A/N: I'm loving how much you guys love this! I didn't think it was that great but the feedback has been phenomenal! I apologize for the wait, it takes me a few days to write, revise, and add parts to it. I use an app called Reedy to listen to my unfinished chapters and then go back and edit them. But don't worry, I am still working hard to get the chapters out! ALSO please check out a video called "Somewhere" by blueincandescence on YouTube. Absolutely beautiful video where I got this song from, inspired by an amazing fanfic also found on this site called A Place on Earth by Katla, about Bruce and Natasha running off together. One of my absolute favorite fics of all time! Check it out! Oh, and enjoy!

Partially inspired by: Somewhere by Sanders Bohlke

The atmosphere in the lab felt thick as cement as Steve leaned his shield against the wall near the door. Bruce swallowed, muttering a soft 'oh…' as he turned towards the display behind him to avoid staring at the irritable super soldier at the door. Tony coughed, running a hand through his hair as he blew out a long breath, turning away to ball up some random sheet of paper and toss it in the trash halfway across the lab. Natasha raised an eyebrow at him, watching the paper bounce off of the edge of the can and drop to the floor.

They were silent for a while, the only sounds being the gentle rustling of Bruce trying to find some kind of paperwork that would distract him and the sound of Tony's uncomfortable sniffling. Natasha just stared at Steve, who stared back as if daring her to try and refute what he just heard. Only Tony seemed to be capable of speaking after a few tense moments.

"Nice of you to drop by, Cap. Most people would knock, or call or…" he shrugged, waving a hand over one of the many holographic screens to minimize the one showing all the articles. "Maybe those manners are too modern for you."

"Your walls aren't as thick as you thought they were, Stark. And I'm not up for your games." Steve said, getting right to the point as he stepped into the lab, decked out in his full Captain America gear.

"Aw, and to think I was just about to whip out Yahtzee." Tony frowned, his eyes twinkling with bitter laughter as he spun on his heel to try tossing another wadded up paper into the trash.

"Stark." Steve said stiffly as Tony missed the can again. "Is HYDRA trying to recreate me?"

"Well, yes...but before we get to that, I also have a question." Tony raised an eyebrow as he turned back around, crossing his arms. "Where have you been, young man? Was Cap making a public appearance at some kid's late-night birthday party?"

Steve narrowed his eyes, staring Tony down before he spoke, removing his helmet and tossing it next to his shield. A soft resounding clang floated through the lab as his helmet thunked against it. Steve's mind was absolutely reeling at the idea of an army of super soldiers, but knew he wouldn't get straight answers from Tony just yet because...well, he was Tony.

"I had business to take care of."

"What a wonderfully vague response." Tony smirked. "That explains why you didn't get any of the data Romanoff sent in."

A moment passed, Tony giving Steve a questioning look, who simply glared back, waiting.

"Tell Rogers what he needs to know, Banner." Natasha almost demanded, her eyes not leaving Steve's face. Her sudden tight, professional tone was simply a mask, hiding the apprehensive tension she felt coursing through her veins.

Bruce jumped a bit at the sound of her voice breaking the silence, clearing his throat before he adjusted his glasses and gestured for Steve to join him in front of one of the screens. Of course it had to be him to break the news. It was always him.

"I would hope I need to know everything since it's about me." Steve muttered, passing Natasha to join Bruce.

Natasha watched Bruce gently explain the situation to him, watching Steve's brows furrow in irritation and concern. She had always been good at reading people. It was a requirement for being a decent assassin… but Steve was never the most open man in the world. She supposed losing as much as he had would have had some kind of emotional effect on him. And yet... ever since she'd worked side by side with him all those years ago, and fought at his side as part of the Avengers, she'd gotten pretty good at reading him, even with his usually closed-off nature.

Saying that he was 'upset' by what HYDRA wanted to do was probably the understatement of the year. Steve was livid.

Bruce had been right, he was taking it all very personally, as if he had simply handed the super serum over to HYDRA with a 'welcome to the family' card attached. Which was, of course, absolutely incorrect. But if the tight set of his jaw as he silently scooped up his shield and helmet before exiting the lab was any indication, no amount of talking would change his mind. So they let him leave, and after a few minutes of the three of them staring at each other, Bruce and Tony went back to their work trying to come up with a way to possibly negate the effects of the serum for when they finally got ahold of it. Natasha watched them for a moment, then turned and went to the elevator to find a place to think, so absorbed in her own thoughts that she didn't notice the look Bruce had on his face as he watched her leave.

He stood frozen for a few moments, absentmindedly twirling a pen in his hand as he chewed his lip. He glanced over at Tony, who seemed to be intensely focused on the work in front of him. Bruce let out a soft sigh, turning to his own desk and rifling through some of his notes, his mind everywhere but on the semi-organized jumble of paper in front of him.

"You know you can follow her, Bruce." Tony threw over his shoulder unexpectedly, startling his lab partner so much that he almost dropped the folder in his hands. "I know you want to."

Tony turned around, watching Bruce stuff his notes into a different folder, smiling sheepishly.

"No...no… she probably wants some time alone. To think. And," he gestured towards the screens around them. "we have work to do."

Tony raised an eyebrow, crossing his arms over his chest. He knew his best friend, saw all the little tells that let him know that Dr. Bruce Banner would be of no use to him if he didn't make sure Agent Natasha Romanoff was alright. He was just so easy to read. Even if they hadn't spent years working together as part of the Avengers, anyone could've seen the nervous hand wringing, the distant longing in his eyes, the nervous lip chewing… it was obvious where he wanted to be right now, and who he wanted to be with… and it for sure wasn't in the lab with Tony.

"Romanoff will have my hide if we screw up this antiserum because you were too distracted to think straight." he said, rolling his eyes. "JARVIS and I can handle running the tests, you've got a distraught lady friend to console."

He held up a hand as Bruce tried to negate what he was saying.

"I'm egotistical, not stupid. I don't know what's going on between you and Romanoff, and frankly I don't really care. As long as I don't have to worry about finding you two tangled up in a broom closet during a mission…"

Bruce's cheeks turned a fiery crimson as Tony grinned, and he laughed uneasily as he ran a hand through his hair.

"Ah… yeah, it… it's nothing like that. She likes to flirt." he shrugged, shoving his hands into his pockets. "She's just helping me with the Other Guy. You know, with the Lullaby..."

"Romanoff is gonna need a lullaby if you aren't able to help me with this antiserum." Tony smirked, a chuckle in his voice.

He watched Bruce gently tap the metal desk behind him with his knuckles as he walked near it, before seemingly coming to a decision and turning to tap the save icon on the screen hovering over the desk.

"Alright, fine." he took a deep breath, clearing his throat as he turned back to face Tony. "I will go check on Nat… and Steve."

Tony shrugged, the smirk on his face growing as he turned back to his own work and waved over his shoulder.

"Don't be out too late." he grinned. "Have her home before midnight."

"Yeah, whatever, Tony." Bruce chuckled, grabbing his keycard and turning to exit the lab. "Won't have to worry about that."

"JARVIS, what're we gonna do with those two?" Tony sighed, shaking his head when he heard the door slide closed behind Bruce.

"I'm not sure I understand, sir." JARVIS replied. "Are we referring to Agent Romanoff and Dr. Banner becoming more well acquainted?"

"Somehow putting it that way makes it so much worse." he muttered, cracking his knuckles decisively. "Anyway, enough of the 'trashy reality show' talk. We've got twice as many simulations to run to make up for the lack of Banner."

He brought up a long list of simulations and formulations, letting out a slight grunt.

"Sorry, Pepper, looks like I won't be getting a whole lot of sleep." He smiled to himself, his voice softening at the mentioning of her name.

"Would you like me to phone Ms. Potts, sir?"

"No, that's alright, J." He shook himself, rolling his shoulders and cracking his knuckles before tapping a pair of codes on the list. "Let's go ahead and run these two."

"Yes, sir."

XXXXXX

Natasha heard him before she saw him. The slight shuffle in his walk was so… so Bruce… that she wouldn't ever think it was anyone else. She smiled. He could be confident when he wanted to, and when he was it was a bit harder to distinguish his walk from someone like Tony or even Thor at times. But tonight, he was the usual Bruce Banner that she had grown to like so much.

"You gonna join me or just stand there?"

She heard Bruce chuckle uneasily, and felt him close the distance a little bit as he came to stand near where she sat on the edge of the balcony near the now-infamous Avengers Tower "A", her legs dangling over the dangerous drop.

"What, you afraid of heights?" she asked, glancing up at him, noticing the way he peered over the edge.

"I'm not exactly a fan of them…" he shrugged, before unexpectedly taking a seat beside her, putting almost a foot of space between them. "But I wouldn't say I'm afraid."

Natasha regarded him for a minute, then leaned her head back towards the dark sky and closed her eyes. Bruce watched her out of the corner of his eye, chewing his lip as he tried to think of something to say to her. He couldn't bring himself to ask about how she was doing, so he settled for the next best thing.

"Do you think Cap'll be alright?" he said, finally turning to look at her directly only to find her still facing the sky, staring at the stars. The light glowing from the street below seemed to be caught in the red strands of her hair, and he forced himself to look away as he felt the urge to run his fingers through them.

"Steve's strong," she said quietly, a sigh escaping her lips. "He's been through a lot and hasn't let it get him down so far, so you know, what's one more mission to save the world?"

Bruce heard the smile in her voice and couldn't help but smile as well, stretching his arms above his head.

"I'm sure he'll feel a lot better if we stop this whole thing in its tracks… you know, before it's actually a matter of saving the world."

"Speaking of which," she moved her head forward to a more comfortable position, raising an eyebrow at him. "Aren't you and Tony supposed to be working on an antiserum right now?"

Bruce shrugged, averting his gaze from hers and instead fixating it on what looked like a helicopter landing halfway across town.

"Tony has JARVIS running some tests. He doesn't necessarily need me for that." he rubbed the back of his neck, a dull blush blossoming on his cheeks. "I figured my time would be better spent um… checking on you. And Steve."

"Aren't you just the gentleman of the year?" Her teasing tone didn't match the gentle smile she gave him, a chuckle escaping when he hastily added that last part about Steve.

"Maybe. Although I think Steve has me beat in that competition." He laughed uneasily, shrugging as he continued to stare out at the scene in front of them.

He really was too adorable.

She felt herself tense as the realization sunk in that she saw him as adorable. Natasha Romanoff never thought anyone (other than Clint's secret kids) was adorable. It also bothered her to realize that Bruce's presence alone had caused this calming wave to wash over her, gently nudging the dark questions about the future to the back of her mind where they couldn't hurt her.

In the few minutes before Bruce had shown up, she had been sitting there, staring down at the cars and lights and listening to the various honks from a traffic jam… and had found herself dwelling on the idea that if they couldn't stop this new HYDRA, even the chaos of the city she called home would seem peaceful compared to what was coming.

But now that he was here, she could only see hundreds of people going about their night without a care in the world, and she found herself smiling at the fact that she had something to do with that.

"It's beautiful, isn't it?" she heard her voice before even realizing it was her who was speaking. "Hard to believe this city's seen as much destruction and insanity as it has."

Bruce shifted at her side, pulling a pen out of his pocket and playing with it gently as he watched a family of four wander into an all-night pizza parlor.

"Yeah, New York has a way of moving on in spite of things…"

They were silent for a while, before Natasha let out a long sigh and ran a hand through her fiery hair before turning to face him again.

"Can I ask you something, Bruce? Something really personal?"

Bruce blinked, his heart beginning to pound in his chest as he swallowed thickly and turned his head to face her as well.

"Uh… yeah, sure."

Natasha bit her lip, knowing that the upcoming question would either infuriate him, make him unbearably uncomfortable… or quite possibly open the metaphorical door to his core that he purposely kept locked for his own safety. But she just had to know. Maybe the timing was strange but… with the new threat they were facing, who knew when they would have another moment alone like this? And this was something she had been wondering about ever since meeting him in Calcutta all those years ago.

"What's it like?" she asked softly, scooting away from the edge and crossing her legs before scooting as close to him as she could without touching him. "...what does a Code Green feel like?"

Bruce tensed, his most basic instincts telling him to run away from this conversation as fast as he could… to get away from the rush of pain and conflict that just thinking about his alter ego brought on…

"Bruce?" she asked quietly, watching his frame tense significantly.

Bruce forced himself to relax, realizing that it wasn't just anybody asking him about this. This was Natasha. He knew her. He knew her motives...she just wanted to help. They were teammates, friends. He liked her. He liked her a lot. And so did the Other Guy.

Maybe that was why he suddenly found himself pouring every detail out to her, unable to stop the flood of emotion as he vividly described the experience from beginning to end.

"It feels like my own personal Hell."

He told her about suddenly feeling sick to his stomach as he fought the Hulk, his mind flooded with pain as his conscious mind was forcefully thrown into a dark hole. He described the ripping and tearing of muscles he felt as they were stretched to outlandish proportions, the ache that resounded through him making him feel a strange sort of weakness even after he finished transforming. He described the feeling of complete and utter helplessness, the feeling of wanting to shut his eyes and block out the terrified screams of those who saw him… but being unable to do more than scream, knowing he wouldn't be heard. He told her about struggling to find something to trigger a fond memory, something that would force him to change back so he wouldn't hurt anyone else, and told her of how frustrating it was when nothing would work and he would simply be screaming in pain into the void.

"I guess it would hurt less if I just willingly let the Other Guy take over and do what he wanted… But then, I wonder would he ever let me come back?" he chuckled almost mournfully. "And then sometimes I wonder… why do I want to come back? What am I trying to regain? Why… Why not stay the Hulk and just let him do whatever he wants? Eventually the world would forget about Bruce Banner… my name wouldn't be tied to the damage anymore."

His voice sounded hollow, something that didn't sit right with Natasha. She felt her chest ache as he spoke, and her voice caught in her throat as she struggled to think of something to say to remind him of just how valuable his life was. How much he mattered to not only the world, but to his friends.

To Tony, who counted on him as a 'science bro' and best friend, keeping his 'head in the game' when he needed it.

To Thor, who had asked Bruce many times about the science behind his hammer and other Asgardian tech, to try and better understand it.

To Clint, who apparently trusted him to keep an eye on Natasha in a battle even though she could very easily take care of herself.

To Steve, who relied on Bruce's intelligence and ability to not act like an egotistical jerkwad to keep the team up to date on various chemical threats, such as the one they were facing now, and what they were comprised of.

To her… who counted on him to watch her back, be there to listen to her both while Clint was away and when he wasn't, to be the one who understood her better than anyone… He was the only member of the Avengers who truly understood what it meant to feel as if they weren't in control for years, to feel as if they had been manipulated and shaped by someone other than themselves, unable to do more than grunt and comply...

"Bruce Banner feels everything the Hulk does." he stated suddenly and quietly, interrupting her thoughts. His eyes were locked on the ground far below them. "The bullets and shells don't kill us… But they hurt. And I feel that pain, deep down in the darkest depths of my mind… I feel it. And... before you, and the Lullaby…"

Natasha watched his face, momentarily startled when his eyes suddenly met hers. She saw his hand twitch out of the corner of her eye as he stared at her, and waited silently for whatever he was about to do. It felt like hours had passed before either of them moved, and she couldn't say she wasn't just a bit disappointed when he simply pressed his palms against the concrete they sat on and averted his gaze again.

"Before… Before the Lullaby, I had no escape." he swallowed. "I just screamed and screamed, pleading and begging to whatever entity that would listen… begging to go back to being myself. Because I know this was all my fault. I'm the reason I'm a monster."

Natasha opened her mouth to dispute that, but he sighed and put up a hand to stop her.

"It is my fault. The Hulk… I created him. It was an accident... but I did." he ran a hand through his hair, struggling to keep his thoughts straight. He looked at her, noticing the confusion behind her eyes. "They… they never told you how I… how the Hulk…?"

"I read...some of your file before coming for you in Calcutta, but...much of it was redacted." she shrugged gently. "I figured it was Fury's doing."

"Only because I requested him to do it. It was the only way I would agree to help with the Tessaract." he shrugged, tossing the pen back and forth in his hands before glancing at her. "I didn't want everyone knowing what I did… what I was trying to do. They might feel betrayed if they all knew. Especially Steve."

Natasha stared at him, leaning in closer, tempted to touch his arm but deciding against it. She hated being out of the loop, especially when it came to something she thought she should know. They were part of a team, she should know everything about each one of them… it really frustrated her to realize that maybe she wasn't as enlightened as she thought she was.

"Steve?" she blinked, her mind reeling. "What about Steve were you…?"

Bruce's eyes darkened, his gaze dropping to the ground below. When he spoke, his voice was slightly deeper, laced with the pain of a man who had lost everything, including himself.

"I was trying to recreate Cap's serum, too." he choked out, a dark chuckle escaping. "But I guess I got what I deserved. The gamma radiation I was using to try and create the serum… backfired on me. And I became the Hulk."

Natasha felt her stomach lurch, listening to the sadness and pain in his voice. She knew transforming into the Hulk couldn't have been a fun experience, the tortured screams Bruce often made while it was happening had made that very clear. But she could've never imagined the helplessness, especially now that she knew that every transformation was accompanied by the crushing guilt he had just talked about…

This man was enduring a pain that no one should have to experience. It was a constant battle, a silent reminder that he had made a mistake that was ruining his value of life. To him, there was no bright side, no silver lining… and no escape. She realized it now, why he was always found helping others whenever he dropped off the map for years at a time. He was attempting to spend the rest of his life making up for the numerous incidents caused by his alter ego. For every life the Hulk took, Banner would save two.

He was trying to wipe the red out of his ledger, as well.

"You know," she started softly, unsure of where she was going but trudging on anyway. "Whenever I've seen you change… I've never been really scared...of him...or of you."

She chewed her lip for a moment, trying to organize her thoughts, watching him glance at her, his eyes laced with some emotion that she couldn't really decipher. He looked.. relieved? Confused? Hurt? Excited? It seemed to be all of them at once.

"Like I haven't heard that one before." Bruce said softly, his heart aching. As badly as he wished he could believe that someone was not afraid of his alter ego, it was just too difficult to come to terms with the idea of someone being that brave...or crazy.

"Years of having fear beaten out of you has its perks, you know?" she smiled ruefully.

As he stared at her, he had to remind himself, again, that this was Natasha. Natasha who had been raised by maniacs to be a killing machine. Natasha, who had left that life behind to try and change her reputation. Natasha, who had been forced to flee for her life from a man she'd been tasked with recruiting in the first place, and was currently sitting beside that same man. Natasha, who had almost been killed by the Hulk and still stuck around to help reign him in. Natasha… who had stuck by his side as they practiced the Lullaby, listened to him talk out his frustrations when the Lullaby didn't work as planned, stayed up with him on the nights where the nightmares from the New York battle were too much to handle… He remembered many nights where they'd sit on the roof, cradling cups of hot cocoa and venting to each other.

"I've thought about running away, again. Dropping off the map. Just to get away from it all. The lull in avenging is...good... but…"

"You'd better not. Not unless you plan on dragging me with you. You're not leaving me here with Stark's annoying whining and Steve's hoards of fangirls."

"Hoards? I mean, I know the guy is good looking but…"

"Hoards. Stark had to write new security coding for JARVIS just to keep them out."

"Um… wow."

"Exactly. So if you plan on ditching the Tower, I'm coming with."

"May not be the smartest idea you've had, Natasha. I can be lousy company."

"I wouldn't know."

But even so, he had still hurt her. He had put her in harm's way, and even though it had been unintentional and a result of Loki's manipulation… and even though she told him many times that she never held what the Hulk did against him...the guilt always returned in full force whenever he tried to believe what she said.

But the way she was looking at him…

"You know what helps me not be scared of the Hulk? His eyes. Your eyes." she corrected. "I saw you in them on the Helicarrier. I saw what was happening to you. To Bruce Banner."

Bruce simply stared at her, his eyes wide. He remembered flashes of her frightened face as he transformed. Remembered yelling at her as she swore on her life to get him out of the situation. He remembered looking at her helplessly as the Hulk finally won, watching her lips desperately form his name before he tore away and was lost to the void in his mind. She was the first person he thought of when he woke up butt-naked in the rubble of the building he'd crash-landed into. He wondered if the Other Guy had killed her.

"I see it every time now, Bruce. I don't see a monster behind those startlingly haunted eyes…" she smiled softly. "I see you. And... because I see you in there… I'm not scared."

Bruce's head felt light as he allowed her words to sink in. He wanted to take solace in what she said, he wanted to so badly...but he couldn't. Not yet. Not without telling her the truth.

She deserved the truth.

"Maybe it's because you don't realize that Bruce Banner is a monster all by himself." he muttered, looking away.

"Bruce…" Natasha sighed. "You can't-"

"There was something I didn't tell you, or Tony, or Steve... that I discovered in the lab." he interrupted, his voice cracking at the end. He cleared his throat, nervously rubbing his wrist.

"Bruce?"

Bruce felt his heart pounding in his chest, his hands beginning to tremble as he gripped his wrist tightly. Somehow the worried tone in her voice made him feel even worse. Everything in his body was screaming for him to throw himself over the edge and hope the Other Guy wouldn't save them this time. He had to get away from all of this… but he couldn't. Natasha had reached out and placed a comforting hand against his arm, and it felt too warm against his skin; the sound of her expectant breathing too calming to him. He took a long, shaky deep breath, forcing himself to simply tell her the truth and hope she didn't throw him over the edge herself.

"The essential unfinished chemical base that HYDRA is building their serum off of? It… It's mine." he swallowed, his voice raising slightly. He hurried through his words, not giving her a chance to respond. "I knew I should have destroyed my research, and I don't know how they got it, but…"

He sighed, deciding not to finish that thought. He turned to her, his eyes wide and his tone tense.

"That's why we have to stop HYDRA before they even start testing, or we won't have to worry about an army of Captain Americas."

The realization hit Natasha like a ton of bricks, and she felt as if the air around them had suddenly gotten thinner as she tried to come to terms with what he was saying.

"It'll be an army of Hulks." Tony said suddenly from the doorway behind them.

Natasha moved her hand from Bruce's arm abruptly, sighing softly when she realized it was just Tony. Bruce turned around, looking startled as well. Tony smirked, pulling out his tablet and walking towards them.

"Sorry to interrupt, again. I know you were having a moment." he smirked.

"What do you want, Tony?" Natasha asked, annoyed.

"JARVIS told me you guys were out here. Thought I'd join you. Anyway, I found Banner's dirty little secret." he shrugged, not noticing Banner's tense reaction as he pulled up the structure of Bruce's serum and waved over it so a holographic projection of it came up. "It's actually pretty impressive. The serum that created the big guy. Impressive. in a… terrifying sort of way."

He joined them at the edge of the balcony, passing the tablet to Natasha next to him as he dangled his legs over the edge. She took it, her eyebrow raised as Bruce leaned over slightly toward her to look at the holographic display.

"It's missing a second base chemical. Something to bind it all together so it doesn't explode like your original one did." Tony stated, pointing towards an empty spot in the serum's coding.

"Yeah, well, I didn't exactly have state-of-the-art tech the first time." Bruce said irritably.

Tony ignored his irritated tone, swiping his hand to the right to open a large map.

"Now, since we've already figured out what it's missing, I'm assuming HYDRA is gonna figure it out too pretty soon. Best course of action? Get rid of the source. I had JARVIS scanning for traces of every chemical that makes up the serum, including the one they don't know about, and so far we've got five distinct hits."

"So we wipe out the sources while triangulating where they are all being shipped to… and we can get rid of the serum?" Bruce asked, his eyes searching the map. "or at the very least make it much harder for them to make enough for an army."

"Making the chance of an all out war much lower." Natasha nodded in understanding.

"Yep, then all it takes is interrogating some baddies to find out who's got the nearly completed serum and how they got Banner's research, so we can wipe it out and be done with this. The only issue is…" he let out a short sigh before tapping a button on his wristband and spreading both of his hands in the air to zoom out on the map above their heads.

"Each location is almost a million miles away from each other." Natasha grunted, sighing as well.

"I...I guess we have some traveling to do." Bruce said after a few moments of irritable silence. "I'll...go tell Steve."

Tony and Natasha watched him get to his feet and hesitate as he stared over the city below. Natasha's muscles tensed, prepared to grab his wrist in case he tried to make an awful decision right then and there.

But he simply looked at her, turned, and walked back into the Tower. They watched the door for a moment longer, before Tony sighed and spoke.

"You're good for him, you know. He actually talks to you." he shrugged. "Trusts you."

Natasha raised an eyebrow at him, handing him back the tablet.

"Has a funny way of showing it." she chuckled uneasily. "but he trusts you too, Stark."

"That may be, but you know how I am. Not good with feelings. You've seen me with Pepper." he laughed, switching the tablet off. "Long story short, we don't talk like you two do."

"How exactly do we talk that's any different than how you two talk?" Natasha asked, a bit confused but also very aware of what he meant.

Tony shrugged, getting to his feet and tucking the tablet under his arm.

"We talk about science, the fate of the world, politics… " he smirked. "You two talk about feelings, your pasts…"

He grinned at Natasha's slightly taken aback expression, her arms crossing over her chest once she stood up and faced him. He chuckled, waving a hand vaguely at the Tower.

"I've got cameras everywhere, Romanoff. Even at your little hideaway up on the roof."

Natasha thought about replying with a snarky remark, but realized she wasn't in the mood to get in a 'battle of wits' with Tony Stark right now. So she settled for rolling her eyes and walking past him, headed back inside the Tower.

"Goodnight, Stark."

"Night, Romanoff. Try not to get lost on your way to bed." he laughed. "Remember that Banner's room is right next to mine, in case you decide to bunk in there."

"Shut up, Tony."

XXXXXX

"Captain Rogers, Dr. Banner is at the door."

"Let him in, JARVIS."

Steve sat in his room on the bed, a standard guest bedroom that Tony set aside for him. The walls were painted the exact same as every other room, the only distinguishing feature being a few small Captain America and US Army posters that Steve had taped to the wall. He sighed as he stared at them, gently polishing his shield. Something that Tony had said before the Battle of New York kept repeating over and over in his head, no matter how much he didn't want it to.

"You're a lab experiment, Rogers. Everything special about you came out of a bottle."

It bothered Steve to realize just how true that was...especially now.

Bruce stepped in hesitantly, smiling a little when Steve looked at him.

"Hey, Dr. Banner." he smiled weakly, returning his eyes to his shield in his lap. "Can I help you with something?"

"Hey, Cap… um, no… I was just wondering... how are you doing? With… with all of this?" Bruce asked uneasily, flashbacks from when Tony thought he was a psychiatrist flashing through his mind as he leaned against the doorframe.

Steve chuckled, setting his shield down gingerly on the floor next to his foot.

"I'm not sure. All I know is I'll feel a whole lot better once it's all over. Did Stark find anything useful?"

Banner chewed his lip, wondering if he should tell Steve that the serum was his creation...that it was what caused the Hulk… or if he should just wait. He decided on the latter, realizing that Steve had enough to think about as it was. The rest could wait until tomorrow after everyone got some sleep. At least then he would have some backup if Steve decided to try and decapitate him with his shield when he found out.

"Y-Yeah we… we have to sort of take some plane trips to track down the serum. Tony and Natasha… I mean, Agent Romanoff... they're gonna give us the rundown tomorrow."

Steve smirked at the pink tinge on the Doctor's cheeks. He was old, not an idiot. Anyone could have seen the secret glances, heard the whispered comments, felt the tension… and known that Dr. Banner and Natasha Romanoff had a thing for each other. Even if both of them denied it vehemently. He didn't even know why they tried to hide it at this point.

"Sounds like a plan."

Steve watched Bruce's gaze unfocus for a brief moment, and he sighed. He could read the apprehensiveness all over his face, could see the fear and worry in his eyes. What he didn't know, was that the worry was not about what he thought it was about.

"We'll find the serum, Doctor." he said reassuringly. "This won't get out of hand. We won't let it."

Bruce smiled weakly, standing up straight and nodding slowly. Steve noted that he didn't seem assured, only slightly less terrified.

"Yeah… yeah, I know." he shrugged. "Anyway… 'Night, Cap."

"Goodnight, Dr. Banner." Steve chuckled, watching him leave the doorway and head to his own room.

XXXXXX

As he silently walked to his own bedroom, Bruce was so caught up in his own thoughts that he didn't even hear Natasha's footsteps coming around the corner. It was only when he almost knocked her to the ground that he realized what had happened. His arm went instinctively around her waist as they collided, pulling her tightly against him before she even got close to the ground. Her hands went to his shirt, fisting it tightly in an attempt to keep from falling as well. They were both still on their feet, their faces only inches apart. His breath came out in soft pants, his eyes frantically searching hers, the adrenaline that had flooded his brain making it hard for him to keep up.

"S-Sorry, Natasha… Are you okay?" he blushed heavily. "I wasn't paying attention."

Natasha stared back, her face feeling hot, a strange wave of both embarrassment and excitement flowing through her, sprouting from where his arm was. It took her a moment to speak, the sudden fog in her mind created from staring into those warm brown eyes of his slowly dissipating.

"Y-Yeah, I'm good." she finally managed, her mouth feeling dry. "Thanks for catching me."

A moment passed, their breaths mixing in the small space between them. Natasha searched his eyes, suddenly wishing they were under different circumstances where they could simply stay this way for as long as they wanted. There was something protective and confident in the way he held her, and she was shocked to find she liked it.

Eventually, Banner was able to regain his composure and let her go, rubbing the back of his neck. She let go of him as well, and he took note of the slight reluctance in her movements.

"Ah, sorry. Again." he smiled sheepishly. "You sure you're okay?"

Natasha couldn't help but smile, running a hand through her hair before nodding.

"I'm fine, Bruce."

The tenderness in her tone startled both of them, but they managed to keep their shock hidden behind awkward smiles.

"Ah… Good. Well, goodnight Natasha." he smiled shyly, shoving his hands into his pockets.

"Goodnight, Bruce." she smiled back, walking past him towards her bedroom.

Bruce watched her go for a moment, before shaking himself and hurrying to his own room for the night.

A/N: Next chapter: our heroes begin a long journey around the world, tracking down the components of the serum to find the source of the problem! This story is growing wildly out of control and honestly I am loving it! I wanted to get some interaction between Tony and Nat, and also Bruce and Steve. I hope I did okay lol Oh! And Nat and Bruce's convo was really the only part inspired by the song, and really by 'inspired by' I mean I wrote the chapter while listening to the song on repeat lol thanks for the reviews! You're the best! 3