couldn't handle a few stares."

Agent Romanoff had raised a carefully groomed eyebrow and shrugged (Mal later convinced herself that Romanoff was impressed with her blasé attitude and was now resolving to learn her name and phone number). With one final smile that left Mal swooning and nearly flying off the treadmill again, she gestured to the man beside her. In her star-struck awe, Mal failed to notice Steve Rogers—Captain freaking America—waiting patiently for them to finish their conversation.

After they left, Mal was so jittery that she forgot that she was a mutant scientist in a gym full of field agents and turned the speed up to the highest setting. She ran until her muscles were properly tired, exhausted before they could knit back together again, a difficult feat for someone with an accelerated healing factor.

Fifteen minutes later, she stopped off at her office to drop off her sports-bag and pick up her tablet. Then she headed for the laboratory down the hall, humming a jingle under her breath.

"The prodigal daughter returns," Colton said when she floated into the lab. And despite her utter contentment, she rolled her eyes.

"Am I still a member of the team?" she asked sarcastically.

He pretended to consider it. "You'll have to submit another application. Processing takes six to eight weeks."

"You know what, how about I just fire you instead?"

"…Welcome back, boss."

She nodded smugly as he stuck his tongue out at her. Dr. Colton Ford was her research assistant on Project Salamander. And while they'd become good friends since he'd been assigned to her in June, assistants were laughably replaceable. She knew one engineer two floors down who had a new assistant every week. She wasn't sure where the old ones went, but no one ever saw them again. Colton was convinced they were shot and killed and that the cadavers at the SciTech Academy were actually former students who didn't last as assistants.

Colton, the sick bastard, asked, "How was your slog through sweaty, macho hell?"

She sighed exasperatedly. "I don't know what you're imagining, Colt. It's not Fight Club down there. It's really nice. There's a juice bar."

"I don't care if the swimming pool is filled with chocolate—I'm not setting foot in that place."

"That's surprising, considering your diet is mainly Olympic-sized chocolate swimming pools."

"Hey, I had an apple this morning!" When she gave him a blank look, he amended, "I had fruit. Okay, it was Fruit by the Foot."

Another assistant, Dr. Ashley Reardon, piped up sullenly, "It's unfair. You can eat a family-sized bag of Doritos and still be a stick, but if I eat one spoonful of ice cream, I gain five pounds."

Mal sent her a sympathetic smile and reassured her, "Take comfort in the fact that Colt's a deeply unhappy person." To prove her point, he jauntily saluted them with his slide and put his face to the microscope's eyepiece, grinning maniacally all the while.

"Ash, I'd really like a work-out buddy, if you ever want to join me," Mal offered. "Blood circulation is good for brain activity, too. If you're ever stuck on something, an hour of jogging can really do wonders."

Ashley winced. "It's okay. I, erm, don't want to use the gym here. The agents are scary enough when you're not working out right next to them."

Ashley wasn't what Mal would call fat, but she was clearly not in the kind of shape any of the field agents were in. She'd often expressed her desire to start working out, but they were all so busy with work that getting a gym membership would only be a waste of money. And of course, no scientist wanted to use the in-house gym on the bottom floor of the Triskelion because of the stupid rivalry between divisions.

Mal pounded her fist on the table, startling Colton away from his microscope for a second. "Damn those sexy bastards. We can't keep letting these field agents ruin our lives!"

At an adjacent table, Dr. Jennifer Esposito scowled. "Be quiet, Mal," she barked, aggressively signing a tablet one of her interns shakily handed to her. "People are trying to work."

Dr. Esposito was the only other scientist in their lab that headed her own project. She never liked Mal, not from the moment Mal got reassigned from San Francisco to the lab table across from her, and especially not when she got her project approved before Esposito got hers. Mal found her intimidating as all hell.

"Fine, but I'm not letting this go," she said, hoisting herself up onto the table beside Colton.

"Get off the table, Cohen."

"No." She got off the table. "We're not technically banned from the gym, you know. It's just a stupid fake rule."

Esposito glowered at her over her microscope. "Don't you have work to do?"

"I told you; I'm not letting this go."

She rolled her eyes. Mal took this as enough invitation to continue, "No one said anything to me the whole time I was there, Ash. They know they're the assholes."

Ashley nodded and smiled weakly, still not convinced.

"And," she added giddily, "Agent Roma-freakin'-noff told me I was doing a great job. Best day ever? I think so! Gimme some fin, Ford." Ever faithful, Colton slapped her hand when she held it up for a high-five.

Esposito drawled sarcastically, "Wow, Agent Romanoff said that? You two should get married!"

Mal sighed dramatically. "Yeah, if only she wasn't straight, out of my league, and dating Barton." Esposito rolled her eyes.

Ever sweet, Ashley steered them back on course with soft words. "I appreciate it, Mal, but I'm just not ready."

Mal sighed, unable to hide her disappointment. It would've been nice to have someone to work out with, especially considering that it was some of the only personal time she allowed herself. "Alright. But you let me know as soon as you are, okay?" Ashley gave her a weak smile and turned her attention back to her tablet.

Her heart twinged. These days, the sensation was as familiar as her own heartbeat. Mal was not a woman accustomed to loneliness. Xavier's granted its students little privacy, but also little miserable solitude that many mutant children suffered outside of its walls. Mal never had to search far afield for company there. It was the same all throughout her academic career, where she had easily slipped into her niche among fellow biochemistry nerds. She hadn't realized just how much she had relied on the easy companionship academia provided until she left it altogether.

Mal prodded Colton's shoulder, doing her best to hide the desperation in her voice when she asked, "Hey, you wanna hang out tonight?"

He winced and leaned back to look at her. "Oo, can't. Got a hot date with Marlene. Our third date, actually. You know what that means."

"Okay."

"Likely to end—"

"You don't need to elaborate—"

"In intercourse," he finished.

"Colton, that is so unprofessional."

He ignored her protest with a look of rue. "I'm free tomorrow. How about we see a movie and get drinks?" he suggested instead.

She waved him off. "It's fine. I'm working tomorrow night, anyway. The results from the GWAs should be in before then. Another time."

He sighed, running a hand through his sandy blond hair, "You work too hard."

Esposito huffed in annoyance. "Not hard enough," she snapped. "If you're just going keep jabbering, do it outside."

Mal blinked dumbly and shook her head. "Right, I'm gonna work from my office for the rest of the day," she announced to the tabletop. "Colt, get the sequence from LR-C 18 to me before you leave."

"You got it, boss." She caught his worried look before she left the lab.

Even three months after moving into her new office, it was almost bare. It was not for a lack of photos. She had one of her parents in front of their house in Hawaii, and another of her best friends from the SciTech academy, but no others. The ones from her days at Xavier's School for Gifted Youngsters were carefully catalogued in photo albums in her apartment, behind two locked doors. Her mutation was her second most preciously guarded secret. The school was the first.

She slumped into her chair and opened her laptop. There was unread message from Jemma Simmons that lifted some of the pain in her heart. It had to be decrypted before she could access it. Before the girls got reassigned in June, they'd agreed that encrypting their messages was the safest way to stay up to date with one another. SHIELD was, after all, an intelligence agency and it would be naïve of them to think that their messages weren't being monitored.

It only took a few minutes for her decryption program to open the email. Inside, there were a dozen photos—Jemma and Leo making funny faces at the camera in front of an Incan ruin; Jemma and Leo wearing safety glasses making funny faces in their cramped laboratory; Jemma and unfamiliar girl grinning together on a couch. The attached message was lengthy, but Mal drank it up eagerly.

They had only been in the field for three week and already they had been to Peru, Malta, and Sweden. Fitzsimmons came up with a new weapon tentatively named a "Night-Night Gun"—Jemma asked Mal to brainstorm a better name—and were working on derivative weapons like small gas bombs. Mal was happy (and jealous) to hear that they'd snapped up a quick and easy friendship with the girl in the photos, who was named Skye. Still smiling fondly, Mal read down to the end of the note—

I've got to go now, we're taking off. Fitz says hello. And Skye's been reading over my shoulder; she says hello as well. We miss you terribly! Write back soon!

Love, Jemma

P.S. I know you're working too hard. Get out and do something fun!

She rested her face in her hand. Fitz had always been content with puttering around a lab, but from the moment they met, she knew Jemma would never be satisfied with that. She had an adventurous spirit, just as Mal did. If she wasn't so intent on her project, she would've requested a transfer to the field with them.

She snorted at Jemma's hopeful post-script. Fun, she thought, gazing at her old friends' smiling faces. No one wants to have fun here, Jem.

And instead of going home like she'd planned, she stayed at work until early into the morning.

This is a bit of a crossover story between Captain America: The Winter Soldier, The Avengers, the X-Men franchise, and Agents of S.H.I.E.L.D. Most accurately, it should be in the Captain America section because Cap is the main canon character and because the beginning takes place from October to CA:TWS. After that, there will be more appearances from the X-Men and the Avengers, but the focus will still be on characters from TWS.

I try to reply to every review I can, so if you have any questions, comments, concerns, let me know and I'll get back to you ASAP!

Edited August 2021