Note: I'm working off of Chris Evans' version of Johnny Storm, not the new one, so we have the glorious thought of Evans twins. And man that's an attractive thought.
Timeline
June 1943 about a month before, Bucky and Johnny leave for their respective units and Steve starts basic training
June 1943 Steve joins USO
November 1943 Steve rescues the 107th
June 1943
"Stevie, please try to stay outta trouble. You hear me?" Jonathan Rogers told his little brother in the spare moments they had before he would have to leave to work on a military testing site. He wasn't about to tell his little brother that the reason he was going to earn so much money was because he would become a human test subject for the cryofreeze tank that the United States government was working on.
Steve Rogers smiled up at his twin, "How can I get in trouble when you're taking all the trouble, Johnny, and Bucky's taking all the stupid?"
Johnny fondly ruffled Steve's hair, "Just try to be good, huh? We won't be there to mother hen you no more."
Steve turned his watery smile onto his brother, "I'll do my best. Promise."
The twins shared one last hug, neither knowing that would be the last contact they would have with each other until 2013. Johnny smiled once more at his brother before turning and getting on the train bound for some testing facility in the middle of nowhere. Steve left the station as soon as his brother was safely on board. Neither twin looked back.
While Steve is in a container becoming Captain America, Johnny is stepping into a cryo container for the six month testing. "You sure about this son?" A general asks Johnny.
Johnny nods, "Sure. Just like taking a nap."
The general shakes his head as his signals for the container to be sealed and the freezing process to begin. As Steve steps out of his container, Johnny's finishes the freezing sequence.
July 1943
"Let's hear it for the Star Spangled Man with a Plan!" The announcer called as Steve made his final bows. Steve waved awkwardly at the crowd before disappearing backstage and into the heavily perfumed dressing room. Steve sighs as he pulls out the lone photo of him, Bucky, and Johnny. Hearing the girls filing back into the dressing room, Steve shoves the picture back into place and grabs his stuff to go change in the men's restroom.
Three states over the testing facility Johnny's being held at is hurriedly being evacuated. "But sir!" A medical advisor calls towards the general, "The testing men are still inside!"
"They're dead men either way!" The general calls back, "Now get a move on before the damn Nazi spies kills us all!"
Johnny and four other men are left frozen in cryo chambers and the base will not be touched for decades.
April 2008
"Hey Ben, Reed, come look at this!" Sue calls out to her companions as they wander around the old abandoned military base.
Reed had recently bought the property and the three were looking around to see what about the building was salvageable. "Please tell me this is not what I think it is." Reed says in horror.
Sue shakes her head, "It's really five men frozen in what seem to be cryo chambers. From what I gathered from the military files, this place hasn't been in use since World War Two. We're probably the only people alive who know this is here."
"Do you think they're alive?" Ben grumbles.
"Who knows. They might not be." Reed replies.
"Should we unfreeze them? Just to see? Or would that be cruel, bringing five guys from almost seventy years ago into the modern times?" Sue worriedly asks.
"I vote we unfreeze them just to see if these things work." Reed says.
Ben and Sue mumble their agreements. Three months later, hospital equipment in place and a fully functioning building later, the three go into the cryo chamber room and start the process of opening the chambers one by one. The first four men were dead and they take care to bury their bodies. As they waited for the last chamber to open, Sue murmurs, "He's going to be dead too, isn't he?"
Reed places a comforting hand on her shoulder, "It's best not to get our hopes up."
Once the chamber is fully opened, the three move the body to the medical room to examine the body. "He's alive." Sue whispers in awe, "He's alive! Reed, Ben, he's alive!"
The other two quickly double check Sue to find that it wasn't just her imagination. "It's incredible!" Reed says, "How is he even alive?"
Time passes and one day, weeks later, the man wakes up. Sitting up, he speaks for the first time since 1943, "Toto, we're not in Kansas anymore."
"Hi!" Sue rushes forward, "My name is Sue, and those are Reed and Ben. What's your name?"
"Jonathan Rogers. What year is it?"
"Jonathan, it's 2008." Sue gently says.
"What?" Johnny looks mowed over. "You're not just yankin' my chain?" Sue sadly shakes her head. "What about the other men?"
"You're the only one to make it." Sue continues her soft tone. "I'm so sorry."
"How?" Johnny breathes in confusion, "Dammit, how?!"
"We don't know. This place has been vacant since July 1943. Supposedly Nazis spies were attacking the place."
Johnny shakes his head, "What am I going to do?"
"You can stay with me." She softly says to Johnny, "I'll set you up with an identity and I'll help you get used to the times, right along with Reed and Ben. You could be my little brother."
A rueful smile played on Johnny's lips, "I'm afraid I only know how to be a big brother."
"I don't know how to have a brother at all, we can both learn." Sue smiles, "Now c'mon, Jonathan, let's go get you a shower."
"Johnny."
"What?"
"Only my Ma and my little brother, when he was real mad, called me Jonathan. I prefer Johnny."
Sue nods, "Sure, Johnny."
Johnny gave Sue a sad smile as he followed her to the showers.
July 2008
"Steve Rogers and Bucky Barnes died in action during World War Two? Part of the Howling Commandos?" Johnny asks Sue one day.
Sue nods, "That's right. Captain Rogers was subject to a drug and vita rays that transformed him into Captain America. Every child in America knows of him and his Howling Commandos. Did you know them?"
Johnny looked pained, "Remember that little brother I mentioned?"
"Steve was the little brother." Sue stated.
Johnny looked miserable. "He was, the brave little fool."
"I'm sorry."
"'S'okay." Johnny silently walked out of the living room of Sue's house and into his room. Sue didn't see him again for a week.
Four years later
"And now we're only waiting on the Fantastic Four to arrive before the debrief." Phil smiled at the gathered Avengers.
Steve gave Phil a strained smile in return before turning back to the history book he had perched in his lap. A few minutes later three people calmly walked into the room. "Aren't there supposed to be four of you?" Tony quipped, "Where's matchstick?"
"He's just running a few minutes late." Sue defended the man she quickly had come to see as her little brother.
As mentioned, a few tense moments later a tall, blonde man came striding into the room, his signature smirk firmly in place. "What's shakin' Tin Man?"
Steve's head snapped up in shock, "Johnny?" He blurted out before he could stop himself.
"Stevie?" Johnny asked, equally shocked.
Steve stood up and hesitantly walked over to Johnny. Once the two stood side by side, the resemblance was uncanny. Steve threw himself at his older brother, clinging on for dear life as he shook with silent sobs. Johnny held on equally as tight, tears running down his cheeks. Johnny ran his hand through Steve's hair as he made soothing sounds. "I'm alive. You're alive. We're good, it's fine."
A few minutes later the two pulled apart. Johnny grinned at his little brother, "Finally caught up to me, huh pipsqueak?"
"Shut up, gigantor."
"Aw, Stevie, look at us, two devilishly handsome men crying like a coupla kids."
Steve laughed, "I thought you were dead, you jerk! I'm allowed to cry. Besides, they were manly tears."
Johnny giggled, "Sure, uh huh, manly tears." Johnny sobered, "I thought I woke up in the future without my little twerpy brother. We're both allowed a few tears."
"I've missed you." Steve mumbled.
"Aw, you've missed me. I mean, I am the more attractive twin so I can understand why you would miss me." Johnny joked, overjoyed when he finds Steve smiling once more.
"You just wish you're smarter." Steve poked fun at his brother, "I mean, it must be hard to be blonde and dumb as a rock."
"Hey!" Johnny pinched his brother, "Little twerp! I am not some dumb blonde! Besides, you're blonde too, s'not like it's hardly an insult!"
Steve chuckled, "I may be blonde, but at least I have brains with my brawn!"
"You're so going down!" Johnny jumped Steve, crashing them both to the floor in a tangle of limbs.
Sue smiles broadly, happy her little brother go to be with his little brother again. After a few minutes of the two wrestling, she gives out a sharp whistle, breaking the two apart. "On your feet boys!"
Johnny and Steve scramble to listen to the command that sounded so much like what their ma used to. Johnny threw his arm around Steve's shoulders, awkwardly tucking Steve against his side. Steve pushed away from under Johnny's side, but allowed his twin to keep his arm around him.
"I'm Sue, the one who found your brother." Sue holds out her hand for Steve to shake.
Steve happily shakes her hand, "Thanks for taking care of the big lug, I know he can be a handful."
Johnny snorts, "Look who's talkin'."
Sue and Steve ignore Johnny, "I got him an identity as my little brother: Johnny Storm."
Steve snickers, "Look how the tables have turned."
"Shut up, punk." Johnny grumbled good naturedly.
"Who knew Cap was such a child at heart?" Tony laughed.
Johnny burst out laughing, "What? You believed the bullshit about Stevie being a saint? He's a goddamn menace."
"Only to you. I have a reputation as a little brother to uphold. There's a creed 'n everythin', I promise."
"You are such a fuking liar." Johnny gives Steve a look.
Steve gives his brother an innocent look, "Am not."
"Are too."
"Am not."
"Are not."
"Are too- Damn it Johnny!" Steve glared, "You're such a fucking asshole, ya know that?"
Johnny preened, "Don't mess with your big brother."
Tony gasps, "Captain America knows how to swear!?"
"I was in the fucking army." Steve calmly states, Johnny broadly smirking to his side.
"And Brooklyn wasn't some high and mighty neighborhood. We mighta been raised by Sara Rogers, but we were swearin' somethin' fierce by the time we were thirteen."
"Got our mouths washed with soap a coupla times for it too." Steve grumbles.
"'Cause you're a goddamned idiot." Johnny fondly tells his brother.
Steve gives his brother a dirty look, "Was your fault."
The Avengers and remaining Fantastic Four smirk at the scandalized look that graced Phil's face. Fury looked like he was going to blow a gasket, "I swear to god if you two start to cause trouble because the dynamic duo got back together."
"Oh we'd never cause trouble, sir." Steve innocently says.
"Uh huh, want to tell me that again and mean it?" Fury grumbles.
Johnny smirks, "Oh we promise not to make too big of a mess."
"Just a few harmless pranks is all, sir." Steve continues, "Nothing that would really hurt anyone."
Johnny nods sagely, "We only maim, never kill."
Steve's innocent smile turns into helpless giggles as he clutches onto his brother for support. Johnny finally breaks and laughs along with Steve. "God I've missed this."
"We are actual five year olds." Johnny comments through giggles.
"Basically." Steve agrees.
The group, barring Fury, watches in amusement as two large, blonde superheros collapse against each other with giggles. "I'm not paid enough for this." Fury grumbles, causing the twins to laugh even harder.
Eventually the two settle down enough to hold the meeting. Immediately after the conclusion of the meeting, Johnny and Steve race out of the room. Steve calls back to his team that they're going out for dinner and to only call him if it's an emergency. Johnny just waves at Sue and pulls Steve along behind him.
Soon after the two leave the SHIELD facility, pictures begin to be posted to social media; the twins with their arms thrown around each other giggling, them hunched over their food and wide grins gracing their mouths, a video of the twins playing some sort of demented frisbee in the park.
"Goddamn it." Fury grumbles, "Now we'll have to hold a press conference or something. Phil, set up an interview with Ellen. I'm sure she can handle those demented twins."
Phil, still in shock from the whole ordeal, simply nods and walks out of the office to get started setting up the interview time.
"Goddamn Rogers men coming back from the dead to ruin my perfectly laid plans. Why did Rogers have to be related to Johnny Storm of all people. Of all the people in this entire world, it had to be Johnny Storm." Fury continues to grumble to himself as he works on his foot-high pile of paperwork. "Goddamn World War Two soldiers."
