A/N: So this chapter is my character's back story, and is set about a year and a half before 'Avengers'. I am doing this so that you know who the character is and how they got in their current situation. When this is over I will get into the main story, I just felt I needed to set the scene :) Oh, and if anything confuses you just ask; I love getting feedback :) P.S I am British, so please excuse any British spellings/meanings for certain words :)

The young girl sat in the high-tech cell, with her arms wrapped around her knees as she cried. She couldn't of been older than sixteen, she had dark brown hair tied in a loose plait to the side of her head, and her face was damp from the tears that had streaked down from her deep brown eyes; that looked almost black in the dimly lit room. She had tanned skin, was about five foot eight and she was of medium build. She risked a glance up at the security camera that was watching her from the corner of the room, before resting her forehead back onto the top of her knees, her navy skinny jeans preventing her from bringing her knees any closer to her head. She flinched as she heard the door click open, and a man in a tailored suit walked into the room.

"Pl-please don't, don't hurt me.." she stammered as the man stood opposite her, his shadow looming over her.

"I'm not going to hurt you, we're not going to hurt you." the man replied, his face looked worn, with lines tugging the corners of his eyes and mouth. His sandy brown hair thinning at the forehead.

"But, why am I here? I didn't do anything wrong, I want to go home!" the girl burst out into sobs again as the man sighed.

"What is your name, miss?" he asked, trying to get through to the near hysterical girl.

"Leila, Leila Shaft." she managed to say, in between her crying.

"Well Miss Shaft, my name is Agent Coulson and you haven't done anything wrong, we just need some information." She looked up at him, surprise evident on her face.

"B-but, what would I know?" she stuttered, as her tears began to subside.

"Someone is going to come and speak to you in a minute, and then we will be able to let you go." Agent Coulson said as he turned to leave.

"But I still don't understand, what would I know that's so important to you?" she sniffed and wiped her eyes with the sleeve of her pale blue hoodie, before lowering her head back down to her knees.

"We'll soon find out, won't we?" he walked out of the cell, and the girl waited until she heard the click of the door before she looked up again.

"I don't know Sir, but I think we have the wrong girl, I mean look at her! She's a complete mess, she won't know anything!" Agent Coulson was frustrated, he had been told that they had the girl that could lead them to what they were tracking but this girl was just some scared teenager! She wasn't even hiding anything, all he could read from her when he entered that cell was pure fear.

"Just wait and see, she may know more than you think. Good luck Agent Coulson, I have some business to attend to." The man on the screen disappeared, and Agent Coulson turned his gaze back to the screen showing their newest 'guest'. But what he saw was not what he was expecting. Where Leila had been sitting was empty. Where is she? He thought. He sounded the alarm, and men went rushing to her cell.

She had to escape. She thought to herself, if she is stuck here any longer things will get ugly. She sat up, and walked over to the camera in the corner of the room. She pressed herself up against the wall directly underneath the camera, which conveniently happened to be close to the door. Now in the camera's blind spot, she waited for the alarms.

She smirked to herself as she heard the beating of the boots heading towards her cell. The door slid open, she held her breath; then she brought her leg up to kick the man in the face; knocking him to the ground, before she twisted the other man's gun from his arms, disarming him, then knocking him to the ground. She slid past the now unconscious men on the floor and out of her cell. She stepped out into an open corridor that stretched on for a few hundred metres. She ran down the corridor past huge vault doors and many other containment areas.

"Nearly there, nearly there.."

She skidded round the corridor to the left and saw many armed guards dressed in black, all-in-one suits coming towards her from the opposite direction.

"Fantastic!" She spun back around to the corridor on the right hoping that this corridor looped around to the exit. As she ran she could hear the sound of boots coming from behind her, but she was silent as her pumps padded lightly on the floor.

Agent Coulson had watched in horror as the teenage girl, a hysterical mess just minutes ago, disarmed two of his agents, before disappearing down the hallway. She was heading for the exit, he couldn't let her get out; she obviously knew something. "All agents on red alert, detainee has escaped; detainee is hostile but does not possess any imminent danger. Restrain and bring back to holding cell." Coulson then watched as Leila(he wandered if that was even her real name) knocked five more men to the ground before she ran straight towards the exit. He then gazed in horror as men open fired on her, in their desperate attempts to stop her.

"What are you doing? She has valuable information stop shooting at her!" He shouted down his earpiece. He saw her stumble but she kept running.

She felt something hot tear at her side; but she couldn't stop to look. She had to keep running. She turned out of the main building, realising that it was pitch black outside. How long was I in there for? She was aware of the many agents that were gaining on her. She came to the edge of the facility and was confronted with a huge fence. She took a few steps back, then ran at it full speed, hooking her feet in the gaps in the wire mesh. She landed gracefully on the other before running in what she hoped was the direction of the nearest road. Perhaps I could get a lift, she thought.

She trampled through shrubbery and shoved her way through a large bush before jumping over a barrier and onto a highway. This was crazy, she was crazy! She shouldn't of got on S.H. I. E. l. D's stupid radar in the first place, now she was a walking target. Not to mention the fact that she was on some road in the middle of nowhere! It was at that moment when she felt the searing pain shooting through her side; she had been shot! Blood was seeping through her hoodie, her hands instantly moved to try stop the blood flow.

"Great, because this situation couldn't get any worse.." she muttered to herself.
She turned her head to the right as headlights blinded her view. She glanced at the car outline and breathed a sigh of relief when she noticed it wasn't a government car. She stumbled to the middle of the road and removed one hand from her side and waved for the car to slow down. She started to feel faint; she was loosing blood fast. She watched as the car slowed to a stop in front of her and two figures rushed out to see if she was okay. As they got closer she could she that one of them was a man and he seemed quite young, but it was too dark to see any of his facial features in detail.
"Are you okay?" he asked, his voiced seemed soft and gentle.
"Please, help me." her eyes glanced at her side, she was going to loose consciousness soon. She watched him follow her gaze and he breathed out heavily, almost sighing.
"She's bleeding a lot, Alex we need to take her to a hospital!" the second figure spoke up, a young girl who was standing cautiously behind the man; whose name appeared to be Alex.
"No, please, don't take me to a hospital, they'll find me." her breath was quickening, she couldn't pass out now; but she could feel the darkness taking over.
"Who will find you?" he asked sounding worried.
"S. H. I. E. L. D." she breathed. "Please, trust me, you can't let them find me." She felt the blackness cover her like a veil as she slipped into a dreamless sleep.

The first thing she was aware of was that she wasn't on the hard road she passed out on, but something soft. A bed? she thought, how did I get in a bed? She was also aware of the smell of something sweet wafting in the air and tickling at her nose. Her eyes flicked open; instantly taking in her surroundings. She was in a square bedroom in someone's apartment. The walls were painted white to match the bed covers; there was a huge floor to ceiling window directly opposite where she sat on the bed, however the curtains where drawn so she couldn't see where exactly she was. There was a wooden chair next to the bed, which was a huge double bed with a wooden frame to match the pine desk that was to the right of the bed. There was also a white, plush couch to the side of the chair.

She sat up properly and spotted a note lying next to her on the pillow. She picked it up and her eyes glanced over the handwritten scrawl.

"There is a bathroom through the door on you left, there are some clean clothes, feel free to clean yourself up."

She knew she should be weary, but she was so tired she didn't care any more. Anyway, if these people wanted to kill her they would of done so already, whoever these people were in the first place.
She twisted her legs over the side of the bed and stood up. She felt a shooting pain ripple up her side and turning to look she remembered the events of the previous night. Well she hoped it was the previous night, she had no idea how long she had been unconscious for. She walked slowly to the bathroom and slide open the door. It was a small but modern bathroom, with a walk in shower to the left and a huge mirror and marble sink to the right. The marble floor making it look like some kind of rocky kaleidoscope. She felt horribly out of place, but surely enough resting by the sink was a small stack of clothes. She looked to see what was there, and there was a dark blue t-shirt, some denim skinny jeans and a black hoodie. There was also a clean white towel hanging on the towel rack. She sighed and glanced at the shower. It did look inviting and she needed to relax before she thought about what she was going to do.
But first she needed to check her wound, it wasn't that painful, but then she had always had a high pain threshold. She lifted up her t-shirt and inspected the wound. The bullet thankfully hadn't hit anything important and had just gone straight through. Will be healed soon enough she thought. She sighed again and headed for the shower.
She turned the heat up high and let the water loosen her muscles. She was an idiot for coming in the first place, she knew that, she just needed to get away. She had no idea that she would be picked up by S. H. I. E. L. D's radar, heck she didn't even realise she could be tracked. She was definitely going to have to do some serious hacking to remove her files when she got back- if she got back, she had no idea where she even was, and yet here she was getting a shower in some strangers apartment. She stood in the shower a little longer, letting the water run over her skin.
Grabbing the towel of the rack she wrapped it around herself and walked over to the small cupboard next to the sink and got out a bandage. She didn't know if it had been put there on purpose but she was going to use it anyway. Wrapping the bandage round her waist she wondered if her wound would take longer to heal than usual, she hoped not, as she could tell she would have to do a lot more running soon. Fiddling with the ends of the bandage she finally managed to tie it. She then got dressed into the borrowed clothes. Surprisingly the clothes fit, the jeans hanging a little loosely and the hoodie almost went to her knees, but she didn't mind; she liked wearing her clothes like that.
She dried her hair with the towel then messily plaited it to the side of her head; the shower had caused her hair to go wavy and unfortunately there was no way for her to straighten it. Frizzy hair it is she thought.
Roughly folding the towel she chucked it back on the rack then walked back into the bedroom. She walked towards the door that led out to the rest of the apartment, her hand resting on the door handle as she hesitated. Open the door you idiot, you brought this on yourself. Right, she was right, this was her fault and her mess, she may as well fix it.

Opening the door she found herself walking into a open plan kitchen, that led into a living room which had a huge white couch, with a glass coffee table in front of it, and behind that was a large flat screen TV attached to the wall. There was also a huge glass table, which looked like it doubled as a board room; as there were touch screens attached to it, and a cabinet that looked like it hooked up to some kind of wireless connection. Sitting at the table on a laptop was a man that looked vaguely familiar, and it took her longer than usual to realise that it was the man who helped her last night. He didn't look much older that her, with chocolate brown hair that was almost in his icy blue eyes, that glanced up as he heard her walk into the room. He was wearing a plain black t-shirt and black skinny jeans. He was skinny, but still looked like he had some muscles, and he looked like he knew how to fight. (She was good at analysing people, it's something that she normally hides, but it can be useful.) She heard a noise come from her right and she turned to look in the kitchen. It was very modern with glass tops to match the rest of the décor in the house. The source of the noise was a girl who looked about twenty, with blonde hair that hung in ringlets at her shoulders. She had blue eyes also, but they weren't at piercing as the boy's, but they showed kindness, which made her relax a little in these foreign conditions. The girl gave her a warm smile and turned her attention back to what she was cooking.

"Hey sleepy head, sure you don't want to go to a hospital? You did get shot." the voice made her jump, and she turned around to see the boy had gotten up and was walking over to her.

"No thanks, I'll be okay." I hope. "Umm, I guess I should thank you, for picking me up, and the bed, and the clothes." She was still weary of these people, which in result made her sound like a rambling idiot. "I mean you and your, umm, friend? You guys saved my life, I owe you. I mean anyone could of found me, and I hate to think what would of happened if it'd been someone else.."
She rambled on again but she was truly grateful, she was a bit careless sometimes and these people picked her up off the road and let her into their apartment. Wait for the catch she thought.

"You have a British accent, interesting. Oh sorry, introductions right, I'm Alex and that's my sister Hannah." he said pointing to the girl, who gave a wave and another smile. He continued talking; "But can I ask what you did to piss S. H. I. E. L. D off? I mean, they're a pretty top secret organisation and the fact that you managed to escape is even more impressive." Great, here's the catch.

"Alex! Sorry, he just wants to make sure you're not some terrorist or something, he doesn't want to be tracked down too." Hannah explained his rather demanding outburst.

"I'm sorry but, how do you even know about S. H. I. E. L. D? Are you the good guys or the bad guys?" she asked. May as well get it over with.
"Don't worry, we're the good guys, we are like consultants for S. H. I. E. L. D, if they ever need our expertise, advice or technology then we can help. We don't exactly agree with the way they do certain things, but it's a better job than being a bad guy." Hannah laughed, but stopped when she saw the warning look from Alex.
Consultants huh? Interesting, she didn't know S. H. I. E. L. D had consultants.

"Well don't worry, I'm a good guy too, it's just a shame other people see it like that." She smiled when she saw their stances relax a bit and she continued, realising she may as well get this over with. "My name is Arianna, Arianna Halverson, but I prefer Anna if you don't mind. S. H. I. E. L. D 'detained' me because they thought I had information about an unusual source they were tracking. I escaped before they could ask me anything, but obviously it didn't go as successfully as I planned." she motioned to her waist.

"But why not just give them the information on the source?" Alex asked, he had walked back to his laptop at the table.

"Isn't it obvious?" Anna asked. "I was the source!"

Hannah and Alex stared at her and the apartment was silent. Then Alex's laptop beeped loudly, making everyone jump.
"According to this, the only 'Arianna Halverson' matching your description died six years ago in a house fire with her parents in London; aged 10." he looked up from the screen and raised an eyebrow at her.

"That's me. I should've died that night, but I didn't, for reasons you wouldn't believe. Plus, being dead helps keep you off the radar. That's one smart computer you've got there by the way, it's normally very difficult to find me." She smiled, they were good, not long until all my secrets are out.

"But that can't be the reason for S. H. I. E. L. D tracking you though, is it? What's the real reason?" Hannah asked.

"You wouldn't believe me if I told you." Anna replied simply, you would hand me right over to S. H. I. E. L. D as well, she thought. Errghh, she thought too much for her own good.

"Try us, you'll be surprised at some of the things we seen or experienced. Plus all the stuff we've read on S. H. I. E. L. D's server." Alex challenged.
Anna took a deep breath, time to face your demons.

"I'm an Angel." She said simply. "Well, when I say Angel, I mean I have wings, and I heal fast; so I can't die. Plus I have slightly more enhanced abilities than normal humans. Oh, and I'm technically an alien. But I had the stereotypes that come with that label; y'know little green men and all that, so umm.. yeah." Anna exhaled loudly, glad to of gotten it over and done with and she stood there waiting for Alex and Hannah's reactions.

"But, you have a British accent, how does that work?" Hannah asked, Anna was taken aback by the question, it wasn't the response she was expecting at all.

"Well, I was left here as a baby, adopted and raised on Earth, so I'm basically human, I just had parents that aren't 'from around here'." She let out a nervous laugh; still careful as she waited for Alex's reaction. "Okay, I'll admit I wasn't expecting that. Can I ask how S. H. I. E. L. D were able to track you?" Alex finally responded.

"So you're not disgusted or anything? Or even shocked?" Anna head turned between the two of them. Had she found people to trust?

"Well, it was a bit of a shock, but you don't look dangerous and plus you said you weren't the bad guy. So I trust you." Hannah smiled at her and she smiled back, relaxing at the acceptance.

"If only S. H. I. E. L. D saw it that way." Anna sighed but continued. "They are or should I say were able to track me because sometimes I emit electromagnetic rays, that shouldn't be in the atmosphere. Perfectly harmless of course, but annoying for me if they are detected. S. H. I. E. L. D only found me because I was near the area where they managed to trace the rays. I guess they thought I might of seen something. Luckily they had no idea I was what they were trying to find."

"Yes well, they most probably know you're it now." Alex said. "Can you control when you emit these 'rays'?" He was curious and wanted to know more about this intriguing girl standing in his apartment.
"They are only given off by my wings." She chuckled. "But not all the time, just happened to be the wrong place at the wrong time. I played hysterical girl for a while too, made it easier to get away; it's out of character so you are one step ahead with the art of surprise."
"It's difficult isn't it?" Hannah asked as she walked back into the room. Anna hadn't even realised she had left, too engrossed in her conversation with Alex. Her attention turned to the plate in Hannah's hand and what was on the plate. Waffles she thought, that's what I could smell before.
"I thought you might be hungry." She grinned. "I hope you like waffles."
"What did you mean about it being difficult?" Anna asked as she sat down to bite into a waffle she had drowned in sugar.
"I mean being what you are and having to hide it. Aren't you lonely?"
"I have some friends back in London who know about me. S'alright." she shrugged, it did get lonely sometimes but she had gotten used to the feeling.
"So what happens n-" But Alex was cut off by the sound of a phone ringing.
She saw the worried glance the siblings shared then Alex spoke. "That's not mine."
"It's mine." Anna said, getting up to locate the source of the ringing. "It was in my pocket when you found me right?"
"But who's ringing you?" Hannah asked, concern lining her words.
"Let's find out shall we?" Anna picked up her phone; the number was blocked. Typical.

"Hello?"

"You know, beating up agents then running away isn't strong evidence to prove that you don't know anything." The voice was tired and monotone, but it was oh so familiar.

"Agent Coulson, yes? I'm sorry we got off to such a terrible start, things got a little out of hand." Alex and Hannah shifted in their seats, what was she doing?

Alex looked at her and mouthed; 'is it traceable?' She rolled her eyes and shook her head, she wasn't stupid.

"Yes, I apologise for that, but I do believe that it is in both our best interests for you to meet with us."

"And why would I want to do that?"

"You wouldn't want any of your new friends to get into trouble now would you? We can track their car you know, wouldn't be a nice way to repay them for their kindness." at least he didn't know where they were.

"You wouldn't dare! They have nothing to do with this!" By this point in the conversation Alex and Hannah had moved from their seats and were busily typing on their laptops.

"Why don't you come and meet with us and I'm sure we can talk this out like civilised people."

"Yeah right." she scoffed. "Where and when?"

"There is an abandoned warehouse about five miles out of New York, we can send you more details."

"Oohh a warehouse, classy."

"Be there at five P. M, I don't want to have to do this the hard way."

"I thought you already were doing it the hard way?" She was winding him up, may as well have fun in the worst of situations.
She heard the man sigh on the other end of the phone before hanging up. She smirked, then turned to face Alex and Hannah.
"I'm sorry." She said, "I feel like I've dragged you into this stupid mess."

"Hey, it's not your fault. What's the situation?" Hannah asked.

"He wants to meet me. I don't know what they want, but it can't end well." Anna pulled herself up onto the table top, mindlessly watching her legs as they swung back and forth.

"Where do they want to meet you? Can't you just run?" Alex asked.

"Some warehouse outside of New York, they're going to send me more details. And I can't run, they'll track me back to here, I don't want them to find you." She tucked a loose piece of her wavy hair back behind her ear and looked up at Alex and Hannah.

"We'll come with you." Alex stated.

"You can't! You're already deep enough in this anyway, I don't want you to have a target on your heads too." Anna couldn't believe this, she had just met them yet they were willing to stand with her.

"Well, how do you expect to get there? You don't even know where you are!" Hannah replied, her maternal sense kicking in.

Anna raised an eyebrow, she had the quickest way of getting there hidden on her back.

"You're not going to fly are you? Can you even fly?" Alex queried. "You know you are in the middle of New York, you don't want to get shot down or anything. I heard Tony Stark was in town." He smirked, knowing she wouldn't want to have an encounter like that, she was trying to stay hidden.

"Well then, how do you suggest I get there?" She hoped down off the table and fished her phone out of her pocket as it beeped. She glanced at the information on the screen, then chucked her phone at Alex.

"Catch!" He caught it with ease and took in the information, he then handed the phone to Hannah.

"We are taking you, no arguments. We want to help, you can trust us." She looked into Alex's icy eyes and saw no lie in the statement. She could trust him and Hannah, so she did.

"I trust you. Now how long will it take to get there?" Anna replied, gesturing to the phone in Hannah's hand.

"Not long, but we better leave now." Said Hannah, "We better stock up the car though, Alex?" Anna watched as Alex tapped a screen on the glass table, and the cabinet opposite opened to reveal a miniature arms unit.
Anna let out a low whistle. "Impressive." she said.

"Thanks, we designed and built most of the stuff ourselves." Responded Alex as he took out two compact hand guns, a small black backpack and a box of ammunition from the cupboard.
"I see what you mean about S. H. I. E. L. D using your expertise, can I have a look?" Anna pointed to one of the guns. Alex nodded and motioned for her to take it.
It felt heavy in her hands, but not strange, she was familiar with firearms, not that she ever needed to use them. She twisted it around in her hands and let her finger trace along the barrel. Smiling she handed it back to Alex, who placed it carefully in the black bag.
"We better go, you ready?" Hannah asked as she twirled the car keys in her hand.
"Let's do this." Said Anna, smiling.

The car drive was long, and throughout the duration of the journey Anna told Alex and Hannah all about her life as they quizzed her on what she was.

They arrived early, the warehouse and surrounding area deserted. Anna got out first, jumping out slowly and taking in her surroundings. Her pumps landing lightly on the dusty grit. Alex and Hannah followed behind and Anna turned to them.
"There's no one here yet, why don't you go, I'll be fine on my own, they don't need any more of a reason to start a fight."
"Anna, we said we would stay with you, you can trust us." Hannah smiled.
The sound of cars approaching caused them all to turn around. Three black SUV's pulled up and parked about ten metres away from them in a loose triangle shape. Two agents stepped out of each car all of them in black suits except the man in the front, who wore a grey suit and was horribly familiar.
Anna walked up to the man in the grey suit with her hand extended. "Agent Coulson, I'm sorry we couldn't of had a better introduction, allow me to properly introduce myself; my name is Arianna Halverson and I am truly sorry for running away before, but some things I would of preferred to keep secret." As far as introductions went Anna wasn't very good at them.

Agent Coulson smiled at her. "Pleasure to meet you properly Miss Halverson; I see you've acquired some friends." he glanced over the Alex and Hannah before continuing. "We know what you are Miss Halverson, and what you are capable of." She stiffened, how could he know? He couldn't know, S. H. I. E. L. D couldn't of possibly found out! She turned back to face Alex and Hannah, distress evident on her face.

"We want to give you a choice." Anna's head whipped back round to face him. She frowned and he continued talking. "You can either work for S. H. I. E. L. D or we see you as a hostile threat and we must terminate you." He finished and waited for her reaction.
Anna stated blankly at him, okay she didn't know what to expect, but it definitely wasn't that.

"Listen to me, I am not your enemy." She said. "But I can't work for you, this," she gestured to herself, "is unpredictable and dangerous for you and for me."
Now it was his turn to be confused, he frowned and looked at her. "Care to tell me how it is dangerous to you?"
"Can I tell you in private? It's not something I'd like to share in front of certain people.." her eyes darted towards Alex and Hannah.
Coulson looked at her and saw the fear behind her eyes, she was on their side, but she did not want to fight, he needed to find out why. With a flick of his hand his surrounding agents moved away and assisted Alex and Hannah with them, Anna giving them a look telling them it was okay.
Anna took a deep breath and prepared to tell him her biggest secret, only one other person knew this about her, and they were halfway across the world and of no use to her now.
"Well, you see.."

Agent Coulson closed the file on one Arianna Halverson and deleted it off the system, and filed the name away under 'TERMINATED'. He sighed, and waited for his next order, something big was coming for S. H. I. E. L. D.

Arianna stood in the airport departure and turned to face Alex who was staring back at her. "What exactly happened? You never did tell me what you said to him." He asked.

"It doesn't matter, I'm safe now, he saved my life, I owe him." Anna replied.

"As you owe us." Hannah butted in, smirking.

"Well it's a good thing your coming with me then isn't it?" Anna said cheekily.

"Are you sure you're going to be okay Alex?" Hannah asked, concern for her brother showing.

Agent Coulson had let Anna go, but had let the rest of S. H. I. E. L. D believe she was dead. She owed him so much, and now she was going back to London and Hannah was coming back with her. They had bonded so well over the their short time of knowing each other and Anna didn't mind that Alex was letting Hannah go with her as like a babysitter. He wanted her to be careful, he cared about her a lot.
Hannah was going to work with her to produce something big, and hopefully help Anna work on her 'angel' situation.

"I'll be fine Hannah, anyway I hear S. H. I. E. L. D's found something blue and shiny to work on, so that'll keep them busy for a while, hey, they may even need some help." Alex grinned.

"When you say you 'heard' about what they're working on, you mean you hacked the system?" Hannah asked, obviously annoyed.

"Ah, sis, you know me so well." He winked and kissed her on the cheek. "Now hurry up or you'll miss the flight."

"Bye Alex, don't make the big boys too angry." Said Anna and she hugged him goodbye before walking down the the departures tunnel.

A/N: So that's the Prologue to the story, sorry it didn't have that much action towards the end, and don't worry you'll find out everything about Anna soon. I'm not sure how long Chapter 1 will take to be up but it is filled with action and features all the Avengers characters, so look out for it :)