Warning: There will be a little swearing outburst...

"(Y/N)!"

"(Y/N), come on!"

"(Y/N)- oh, seriously! Does anyone know where she is?" Steve huffed, completely frustrated with your tardiness for the third mission in a row. As you finally entered the hangar, your gear hanging loosely from your pack and your hair a complete mess, he stood with his hands on his hips at the jet door, blocking your entry.

"Excuse?"

"I don't have...one, sir," you panted, trying to catch your breath from running the stairs. "I just...lost track...of time."

Clint poked his head out from the jet, smirking at you from over Steve's shoulder, "Nose in a book again, you nerd?" When you didn't respond with the embarrassment or laugh that he was hoping for, he sulked away back to the pilot seat in defeat.

"Let's just go, (Y/N)," Steve relented, "one more time, and we need to have a talk."

"Sir," you agreed, your head down and watching your feet as you quickly ducked past him and into a seat. Keeping your eyes averted as he passed by, you grabbed your tablet from your bag and returned to your work that had made you so late for this mission. It's not like they really needed you anyway; you weren't a fighter, you were there for tactical support and intelligence acquisition. You had been studying with Bruce for a year before Ultron, and now that he hadn't returned yet, you had taken his place working with Tony. The unlimited access to the lab and everything in it gave you enough side projects to last a lifetime.

"You know what, I've changed my mind," Steve announced, dropping himself into the chair next to you, "let's have a talk now."

You quickly returned your tablet to your bag and turned to face him, giving him your full attention and a small smile, trying to stay on his good side, if you were even there now. "Sure, Captain. I'm all yours."

The immediate flush of red in your cheeks had to be painfully obvious; you'd had a crush on Steve since your first day, and you did a good job of avoiding him as much as possible when you didn't have to work together. Your whole body became hot from your overwhelming embarrassment and shyness. "I mean...I meant...I'm all ears. All. Ears."

"So tell me, (Y/N), what are you working on that has you so enthralled that you forget when our departure times are? We knew about this four days ago."

"It's nothing," you replied coyly, hoping that he wouldn't dig any further and just wanting this moment to be over.

He eyed you suspiciously, deciding what he would say next. Rather than pry and ask more questions that would likely have more vague answers, he reached down into your pack and removed your tablet, standing quickly and taking it to the front of the jet.

"Cap, don't!" you called after him, throwing off your harness and chasing after him. "Steve, give that back!" You leaned over the back of his chair, pushing yourself forward to reach so that your feet were now dangling off the ground, but still unable to get a hold of your work. "Steve, come on!" You were starting to panic when he wouldn't release it, but now you were terrified when you saw his expression change and his posture straighten as he read.

"(Y/N)," he said quietly but sternly, "what's this?"

"It's just a project. It's nothing."

"I don't believe this," he sighed, turning to face you. "Have you succeeded? Have you really replicated the serum?" Clint now turned to look at you as well, his mouth agape. "(Y/N), answer me."

You slid back and dropped onto your feet, rubbing your hand over your face in frustration of your exposed secret and the need to explain something that they likely wouldn't understand. "Well clearly not," you hissed, raising your arms up to show their lack of accentuated muscles. "Do you see any difference?" Ripping the tablet from his hands, you returned to your seat and continued to work.

"You can't experiment on yourself. That never turns out well, (Y/N)."

"What I do on my own time is my own business, Captain. Excuse me." You lifted the tablet to definitively show that you were finished with the conversation, and Steve chose not to push. He took his seat in the co-pilot position, looking out the window as Clint manned the controls.

"So that's why she's never around?" Clint asked. "She's locked up in the lab all the time?"

An answer never came, as Steve continued to watch the sky until you came to a landing almost two hours later.

~~~

"Okay, (Y/N) and Natasha, you two can move in and collect the data and fry their systems while Clint and I secure the hostages." Steve's eyes widened as you took a gun from Nat, securing it to your thigh. "(Y/N), since when do you carry a weapon?"

"Since now, I guess? I just have a feeling like I should have one this time." You gave him a small shrug as you jogged away, not really caring why it made a difference to him. "How hard can it be, right?"

"She's totally gonna shoot herself in the foot," Clint scoffed, slinging his bow over his shoulder, "I don't think she's ever even held a gun."

All Steve could do was shake his head as he led them into the building, holding a finger to his lips to keep Clint quiet. "Are you in position?" he whispered into his comm, "be ready to move." As he reached the bottom of a long stairway, he saw his targets, keeping watch around a small group of hostages, bound and sitting on the floor. "Barton, go help the other two, I can manage this."

Clint nodded and left him there, waiting for the correct moment to strike. Once Steve had his plan of attack ready, he signaled you to go, quickly taking out three of his five opponents with ease, but losing the other two when they ran outside. "Barton, two on the run!"

"I'm on it!"

"Cap, Nat and I are headed your way, we're done here," you called to him, but there was no reply. "Cap? Steve?" You looked to Natasha and broke into a sprint to get to his side of the building, hoping that you weren't going to find the worst outcome playing out.

He would have called for help, right? Maybe it was just a technical glitch. Maybe he was ambushed. Maybe you should stop thinking and just get there.

You took the stairs three at a time, practically throwing yourself down them to get there faster. When you reached the bottom, you stopped in your tracks, gasping at the sight of Steve on his knees with a gun to his head.

"Hey guys," he said calmly. "I'm in a bit of a situation..."

Without a second of thought, you pulled your gun from its holster and held it steady, ready to shoot the man who was directly behind Steve at the first chance of a clean shot. "Step away from the Captain, please."

"(Y/N)..."

"Shut up, Steve," you said in a cool and even tone. "I said, step away."

"I don't think that you're in any position to make demands," the man said, pushing his gun forward more. "You're taking a gamble with your Captain's life."

"Drop your gun before I blow your fucking head off."

Steve couldn't hold his composure anymore; his eyes widened and his mouth hung open, looking at Nat who mirrored his expression. This was certainly a shift from the you that they were used to; the one who spent all day in the lab and kept pretty much to yourself unless on a mission. He wasn't sure if he should be impressed or frightened.

"I'll give you five seconds-" the man began, but you wouldn't allow him to finish.

"Do you wanna go?" you challenged, "do you wanna go, you worthless little prick? You have the balls to go up against Captain America and think you have a shot at winning? How fucking stupid are you?"

The man's mouth hung open, clearly not expecting this type of resistance; he changed his plan, now raising his weapon at you. "I don't think you understand-"

"Alright, I'm done," you snapped, pulling the trigger to land a shot square between his eyes. "If you're not going to listen, then that's what you get."

"Okay, I'm thoroughly terrified," Nat chuckled. "(Y/N), that was...new, to say the least."

Steve was still on his knees and still staring; looking at you as if it were the first time seeing you. "What the hell just happened?" he whispered.

"I saved your ass. Your welcome."

"Thanks..." he replied, still uncertain of his voice. "Um, yeah...so, we should probably go."

Once the transport picked up the hostages and you were on the way back to the jet, not much was said; Steve looked lost in his own mind, Natasha was still impressed, and Clint was just confused because as luck would have it, he missed the whole thing. As soon as you were secured in your seat and in the air, you grabbed your tablet and returned to your research as if nothing had happened.

"Can I join you?"

"Yeah, Captain, go ahead."

He leaned forward in the seat, his arms resting on his legs as he started to wring his hands together. You watched him in your peripheral vision, waiting for him to begin the conversation, but when the wait grew too long, you took the initiative. "Just ask. I know what you're going to say."

"(Y/N), I've known you for a long time now, and I've never seen that from you. Don't get me wrong, it was remarkable, but I don't understand where it came from. I think you do."

You took a deep breath and dragged your finger across the tablet several times until you came to the information that Steve had seen earlier. "You know that the serum is maximized by the use of Vita-Rays, but when used alone there are greater potentials for side-effects. I don't have Vita-Rays at my disposal." You handed the tablet to him, as you continued, "it would seem that I might not have gained the strength, but my nervous system is at peak performance, meaning my senses, memory and muscle control are exceptional."

"That's why you had perfect aim despite never having shot a gun before," he said under his breath with a nod of understanding. "Okay, but even your personality was different. Is that a side-effect too?"

"No, I was just feeling bitchy," you laughed, "and I knew I had him so maybe I was a bit cocky too."

Steve leaned over and nudged you with his shoulder, giving you a wink, "don't tell anyone, but I kinda liked it. But seriously, thanks."

"You're welcome. If Bruce is right, these side-effects are likely permanent so I might..." Your voice trailed away at the realization of what you had just said, squeezing your eyes shut and hoping that he didn't catch on.

"What did you just say?"

"Side-effects are permanent?"

"Do you know where he is, (Y/N)?" he said in a solemn tone, almost sad that he had to ask.

"Yes. He's safe and hidden and not coming back," you said firmly. "Now leave it, please."

Steve nodded his head and turned to you, taking your hand in his. You could feel the shake building inside of you and you worried that he would notice. "I'll leave it. But you need to do something for me. You need to leave this." He took the tablet and threw it in your pack, looking at you with determination to keep it there. "Do we have a deal? No more experiments. No more research."

"I owe it to Bruce to say yes, we have a deal."

"Great," he said with renewed enthusiasm, standing to return to his seat. "Tomorrow we can start planning your training with Nat. I think it's time to move you out of the lab to be with the three-dimensional people."