Disclaimer: I don't own anything.

A/N: This is my first Avengers fic so I'm extremely nervous about posting it. It's just a really weird idea I got one day and decided to run with it, because, why not? I know it's far-fetched and requires a ton of suspension of disbelief, but I hope it's at least enjoyable if not entertaining. Special thanks to my friend Olivia for reading this over, giving advice, and encouraging me to write it down. Let me know what you think!

Chapter One

Rain droplets made their winding descent down the floor-to-ceiling windowpanes of Stark Tower as New York City was doused in a generous afternoon summer storm. Thin fog rose above the metropolitan landscape, skyscrapers peeking through the haze. Eyebrows knit together, Steve watched the rain fall with his hands planted on his hips.

"So, you're really not going to tell us what Stark and Banner are up to?"

Behind him, Natasha gave an annoyed sigh. She was lounging on the couch with her legs across Clint's lap. "For the last time, I told you their nerdy science project is classified. I'm sworn to secrecy."

"It's been months." Steve turned around, exasperated, throwing his hands in the air. Natasha rolled her eyes. She found Rogers' melodramatic diva moods more than irritating. Clint, who had his gaze fixed on the TV engrossed in a video game, enjoyed Natasha and Steve's epic bitch-offs.

"Whatever the hell they're working on, they can damn well share with the class. We're supposed to be a team."

"I am not in the mood for your afterschool special, Mister Rogers," Natasha said. "Leave the geeks in their natural habitat. They haven't broken anything."

"Yet," Steve countered. "How come you get to know the big secrets while the rest of sit here twiddling our thumbs?"

Clint let out a barely suppressed snort at Steve's turn of phrase, to which Steve fixed him with a hard stare. Clint didn't see it, but he could practically feel the glacial frown smack him in the side of the face. He guessed it might have been due to the fact that he had a habit of calling Steve "gramps," and "old man." But to be fair, Steve was always dishing out old timey lectures and couldn't work a single piece of technology in Stark Tower without assistance or written directions to save his life. There were brightly colored Post-It notes stuck onto kitchen appliances and electronics in Pepper's neat handwriting as proof. At least Thor thought they were helpful.

"That information is also classified."

"Remember who you're talking to, Cap," Clint advised.

Steve all but bit his tongue and pivoted on a heel to continue glaring daggers out the window. Tony and Bruce's latest endeavor was grating on his last nerve. He recalled a discussion full of jazzy science lingo and something about experimentation with their team's extraordinary genetics. Before Steve knew what was going on, he had a 21st Century-induced headache, and they had hunkered down in the lab.

Months later, a little supposedly "harmless" testing had turned into full-blown scientific hibernation. The lab became off-limits and hermetically sealed. Tony and Bruce emerged for basic human necessities, although Clint had started to question the last time they had taken a proper shower. The notion of shaving had been thrown out the window long ago and Bruce was beginning to resemble a Discovery Channel survivalist reality star. (According to Thor, who watched too much television for his own good.) Coffee was consumed at such an alarming rate these days that Natasha was certain Banner and Stark had found a way to replace their blood with straight-up caffeine. Meals were silent, awkward, and tense—reminiscent of their first dinner as a group. Thor watched in quiet awe (Loki in pure mortification and absolute disgust) while Tony and Bruce shoveled down their food faster than they could breathe. Neither one offered up any progress about their work and shuffled off down to their science lair like zombies. Pepper had made the mistake of asking and was treated with a few sharp grumbles and the fiercest Stark bitchface she had seen yet.

Garnering information was useless unless you happened to be Natasha Romanoff, who had been summoned down to the lab early on in their scientific shenanigans. She returned looking paler than usual and a little stunned. Steve had kept bothering her ever since, unconvinced that what Tony and Bruce were slaving over was as harmless as they claimed it to be. Those arguments never ended well. Typically, if the fights escalated, the resolution came in the form of demolished furniture, new bruises, and Thor pulling them apart. (While Clint laughed and Loki pinched the bridge of his nose in frustration.) He should have known better by now, but the whole situation at hand was trying everyone's already thin patience.

"So, any word from our favorite science bros?" Pepper's voice echoed along with her heels against the floor. "Everyone still in one piece? Furniture mostly intact?"

Pepper took their relative silence as an affirmative to the latter questions. Steve watched her descend the steps and drop several paper bags on the center table. It was the first time Clint had torn his eyes away from the video game.

"Haven't seen them since their last coffee break," Natasha glanced at the clock, "which was about seven hours ago."

"Sounds about right," Pepper said. "I brought Chinese takeout."

Clint was the first to make a move for the piping hot bags of food, pushing Natasha's legs off his lap and dropping the game controller in rapid succession. Thor, who had the uncanny ability to pick up on the aroma of food from an impressive radius anywhere in the tower, was heard stomping down a nearby hall. It was always a betting game to see whether Loki would show up for dinner or one of them would have to leave the food outside his door. (Which was decided by an aggressive straw pull.) Today felt like a no-show, but the team was surprised when he sidled into the room wearing his ever-present scowl.

They settled into their painfully awkward eating rituals, sprawled across couches and chairs in the living room with cartons overflowing with lo mein, sweet and sour chicken, fried rice, and assorted other dishes spread over tables and laps. Steve couldn't hide his smirk while Thor struggled with the chopsticks (as usual) and splintered both of them into pieces in his bear claw-like hands. When he thought no one was looking—but everyone was—he chose to tip the carton of noodles into his mouth instead. Clint choked on a spoonful of fried rice and Natasha had to smack him in the center of the back. Loki almost looked thankful when Pepper cut through the tension by clearing her throat.

"Do you think there's any hope of luring them out with food?" she asked.

"I wouldn't press your luck," Steve answered. At least her tone of irritation matched his. He was gaining an ally. Or so he hoped.

"You're right," she laughed. "Even if they took the bait I'd probably lose a few fingers."

"They must appear eventually," Thor offered.

"That's what we said that one week, remember? They didn't eat at all." Clint spoke around a mouthful of General Tso's chicken.

"And you were convinced they were living off freeze-dried meals and astronaut ice cream," Natasha said.

"That wouldn't surprise me." Pepper said with a shake of her head. "Well, if food isn't enticing enough, I say we stage a protest."

"Finally, someone who speaks some sense," Steve said, as if the sunlight had at long last broken through the dreary weather.

"Wouldn't it be easier if Thor and Cap broke down the door?" Natasha suggested.

"It would, but you know how Tony gets when people ruin his stuff," Pepper replied. "And the lab is like hallowed ground."

The group lapsed into a lull, replaced with the light pitter-patter of rain against the windows, before Steve leapt up from his seat. Determination was set into his face. He wasn't going to stand for this secretive business for much longer. With a grin, Thor followed suit, spilling the last of his sweet and sour chicken in his rush. One by one, they tore themselves away from the remnants of their meal (Loki rounding out the group with his arms crossed defiantly over his chest). They piled into the elevator for a short but uncomfortable trip. Those close quarters were never enough to house the sheer amount of muscle between them all without at least one of them getting agitated. Namely Loki, who spent the duration of the ride pressed as far into the corner as he could manage without cutting dents into the wall with his bony elbows.

The lab spanned the entirety of the floor, but the plate-glass entrance to the gigantic workspace had been boarded up and covered with sheets from the inside. It looked absolutely ridiculous; a cross between a questionable demolition site and a hazmat situation. Neither one of them could hear a sound from the inside, which left the floor in a state of eerie calm. Natasha resigned herself to the current circumstances and leaned against the wall, deeming their efforts pointless. Pepper instructed JARVIS to tell Tony and Bruce that their disgruntled teammates wanted a word with them, although Steve and Loki appeared to be disgruntled enough for the six of them and then some.

Clint stared forlornly at the closed elevator doors as if he was still thinking about the half-eaten takeout they had abandoned upstairs. It was something to distract him from the steadily growing cloud of anger that was forming over Steve's head. Thor was contemplating Natasha's prior suggestion to rip the door from its hinges or punch a hole in the plywood-sheet combination barrier just to quell his curiosity. They waited, impatient, for any signs of movement from the lab. Minutes ticked by and the aggravation started to swell into the very beginnings of concealed rage. It seemed like everyone was finally getting to Steve's level of frustration. Pepper tapped her foot against the floor—used to Tony's penchant for taking his sweet ass time to do anything at the request of another person—and made a move to knock on the barricaded entrance.

A haggard, bleary-eyed Tony slipped out of the lab and shut the door behind him. After raking a hand through his hair, he regarded the group, his facial hair nearly seared off from the amount of rage Steve was emitting alone. If Steve's eyebrows pulled together he was sure the guy would bust a vein. Tony threw his hands up in front of him in a show of surrender, afraid that he'd be pounced on at a moment's notice. Steve looked about ready to, and so did Pepper.

"Want to tell us what you two have been keeping a secret, or are you going to just let this continue and see how long we can go without breaking in ourselves?" he demanded.

Tony bit back a smartass remark and sighed. "All right. Here's the deal. Now," he said slowly, "don't freak out."

Pepper buried her face in her palm. "That preamble is never a good sign."

Clint and Thor exchanged concerned glances behind Natasha's back. Steve crossed his arms over his broad chest. Loki pretended to be more interested in the cracks in the floor than anything Stark had to say, ever.

"Just," he continued in his cautious tone, "a fair warning. Y'know. Before the claws come out and you take turns ripping me to shreds."

"Get on with it, Stark," Natasha told him.

There was a moment's hesitation before Tony knocked on the lab door. The mood in the hallway shifted in an instant as everyone waited on bated breath for proof of whatever groundbreaking project the two of them had been devoting their round-the-clock efforts to these past several months. Bruce emerged, freshly shaven but still sleep deprived and unkempt. Mouths dropped, speechless, in a mix of abject confusion and a range emotion that could not be described in coherent sentences. He had an infant—by estimation, several months in age; undeniably not a newborn child—cradled in his arms as if he was terribly afraid he would break it at any given second. Bruce's steps were wary, but his expressive brown eyes were filled with such a doting father look it was distracting from the overall situation. Puzzled was an understatement. Mild concern didn't even come close.

Tony thought he heard a chorus of crickets for the duration of more unbearably awkward silence. The team traded glances; first at Bruce and the infant, then at Natasha, who, despite being in on the whole project, seemed to be in the same state of utter shock. Pepper made a noise like she was going to say something and then stopped. Clint held a blatant stare at Natasha with amusement in a ghost of a smirk. The question to end all questions circulating around everyone's mind was what Pepper finally managed to ask.

"What the hell were you two doing in there?"

"Honestly, it's not what it looks like," was Tony's response.

"Oh, really? Then you might want to explain yourself." She had to turn away from him for fear of delivering a punch to his face. "I always knew you morons would find a way to procreate with your freak nerd brains." She pushed her fingers into her forehead like she was massaging away a headache. "This cannot be happening right now."

Steve made the effort to pick his jaw up off the floor. "I don't know what stunt you're trying to pull here, but this…this…is what you call a harmless experiment?" He turned around quickly to face Natasha. "And you knew about it?"

"I didn't think it would actually work," Natasha replied, voice rising. "Although, with their track record I should have given them a little more credit."

"Damn straight," Tony agreed.

Pepper shot him a steely frown. "Still waiting for that explanation, boys."

The baby cooed and wrapped one pudgy hand around Bruce's index finger. "We spent a few days analyzing DNA samples from everyone on the team. We had an idea to pull the most desirable traits from each person and recombine them in a non-conflicting code—"

"In English," Steve groaned.

Tony gave a Vanna White-esque gesture to the gurgling baby. "She's a genetically engineered life form made up of DNA from our super group. Get your minds out of the gutter."

"You agreed to this?" Steve asked Natasha, who shrugged.

"It's clearly one of those 'it seemed like a good idea at the time' failures in judgment," Natasha stated.

"Why?" Pepper asked. She was itching to smack Tony in the face, Steve could tell. "Don't tell me you got bored."

Bruce sought out Tony, who obviously did not have a decent explanation for any of this. Clint couldn't stifle his rather unattractive snort.

"So, you guys just figured, 'what the hell, let's grow a baby' and satisfied your nerd boner with a scientific one night stand?"

No one seemed to know whether or not to laugh or start a fight. Thor observed the banter, one hand on his chin as if he was trying really hard to work out what exactly had happened. Based on what few Norse myths Natasha had read, she could guess that he (and, well, Loki—though she'd rather forget the myths she saw on him) was used to much more oddball occurrences beyond two idiot scientists growing a superhuman in a lab. If, of course, those myths held truth. Still, Loki appeared wide-eyed and on the verge of banging his head against the nearest wall.

"This is why we don't do science while drunk," Pepper declared.

"I don't know." Clint was the first to step forward and study the infant. He was still wearing an amused grin. "I think it's kind of cute." He hovered over the baby wrapped in an oversized blanket, taking in its soft, dark brunette curls and wide blue eyes.

"She," Bruce muttered for clarification. He'd twitched somewhat every time the infant was referred to as 'it.'

"She better be cute. I mean, with the collective gene pool she came out of…" Tony started, proud of himself.

"Unbelievable." Steve rolled his eyes.

"I must agree with Agent Barton," Thor cut in. "This tiny human is quite…adorable."

Loki was revolted. "If this is how you mortals make use of your spare time, I think I have vastly underestimated your stupidity."

Steve was temporarily bewildered considering it was the first time he had agreed with Loki on anything.

"You do understand we're responsible for her, right?" Natasha asked. "She's not just one of your dumbass robots."

"We get that," Bruce defended. "We've been doing our best while monitoring her progress in the lab."

And now Pepper understood the odd boxes sent straight to the lab before she could intercept them; filled with diapers, baby formula, clothing…items that would alert anyone's suspicions to their work.

This is the last thing she would have expected. Pepper had so many other questions, she didn't know where to begin or whether she wanted the answers. The only mantra her racing mind latched onto was, what the actual fuck.

"Parenting's not exactly my forte," Tony said. "Bruce, on the other hand, is a natural."

"Fantastic…well, way to put forethought into this, gentlemen," Pepper said. "Do you have a plan?"

"We have to take care of her," Steve decided. "There's no other way around it."

As usual, they were left dealing with the consequences of the science bros' joint ventures in experimentation. Outlandish technology with creepy levels of artificial intelligence were all too common in the Tower. Creating infants with super abilities were not.

Bruce handed the baby off to Clint, and the separation anxiety was visible. He held her securely against his shoulder, her fingers grasping at his shirt. Her mouth was open, drool trickling down onto the fabric. She was studying everyone for the first time, babbling and smacking her gums. Clint was amazingly at ease. It was strange for them to see a master assassin rocking back and forth on his heels with a baby in his arms. And he was oddly attached already.

"Fury's going to love this," Natasha said.

The communal "oh, shit," moment that followed was practically tangible.

"Mr. Personality? You kidding? He's going to adore Frankenvenger." Tony answered.

"You did not," Pepper groaned.

"Yeah, he did," Bruce said with tired sigh. According to his tone, the atrocious term of endearment had stuck around for awhile.

"It's a name that's as cool as it sounds," he protested. "Like a…'70s heavy metal band or something."

"All right, I guess I'm going baby supply shopping before I knock Tony's teeth out."

And with that, Pepper disappeared into the elevator. Not that anyone could blame her; Tony was bearable in small doses and this was just too weird to begin with. Everyone except Tony came to an agreement that the outrageous nickname was not going to stay and retreated upstairs with their newest addition in tow to figure out their game plan on how to handle this turn of events. It was in the second uncomfortable elevator ride of the evening that Stark decided to break the ice with an addendum:

"This would probably be a bad time to mention Rock of Ages' genetic material slipped in there, too, wouldn't it?"

Whatever color was in Loki's face immediately drained as the elevator occupants staged a verbal mutiny against Stark. Everyone shuffled off to the living room, grumbling, to distance themselves from the science bros (though Clint had taken the baby with him). Bruce shook his head, removed his glasses, and pinched the bridge of his nose.

"That went well."

"Oh, I was picturing worse," Tony said. "The Tower's still standing."