AN:- Haven't forgotten this, it's just going to be a very slow burn sort of story.

Chapter 1: Assemble

The harsh smack of a hand hitting flesh echoed through the warehouse.

It was midnight, and in a darkened room four men gathered around a woman tied to a chair. The woman was wearing an elegant black cocktail dress, and her hair and makeup had been artfully done before the beating she had endured. One of the men stepped forwards. He was older than the others, wearing a double breasted pin-striped suit. He brushed some imaginary dust off the fedora he carried as he walked closer to the woman.

"This is not how I wanted this evening to go." He spoke Italian, in a deep heavy voice.

The woman in the chair forced her head up, peering at him through matted hair. "I know how you wanted this evening to go. Believe me, this is better."

He grinned at that, but it was an ugly look on him. "Who are you working for? Lamberto, yes? Does he think we have to go through him to move our cargo?"

One of the thugs grabbed the chair she was tied to and dragged it back to the edge of the floor, holding her over a twenty foot drop straight down onto the factory floor. "I thought Salomone is in charge of the export business?" She said, panic creeping in as her feet scratched to find the floor.

"Salomone?" The gangster laughed, his men joining in. "A bagman, a front. Your outdated information betrays you." He gestured for the thug to bring her chair back, still chuckling. "The famous Black Widow, and she turns out to be simply another pretty face."

She was still breathing heavily, head twitching like a frightened rabbit. "You really think I'm pretty?"

The leader walked over to a table nearby that had several tools spread out on it. "Tell Lamberto we don't need him to move the booze." He discarded a wicked looking pair of shears and started checking the hammers. "Tell him he's out." He finally settled on a pair of pliers. "Well…" As he turned back he switched briefly to heavily accented English. "You may have to write it down."

Just at that moment a ringing phone interrupted the scene. It was so absurd that for a moment they all just stared at it. Then one of the thugs walked over and picked it up. "Who is this?"

A second later he held the phone out to his boss, confusion plain on his face. "It's for her."

The gangster grabbed the phone and held it to his face. "Now you listen carefully-"

"You're at 156 Northern Jefferson, third floor. A box of explosives has just been placed downstairs. Put the woman on the phone, or I will blow up the block before you can make the lobby." The voice was calm and collected, and his words didn't sound like a threat. They sounded like a personal promise. The gangster nodded, his bluster vanishing, and waved for them to drag her chair over to the phone.

The receiver was shoved hard against her ear and she glared at the thug holding it. "What?"

"We need you to come in."

"Are you joking sir?" The faint Italian accent she had had all night suddenly vanished. "I'm working!"

"This takes precedence."

"I'm in the middle of an interrogation and this goof is giving me everything."

"I didn't…" He was silenced with another glare, finishing the rest to his men. "Give… everything."

Widow was ignoring him, still talking to the man on the phone. "Look, you can't pull me out of this right now."

"Natasha." With the use of her real name she frowned deeply. "Barton's been compromised."

"Let me put you on hold."

The thug holding the receiver took it away, but before he could place it back on the cradle she kicked out hard, catching his knee and breaking it. He yelled and dropped to the floor as she tipped the chair sideways, landing hard on the concrete. The flimsy wood shattered and she rolled free, the rope binding her hands already long undone. She rolled over the man on the ground, ignoring his pained screaming, and reached under his jacket to grab a pistol from his shoulder holster.

The other men were slow to respond, and she shot one of them in the chest before he could even move. The second two both drew revolvers from their waistbands and fired, missing completely. Natasha took careful aim and shot the second bodyguard in the neck. He dropped to the floor trying to staunch the blood flow. The leader of the gangsters tried to run but she put a bullet in the back of his kneecap. He went down screaming.

She ignored the whimpers and groans around her, grabbing the phone again. "Where's Barton now?"

"We don't know."

"But he's alive?"

"We think so. I'll brief you on everything when you get back. But first, we need you to talk to the big guy."

She sighed, taking the pistol apart and throwing the spare bullets down the hole in the middle of the room. "Coulson, you know that Stark trusts me about as far as he can throw me."

"No, I've got Stark." She would almost have believed Coulson was smiling. "You get the big guy."

She replaced the receiver slowly. Looking around the room she allowed herself one unprofessional outburst. "Mein Gott."

/|\

On the Mexican border a train rumbled past a broken down shack. A young Mexican girl waited for it to pass before sprinting across the track and heading for the shack. In her fist was clutched a wad of bank notes covered in dust and grime. Her skin was dark, her dress ratty, her feet bare and her hair knotted and dirty. She looked like any other urchin.

She raced into the shack and held out the notes, chattering in rapid Spanish. An older woman turned and waved her away.

"Who are you? Get out, there is sickness here!"

The girl continued to speak, her voice high and scared. A man stepped from the back room, pulling off a blood stained apron and throwing it into a bin. He crouched down and spoke to the girl directly, low and quiet.

"Please, slow down." His voice was kind, and his eyes were big and warm. The girl calmed quickly.

"My father."

He nodded, looking back to the room he had just left. There was no door, and through it could be seen a couple of mattresses on the floor, currently occupied by very sick looking men. "Like them?"

The girl nodded, holding out the wad of notes again. "Please," she said in heavily accented English.

Doctor Bruce Banner sighed and straightened, collecting a small leather bag from the nearby table. In his heart of hearts he knew there was little he could do for the little girl's father. Spanish Flu was fatal in nearly every case after all. But he could at least help. He followed her as she scampered out into the night, trying to keep up as she ran further outside of town.

He was the only gringo in town, and that night he was the only man in a suit as well, dishevelled and crumpled as the suit was. He kept to the shadows as they ran through the town, trying to avoid anyone who might not be too happy to see him. More than a few of the locals didn't take too kindly to having a white American invading their town. And there was always the possibility of a Pinkerton on his trail.

They came out to the very edges of the town, where shack would have been a positive description of the dwellings people lived in. The little girl seemed entirely at home, slowing a little as she entered familiar territory. The shack she led him to was out of the way even by the standards of the other shacks. Right alongside the train tracks and shielded on almost every side by trees.

He followed her through the front door only to find that she was crawling rapidly out through a small hole in the opposite side of the house. There was nothing inside but a small table and a chair, a woman sitting in to with her back to him.

He shook his head, straightening and stepping fully inside, closing the door behind him. "Guess I should have got paid up front."

"You know." Her voice had no discernible accent. And despite sticking out even more than Banner in the surroundings she was entirely calm. "For a man who claimed he was avoiding violence, you picked a hell of a place to settle." She turned to reveal pale skin artistically framed by dark red hair. He couldn't tell if it was natural, but he suspected not.

"I never said I was avoiding violence."

"Then what is it?"

He smiled, but it looked more like a grimace. "You brought me to the edge of the city, smart." He moved to the other side of the table from her. "I uh...assume the whole place is surrounded?"

The woman smiled at him. "Just you and me."

He nodded, taking in the elegant black cocktail dress she was wearing, a shawl across her shoulders and a small handbag on her left arm. If he had any reaction to her beauty it was well hidden. "Your actress buddy." He nodded to the hole she had crawled through. "Is she a spy too?"

The woman nodded once.

"Do they start them that young?"

"I did."

"So who are you?" He was rubbing the strap of his bag.

"Natasha Romanoff."

"Are you here to kill me, Miss Romanoff?" His grip tightened on the bag. "Because that's not gonna work out for everyone."

"No. No. Of course not." She stood and smiled, a brilliant flash of white teeth. "I'm here on behalf of SHIELD."

He closed his eyes for a moment and his jaw jumped as his teeth gritted. "SHIELD. How did they find me?"

"We never lost you, Doctor. We've kept our distance, even helped keep some other interested parties off your scent."

"That would explain not seeing the Pinks. Why?"

"Major Fury seems to trust you. But now I need you to come in."

He had stopped fidgeting, and somehow the calm seemed to spook her more. "What if I say no?"

"I'll persuade you."

His smile told her that she would be unwise to try. "And what trouble do you expect me to get into."

She took a file from her bag and laid it out on the table. He flipped it open.

"This is-"

"I know what this is." His tone kept her quiet as he flipped over the picture.

The silence dragged on until it became deeply uncomfortable. Finally she spoke again.

"Doctor, we're facing a potential global catastrophe."

"Well, those I actively try to avoid." His good humour had only appeared to return. The stress was plainly evident in the deep lines around his eyes. "What exactly does Fury want me to do? Make him some more?"

"He wants you to find it. It's been taken. There's no one that knows this compound like you do." She shrugged. "If there was, that's where I'd be."

"So Fury isn't after the monster?"

"Not that he's told me."

"And he tells you everything?"

"Talk to Fury, he needs you on this."

"He needs my knowledge?"

"No one's going to ask you to-"

He slammed his bag down hard on the desk, pulling the catch open. "Stop lying to me!"

She moved like lightning, a gun appearing from her purse and training on his head in a split second. Her hands shook slightly but the muzzle of the gun didn't waver.

Banner let go of the bag and stepped back, keeping his palms open and facing her. "I'm sorry, that was mean." His grin was firmly back in place, but she didn't lower the gun. He could see fear in her eyes. "I just wanted to see what you'd do." He slowly opened the bag to show nothing but medical supplies inside. "Why don't we do this the easy way, where you don't use that, and the agents outside don't make a mess? Okay? Natasha?"

She slowly returned the pistol to her bag, drawing out a short wave radio. "Stand down. We're good here."

From outside they heard the sounds of guns being uncocked. Banner cast a glance to the front door, then back to Natasha. "Just you and me?"

/|\

The bag thumped rhythmically with the repeated impacts of fists. The gym was empty of all but one man, tall, broad in the shoulder and narrow at the hip. His blond hair was sweat soaked as he pounded again and again at the heavy bag. It rattled on its chain again and again as the tempo increased, the force of the punches heightening as the man attacked it with everything he had.

He had short blonde hair, cut military style, and a well-defined jaw. His eyes were the greying blue of the sea in a storm, and as he increased his speed and rhythm again lines crept in at the edges. Everything in his face, his stance, his motions, his eyes, all suggested tension, pain concealed deep beneath the surface.

At last his punches abated and he leaned against the bag, breathing heavily. With a final punch he stepped back and headed for his gym bag.

"Trouble sleeping Captain?"

He looked up to see Fury standing in the door of the gym. He wore a midnight blue suit with a dark tan overcoat, and was once more toying with his hat.

The captain started to unwind the tape from his fingers. "I slept for ten years, sir. I think I've had my fill."

Fury strolled into the room, examining the bag. "Then you should be out. Celebrating, seeing the world."

The captain shrugged, stuffing shirts into the bag and lifting it onto his shoulder. "I went under, the world was at war. I wake up, they say we won." He took a deep breath and looked around the gym as well. "They didn't say what we lost."

"We've made some mistakes. Some very recently."

"You here with a mission, sir?"

"I am."

"Trying to get me back in the world?"

Fury produced a file from under his coat. "Trying to save it."

Opening the file revealed a small picture of a metal ball. "I remember this sir."

"In 1913 a scientist and doctor by the name of Bruce Banner invented a new type of explosive. It was more powerful than dynamite and TNT, it was stable enough to be transported without fear of detonation, and could be used in our new line of explosive shells. He had even perfected a liquid form which was used in our flamethrowers."

"Sounds like an upstanding man."

"Banner didn't agree with the way the United States government made use of his invention. He had imagined it would be used for building and mining purposes, and in stable liquid form could even serve as a new form of fuel he termed 'rocket fuel.' He envisaged a bold new frontier of scientific advancement."

"But you continued to work on it?"

"Development was handed to my department, where I authorised testing into its capacities as fuel. We had almost the entire world stockpile." Fury turned back to look at the captain, lighting a cigarette. "Unfortunately someone decided to take it from us."

"Who?"

"He's called Loki." Fury puffed out a cloud of smoke. "He's not from around here."

The captain nodded, setting the file down and picking up his gym bag again.

"There's a lot I'll need to know."

"Agreed." Fury crushed out his cigarette and followed the captain out. "The world has gotten even stranger than you already know Rogers."

"At this point, I doubt anything would surprise me."

"Five bucks says you're wrong."

At the top of the stairs Fury held open the door to reveal the same black car he had driven in Massachusetts. "There's a debriefing package waiting for you. But your personal experience with the explosive will of course make any insights you have useful."

Rogers stepped into the car and rested his bag on his knees. "What happened to Banner?"

"He went AWOL during the war. We haven't seen him since."

"Maybe he had the right idea."

/|\

Hidden deep in the bowels of a building a man wrestled a wrench into place. From outside the wall a woman's voice shouted through to him. "We're ready to go on this end."

The man shoved the wrench around a quarter turn, connecting a fuel line. It started to rumble as fuel poured through. "Are we off the grid?" he shouted over the racket.

"Stark Towers is about to become self-sufficient."

"Light her up."

There was a deeper rumble from inside the building and the man started to wriggle his way out of his confined position. Outside he walked directly to a window and looked out to see a big neon sign flicker to life. Stretching across the front of the office building it spelled out 'Stark.'

A blonde woman came up behind him and wrapped her arms around his waist. "How does it look?"

"Like Christmas, but with more...me." He leaned his head back to rest on her shoulder. She was slightly taller than him, willowy and beautiful. He was stocky by comparison, well built and with a neat moustache.

"You have to go wider on the public awareness campaign," she said, stepping back and heading over for the desk in the middle of the room. "You need to talk to the press."

He nodded and came over as she carried on talking, flipping through piles of papers. "I can do some more tomorrow; I'm working on the zoning for the next billboards."

"Pepper, you're killing me. Remember? Enjoy the moment?"

She looked up and smiled. "I remember."

As she walked back round the desk towards his open arms a man appeared in the doorway, clad in a formal dinner jacket and waistcoat, his blonde hair neatly combed down as he snapped his heels together. "Sir, Agent Coulson of SHIELD is on the telephone for you."

Stark kissed Pepper on the cheek and spun her round so they both faced the butler. "I'm not in." He kissed her on the back of the neck, giving his dogsbody a pointed look. "I'm actually out."

"Sir, I'm afraid he's insisting."

"Hang up the phone Jarvis. I got a date."

Jarvis nodded smartly and exited, leaving the two to kiss again as Stark led the way over to a large leather couch. "So how does it feel to be a genius?"

Pepper allowed herself to be drawn down onto the sofa, where Stark poured her a glass of champagne. "Well, ha, I really wouldn't know now, would I?"

"What do you mean? All this," he gestured at their opulent surroundings. A massive crystal chandelier hung above them, and everywhere there was rich mahogany and gold inlay. "Came from you."

She shook her head. "No. All this." She waved at the room as well, then pointed to a metal box in the corner of the room. "Came from that."

"Give yourself some credit, please. Stark Tower is your baby. Give yourself, twelve percent of the credit."

She pushed away from him and raised an eyebrow. "Twelve percent?"

He shrugged. "An argument can be made for fifteen."

She put her champagne down. "Twelve percent for my baby?"

"Well, I did do all the heavy lifting." She stood and headed back for the desk as he chased after her. "Literally, I lifted the heavy things. And sorry, but the security snafu? That was on you."

She started to sift through the papers again. "You mean our elevator?"

"It was teeming with sweaty workmen." He rested against the desk as she found the file she was looking for and started to read it, ignoring him. "I'm going to pay for that comment about percentages in some subtle way later on, aren't I?"

"Not gonna be that subtle."

"I'll tell you what." He covered the paper with his hand. "Next building is gonna say 'Potts' on the tower."

She looked up. "On the lease."

He pulled his hand back and hissed through his teeth. "Call your mom, can you stay over?"

Jarvis was at the door once more. "Sir, Agent Coulson. I'm afraid-"

"Jarvis, what did I just-"

"Stark, we need to talk." The grey suited man had emerged from behind Jarvis, and he didn't look amused.

"Security breach," Stark said immediately, pointing to Pepper. "That's on you."

"Mr Stark."

Pepper was standing and smiling as she came round to give Coulson a brief hug. "Phil! It's great to see you again.

Stark looked utterly nonplussed at the events unfolding in his office. "Phil?"

Coulson and Pepper were still talking. "I can't stay."

"His first name is Agent," Stark protested lamely.

"Come on in, we're celebrating."

"Which is why he can't stay." Stark came to stand next to Pepper, putting a hand around her waist.

Coulson produced a manila wallet from behind his back and held it out.

" I don't like being handed things"

"That's alright, cause I love to be handed things." Pepper took the folder and handed Coulson her glass of champagne before giving the folder to Stark in exchange for his champagne.

"Official consulting hours are between eight and five every other Thursday." Stark headed back to the desk, opening the file and pulling out a blurry photograph or a military unit.

"This isn't a consultation."

"Is this about the Avengers?" Pepper coughed and looked away as Coulson gave her a raised eyebrow of his own. "Which I...I know nothing about."

"The Avengers Initiative was scrapped, I thought," Stark said from the desk. "And I didn't even qualify."

They were all heading for the desk now as he continued to take out photographs, including one of a man in a labcoat and a beaming smile as he presented a small vial. "I didn't know that either," Pepper said.

"Yeah, apparently I'm volatile, self-obsessed, don't play well with others."

"That I did know."

Coulson smiled. "This isn't about personality profiles anymore."

"You know, I thought we were having a moment Miss Potts."

She finished her drink and put the glass on the desk in front of him. "I was having twelve percent of a moment." She walked round the desk to look at the file with him, leaning close to whisper in his ear. "This seems so serious, Phil's pretty shaken."

"Why is he Phil?"

"What is all this?"

"This is uh..." He took out an image of a hollowed out shell of a building. "This…" Another picture, this one of a city street that had been almost entirely flattened by an explosion.

"I'm going to take the flight to D.C. tonight."

He looked up sharply. "Tomorrow."

"You have work." There were at least a hundred more photos in the file. "You have a lot of work."

AN:- Couple more revisions from the original to try and make it work in a 1920s setting with no magic or sci-fi.

Natasha is now a German double agent, not Russian. Russia weren't exactly allies in the 1920s, but they also weren't the absolute enemy in the way that Germany was. Here she's also not interested in the illegal arms trade, but in the Italian mob moving illicit alcohol. This whole setting is obviously sometime during Prohibition, meaning that in this instance SHIELD was perhaps supposed to be an agency more like the proto-FBI or the Bureau of Prohibition (famous for being the home of the Untouchables.) I couldn't think of a way to have the F-22 bit so instead just imagine one of the SHIELD agents dumped a box of explosives in the lobby before running.

Obviously the biggest change is in Bruce Banner, who is not going to turn into an enormous green rage monster when he's stressed. I have decided instead to give him a backstory similar to Alfred Nobel, the inventor of dynamite in 1867 and founder of the Nobel Prize in 1895. So for this story Banner invented a new type of explosive which did all of the nifty things Fury says it does here. However as a medical doctor he was horrified when he saw his invention being put to destructive use in the First World War, which caused him to go AWOL and flee to Mexico to do good works to try and redeem himself. This also actually ties in to Cap's backstory. He was put into a coma for ten years sometime in 1917/18 until 1927/28, which funnily enough would be about when the Untouchables came into being (1929) and the real fight against the Prohibition era gangsters came into effect (obviously not helped by the Depression hitting in 1929) This story is then set sometime in 1927-28, pre-Depression, which is why Stark can still be building his big old tower.

Final change is to Stark, who did not fight in the war and was not injured by a shrapnel attack. Instead he was injured in a chemical weapons attack while selling arms, which now necessitates his use of an iron lung on a regular basis to keep his breathing regulated. He doesn't need to wear it all the time, but he would need to wear it if he was going to exert himself in almost any way. The innovative genius part comes from the fact that he managed to make the iron lung portable. I'll go into more detail later but basically he has a metal backpack that holds the motor, pumps and valves, tubes which lead over the shoulders to what is basically a gas mask. The miniaturisation (relatively speaking) of the motor is what helped Stark towers becomes self-sufficient energywise. So it all sort of ties into the MCU canon while still being period appropriate (first medical use of a modern iron lung was believed to be about 1928), plus actually makes the 'Iron Man' nickname entirely appropriate. Also also he'd look like some sort of badass dieselpunk hero with a metal breastplate and awesome gas mask design.

I have had to do so much research into 1920s era technology just to see what was and wasn't possible at all back in those days.

And of course this all necessitated a couple of changes to the dialogue to make it all gel but hopefully it's all still feeling like the movie, just in a different time period.