A/N: Hey Snowbarries ! Look who's back with a new AU Snowbarry story ?!

Okay, so this is probably a bad idea, because I'm in the middle of my exam period, but this idea couldn't get out of my head. I got it while going through the Percy Jackson fandom (seriously, these guys have the most AU stories/ideas I've ever seen) and I thought that it could very well fit for our favourite Scientists. So here you go, a Spy AU :) Hope you like it and tell me what you think about it ;)

I don't own anything :)

'Keep running you almost got him…'

He turned around the block and immediately spotted his target taking the next turn. The streets were now busy so he had to jump between people, trying to avoid hurting anyone in the process, to keep up with his target. He put is gun back in its place, its barrel under his jeans against his back, his shirt and jacket covering it and he tried to run faster. It was in time like these that Barry wished he had some kind of superpower – like super speed, that would be nice. Because right now his legs were beginning to tire, his lungs were burning, his heart was beating harder and harder, his feet were making more noise at each stride and he didn't seem to get any closer to his target.

'Suck it up and deal with it' he thought to himself. Gathering what was left of his energy, Barry launched himself forward. He was trained for this – he could do it. But seriously, he didn't know how it was possible that his target had still so much stamina and that his pace didn't lessen. They had been running for what felt like hours and Barry didn't seem to get any closer. And it was very frustrating because he could feel his energy burning down. But he had a job to do and he couldn't give up.

"Barry!"

He almost missed a step at the shrilling sound in his right ear. Damn, he had forgotten about his earpiece.

"I can't really talk right now." He huffed in response in the lapel of his jacket. "Except if you have a way to help me catch this guy!"

"Stop running." The order didn't leave much room for any debate. But Barry kept running anyway.

"No, I almost got him, I'm not going to give up now." He scolded back. This conversation was distracting him from his goal; he was going to lose some precious time. And his target.

"Barry, stop right now. We've got someone closer to him to take over."

"What?" Barry almost shouted – making people around him glance curiously in his direction. But thanks to the 21st Century and its technologies, they didn't seem to care much about an agitated guy talking alone in the street. "No, this is my case!" Barry groaned more quietly but still very firm in his conviction.

"I know, but Oliver wants you back at the HQ. Now stop running, and get your ass over here. He's got a more important case to hand over to you."

Barry stopped on his tracks when he heard the communication being shut down in his earpiece. He was now in the middle of a busy street, bending over with his hands on his knees, trying to gain back his breath. His target was nowhere to be seen. After a few moments, he looked around him and punched angrily the air with his fist.

All of this had been for nothing.

And now Barry had actually no idea where he was or how to get back to HQ.

"Great." He muttered to himself.

"You blew my whole game out there." Barry complained as soon as he entered the office. He didn't know how many times he had been here. But he wouldn't be surprised if the number was close to the number of days since he had begun working here, even if it wasn't his office. No, it was his handler's office. Well, handler and IT expert. She had taken him under her wing as soon as he had arrived on the job.

The young woman behind the computer threw him an apologetic look above her glasses. "Sorry, but you know I don't decide that kind of stuff."

Barry shrugged and let himself fall on a chair not far from her desk, lifting his feet on the table. "I know Felicity." He let his hand go through his messy hair while stretching a bit. The shower he had taken as soon as he arrived at the HQ had been invigorating. Barry huffed. "Well, could you tell Mr. Queen that I don't like being taken off my cases before I finish them."

Felicity glanced at him and rolled her eyes without even taking the time to reply.

"So… What's this case Oliver wants me to take?" He finally asked.

"He'll tell you all about it himself." Felicity replied without taking her eyes off her computer screen.

The young man groaned. He wasn't sure he would get any serious answer from her today.

"Take your feet off my wife's desk, Allen!" The deep threatening voice came from behind him. Barry almost jumped up from his chair and sat straighter. He turned around to nod at his boss, standing in the doorway of the office.

Barry Allen had known Oliver Queen for a few years now. But he couldn't help being scared of him, even if he knew he was a sweet human being under his armour. Barry could count on the fingers of one hand the number of times he had seen that side of his boss. One of them had been his marriage to Felicity Smoak. Since that day, Barry considered her as Oliver's calming force.

"So, I heard you had a new case for me?" Barry asked.

Oliver pushed himself away from the doorframe against which he had been leaning and threw a consistent file on the desk in front of the young man. It made a loud "thump" as it landed. "Yes, I want you up to date with everything in this file for tomorrow morning, 8 O'clock."

Barry wide-eyed the big file in front of him. That was going to be a long read, he thought bitterly. Before he could comment on it, Oliver spoke again. "I'm sending you in a new undercover mission. But it's probably going to be longer then what you're used to. I hope you're up for it."

Barry felt his blood boiling in his veins. His boss was trying to rile him up. Of course he was up for it! Barry was one of the youngest special agents in this private investigation firm. He was also one of the bests. But if Oliver was trying to push his buttons, it was because he needed Barry's total focus, which surely meant that this was a serious case.

A very serious one.

Barry pinched the bridge of his nose as he felt a headache threatening his brain. He lazily rubbed his face and glanced at the clock on his computer.

3 am and he was still at the headquarters, reading his file. He thought his head was about to explode. So many information and he still didn't get what he would have to do. Maybe the team meeting at 8 would clear things up a bit.

What he knew about the case until now, was that some Dr. Wells, owner of the S.T.A.R. laboratories, had had shady behaviours in the past few months and that Starling Investigation – the firm Barry was working for – was fearing some kind of terrorism attack. Or something like that. Anyway, Dr. Wells seemed to be a threat to Central City.

The file contained all sorts of information about every single S.T.A.R. labs' employee, every project they were working on – that they knew about – and every suspicious thing about the whole laboratories. It also contained a whole new life for Barry Allen. His covert identity didn't seem very complex. He would have to pose as a young forensic expert working at CCPD and his back-story didn't really divert from his real one: no parents, love for science, grew up in Central City, graduated at the top of his class…

Fortunately, Barry wouldn't have to actually work as a crime scene investigator – he would just pose as one. Because as much as he loved science and knew a bit about forensics, he didn't think he had the ability to do this work. Thought it would've been on the top of his list of study choices, if he hadn't decided to become a spy.

Barry glanced at the clock again. He should probably go home to get some sleep before the meeting. He leaned back in his chair and the lightning bolt sign, pinned to his wall next to his computer, caught his eyes. His co-workers had given him the small symbol to fit with his nickname: The Flash. He had gained this name because of the speed with which he could close a case and he was pretty proud of it. It was some sort of tradition here, to give someone a nickname. For example, Oliver Queen was called The Arrow, because of his strict and "straight as an arrow" persona.

Barry chuckled alone at his desk and a yawn escaped at the same time. It really was time to get some sleep.

"So Mr. Allen, did you do your homework?" His boss asked as soon as he entered the conference room.

Barry fidgeted on his chair from lack of sleep and too much caffeine. "Yes sir, but I didn't quite get what you're expecting from me." He replied awkwardly. He hated feeling dumb, like he hadn't been smart enough to read between the lines of his file.

"We want you to infiltrate S.T.A.R. labs to investigate and find some solid and valuable intel so that we can stop Dr. Wells before he does something unforgivable." Oliver replied as he sat on his chair at the head of the table.

Barry rubbed the back of his neck with his left hand. "And how do you expect me to do that? If I understood correctly, these laboratories are very good guarded… and I'm not sure there are any forensic job offer there either."

"And they have a strict 'No Visitors' policy." Felicity added, while typing nervously on her laptop next to Oliver.

Barry glared at her. She wasn't helping his case, at all.

"That's why we want you to get close to the employees there." Oliver continued.

Barry seemed to hesitate for a moment. "Sorry, no disrespect, but I'm not sure they do exceptions for friends. The place is a damn fort."

A small smile appeared on his boss's face. "Exactly. So the plan is to become more than friends with one of them and they might do an exception."

"I'm the one who came up with that idea." Felicity commented as she looked up from her laptop excitedly.

Barry choked on the water he was drinking and a fellow special agent, John Diggle, had to tap on his back so that he wouldn't suffocate. "You want me to… you…" Barry stuttered, not finding the right words. "You want me… to… seduce… one of the employees?" He finally managed.

Well that was new. He had flirted with targets before, sure. But he would have to get really close to this person to gain access to the labs.

"Well seducing is a big word." Felicity noted. "More like getting close enough to be considered as their significant other. Win her affection, hang out with her, date her."

"Sounds like seducing to me." Barry grumbled to himself and heard Diggle chuckle next to him. "I imagine you have chosen the lucky one." He continued louder.

Oliver nodded. "One in particular. She's one of Dr. Wells's closest employees. She has access to almost every files and she's one of his favourites advisors. She's also at the head of her own team."

Barry had read the biography of every employee at S.T.A.R. labs and he was trying to remember who fit to the description. He remembered having been impressed by her resume – a brilliant female scientist almost at the head of a huge laboratory. He just couldn't remember her name.

Oliver spared him the trouble of searching further. "Her name is Dr. Caitlin Snow."