The first time his dad shows Tony pictures of Steve before the serum, Tony is seven years old and he perks up when he recognizes the face.
"That’s him," Tony says, grinning down at the familiar man squinting out at him from the photo. "That’s him, that’s my soulmate, he’s the one in my dreams!"
He looks up at his dad, opening his mouth to continue on about the dreams that he’s been having for as long as he can remember, but he stops when he sees his dad’s expression, and then flinches and runs out of the workshop when Howard yells at him to scram.
Later, he doesn’t know why he had looked up expecting to see Howard smiling. After all, it wasn’t like he ever smiled much when Tony was around.
Unlike most of Tony’s other dreams, which are bright and distracting and have Tony waking up itching for something to write schematics on, the dreams about his soulmate leave him feeling calm. Peaceful. Like everything’s alright.
His soulmate- Steve- Captain America, Tony learns when he gets older- is stick thin and sometimes has a bloody nose when he appears. His clothes are old and torn, he looks like he’s in his early twenties, and he’s nicer than anyone Tony’s ever met.
"When am I going to meet you," Steve asks one day. "And why do you always seem to be getting older, it’s only been a month since I started dreaming about you."
Eleven years old, Tony chews on his lip. He wishes this were one of his maths problems, which he can chew up and spit back out easy as anything, but people, he’s learned, are hardly as easy.
"I don’t think you will meet me," Tony says honestly, and Steve snorts.
"Everyone meets their soulmate, Tony."
Sometime after Tony’s parents die, in the few months after that- he’s not sure what month, exactly- he drifts into an uneasy, drugged sleep.
He’s quiet as Steve tells him that his friend, Bucky, is shipping out tonight, and that he finally, finally got accepted into the Army.
"Are you going to enlist," Steve asks, and then frowns. "Tony? Are you okay?"
The war’s over, Tony wants to tell him. It’s done, we won, you died, Steve, you’re dead.
"You shouldn’t have joined the army," Tony says instead, and Steve sighs.
"Yeah, that’s what Bucky’s always saying. Telling me I’m gonna get myself killed."
You do, Tony doesn’t say, biting his lip so hard it bleeds so the words don’t leak out.
"You never tell me anything about yourself," Steve says one night when Tony’s on the tail end of his twenties.
"I tell you the important things."
Steve hums under his breath. “How long has it been for you?”
He means the dreams. “I last saw you nine months ago.”
Steve makes a face. “I see you every night now,” he says, and Tony thinks, I know, it’s because you have two years to live and they’re shoving all of your Tony-dreams into a short span of time.
Steve pauses before he asks, “Hey, are you- are you related to some fella named Howard? ‘Cause I sorta met him, and he looks a lot like you, and I was wondering if we could be close to meeting, is he your brother or something-“
"We aren’t going to meet, trust me," Tony says, like always, and Steve sighs.
Steve shows up in his dream when Tony’s thirty-three, and when Steve looks down at his body, he barks out a laugh. “Well, okay.”
"I, uh," Steve says, and smiles nervously. "The experiment I told you about? It worked. In reality, I look a lot different now."
Tony tries to look surprised. “Yeah?”
"Yeah," Steve says, fidgeting with his cuffs. "I sorta hoped it’d carry on through to here, but no dice. I look a lot nicer now, I’d have liked you to see me."
"You look nice just as you are," Tony says over a sudden lump in his throat. All his life, he’s been slowly watching Steve head towards his death, and whenever he’s started to tell him, he’s woken up.
Whenever he dreams of Steve now, he wakes up saying words of warning that Steve will never hear, because Tony’s several decades too late.
Steve stumbles into Tony’s dream, gasping and shuddering, gritting out the words, “Bucky’s dead,” and Tony goes cold.
In less than 24 hours when Steve wakes up from this in his time, Steve is going to be at the bottom of the Atlantic, and Tony’s seen this play out in history books so many times his head hurts with it.
He tries to say, “Don’t chase the Red Skull, don’t do it, find some other way, live and come and find me-“
He wakes up after the first word.
Tony doesn’t see Steve after that, and he tries to find a case, any case, where soulmates are born this far apart: where one of them dies decades before the other is even born, and comes up with nothing.
Afghanistan happens, and Iron Man happens, and Tony dreams his usual dreams and goes to Captain America exhibits and tries not to think about the guy who used to frequent his dreams, cold and alone under the ocean.
When it happens, when he gets the call about Captain America, he’s not even surprised. Instead he lets out this absurd little giggle that barrels into a laugh, and then he’s on the floor crying with it until Pepper takes the phone away.
He tells Pepper about the dreams on the way over to SHIELD, and Pepper stares at him with wide, tired eyes before starting to giggle, which leads to both of them having a laughing fit, and by this point Tony’s stomach muscles ache from it.
Someone tries to stop them from coming in, but Tony pushes past him. “It’s okay, Steve’s expecting me,” he says, and when he enters the room, Steve’s head is turned towards his voice.
Steve’s lips part when he sees Tony, face going slack with surprise.
"Hi," Tony says, voice cracking. He clears his throat, tries again. "Uh, hi, I’m Tony."
"I know," Steve says, sounding equally shaken. His tongue comes out to wet his lips. "You never mentioned- all of this. The plane."
"Anytime I tried, I woke up," Tony says. "Sorry."
"It’s okay," Steve says, sounding drunk, sounding concussed, sounding confused and stunned and- hopeful. "I- it’s good to meet you, finally."
"Finally," Tony echoes, and something clicks into place when Steve touches his arm, squeezes it once- they can’t touch in the dreams, it’s reassuring to finally have each other solid in front of them.
Steve’s smile is flimsy. “Sorry I kept you waiting, I guess.”
"It’s okay," Tony says, and it is, they have the rest of their lives to make up for lost time.