Maybe he should have seen this coming.

He'd spent weeks at a time chasing cold leads with Sam, felt the sting of guilt when he was called off his personal mission to help fill in the gaping security hole the fall of S.H.I.E.L.D. left in the world. Sam knew. Sam understood. He was the unknown in their duo, unexpected and unassuming, whereas Steve was the public face, the man who brought down S.H.I.E.L.D. Steve was needed elsewhere.

Either to ease the burden of guilt from bringing down what good the organization had done or to reaffirm that he, Natasha, and Sam had done the right thing by cleaning up the mess that remained, he's not sure.

Natasha's been elsewhere, finding herself. Reinventing herself. Steve knows that, too.

He just hadn't seen her finding herself with Banner.

He notices it first when they come up with their lullaby pattern, a hypnotism to ease Banner out of the Hulk: gentle words, gentle hands, gentle music on the Quinjet home. It's hypnotizing to watch, but he sees a tenderness in Natasha's eyes that he's only seen once before: just before she kissed him goodbye in the graveyard.

Maybe he was foolish to think it meant something more.

So Steve takes a step back. He says nothing on the matter, it's a quiet step back from her life. When she comms him for pizza and a movie in her quarters, he politely declines. Their sparring sessions become less frequent. He just doesn't want to step on anyone's toes. He sees the quizzical tilt in her head when he starts calling her 'Romanoff' again and he admits to himself that it feels foreign on his tongue. She hasn't been 'Romanoff' in years, always 'Natasha' - more recently 'Nat'.

He feels the strain from their friendship start to wear on their working relationship and wonders if she feels it too.

She starts to rely on Barton again in the field. He finds that Thor makes a formidable partner.

When Steve sees Natasha and Banner flirting at the bar, he puts on a good face. He knows Banner by now, fairly well on a personal level and a lot on a working level. He's a good man and he hasn't had a good decade. He's a good man who deserves some happiness. If Natasha makes him happy, well… Steve will be happy for them.

It doesn't mean he doesn't put in a few parting shots when he gives Banner his blessing. "I've seen her flirt. Up close."

And maybe he doesn't just mean Peggy when he gives advice about waiting too long.

When they're on the Quinjet, coming home from South Africa and still reeling from the Maximoff girl's mind tricks, Steve lets himself watch her from time to time. He hasn't seen her shaken by much, but whatever the Maximoff girl had done must have hit Natasha good. And if it's anything like the visions he had, he doesn't blame her.

"Hey," he says quietly, when Tony's stretched out on a bunk, snoring softly, and Banner's curled on the floor. Thor's watching the sky while Clint flies them home.

She barely lifts her head in acknowledgement. "I'm fine, Rogers."

It stings when she uses his surname, but it's a fair return. "You should sleep," Steve tells her.

She snorts derisively. "Oh, now you're concerning yourself with me…"

He's tired and his head aches like it hasn't since he woke up in a hospital bed thirteen months ago with only Sam at his side. He doesn't feel like figuring out what her words mean or why there's so much bitterness in them. "Captain's orders," he says instead, his tone final.

He misses her. Them. The easy banter between them, the fluidity of how well they worked with and around each other. He still trusts her with his life, could never not trust her again after the sacrifices she made for him, but he wonders if he's damaged her trust in him.

So chopping wood at Barton's farm seems to be a good way to work out his aggravation with her, and with himself. (He'll consider this new information about Barton's family later, when he's not so preoccupied with keeping them from dying.) It's certainly a distraction from the memory of the easy way Natasha had hugged Lila and Cooper, or the way she'd easily conversed with Laura and her obvious baby bump.

Maybe that's why he's so callous in Seoul when Clint asks for visuals, but he knows he's got seventeen other problems to deal with (two of them are genetically modified turncoats that need firm handling). Maybe he should have paid closer attention to the strained tone of Clint's voice when he asks if Steve sees Nat, and maybe if he hadn't been so preoccupied he might not be twisting himself up in anxiety over the fact that she's gone missing.

Natasha's a big girl. She can handle herself. Steve's seen her handle herself. He tells himself this all the way to Sokovia and it's the only thing that keeps his emotions in check as they form a battle plan to take back the city.

It's the only thing that keeps himself in check when he lets Banner take point in finding her.

He's never been so glad to see her than the moment she flipped past him on that flying rock, alive and fighting. Natasha's beautiful and deadly all at once, batons whirling, guns blazing. And she's outnumbered.

"Romanoff!"

Throwing her the shield is the most natural thing in the world and Steve knows it's not the time to think how right it looks on her arm as she protects herself from the bot.

When it's down, when they take it down together, they take a moment to breathe. The area's not clear, he knows that much, but nothing's attacking them at the moment. Rest when you can, gear up for the next fight. He looks at her and their eyes meet for the first time in what feels like days. "You okay?" Steve asks.

Natasha nods without speaking, glancing down and away from him, and he can't help himself: he puts his shield arm around her and pulls her in, hugging her tightly. "Don't scare me like that again," he mutters fiercely.

"Steve -"

"I know," he says. Her protest is soft, gentle. He's heard that tone enough times from other gals that he knows she's about to tell him she's not interested in him, she's with Banner. But there's a very good chance none of them are going to live to see tomorrow and he needs her to know this much before that. "I know. And it's okay. I just… I'm sorry I waited too long. I'm sorry about us. I'm sorry I hurt us by stepping away, trying to make way for you to be happy."

She relaxes just a bit in his tight grip. "I hated you for a while, you know."

"I know."

"I just…"

He kisses the side of her head, just briefly, the most he'll ever allow himself with her again if they all live through this. "You don't have to explain it to me. I just want you to be happy."

"If we live through this, I'll try my damndest," she says as he releases her.

Steve grins. "Language."

Natasha's lips twitch and then she's smiling at him - no, smirking at him, that Natasha-smirk, the one that he hasn't seen directed right at him in weeks, the one that says 'you're an idiot, but you're my idiot'. She punches him in the shoulder. "I missed you, Steve."

"I missed you too, Nat," he says, and there's a brief flash of a real, toothy smile.

They're moving the civilians inside when Stark says he's got an escape plan. Steve doesn't like it, hates the thought of sacrificing the few to save the many. He knows Natasha's going to argue with him, but he's been in this position before. These are civilians, this isn't their fight. They didn't ask for this.

He can't live with the guilt of sacrificing a few hundred people. Not even in the name of stopping a mass extinction of human life.

Natasha's ready to die for this, sacrificing herself and all of their lives to stop Ultron, and not for the first time his heart aches for her: Banner isn't the only one who hasn't had a good decade - a good life.

She deserves more. Better.

He's tempted to toss her onto a lifeboat and tell them to take off, but he knows she'll find some way back - first to kill him, then to finish the job. He finds out later - after Pietro's dead and Clint feels responsible - that Banner did just that. He carried her to the helicarrier before leaving Ultron to Wanda and going into hiding.

Because Banner loves Natasha, too.

She's hurting but there's enough going on in creating the new Avengers headquarters that she can lose herself in her work. He understands that, because he's busy too. Steve calls Sam in from the field, finally - it's been almost sixteen months now, and none of their leads on Bucky are going anywhere hot. Sam's not overwhelmed at the offer to replace Clint on the team, but his grin doesn't go away for at least a week. Rhodey's in too, an obvious replacement for Tony, and Steve hopes Natasha might find some common ground with Wanda.

The fact that most of their team has split up, retired or quit while they're still alive, doesn't phase Steve in the least, but he is surprised that Natasha doesn't leave too. She has every reason to. He mentions this one night as they're going over training plans for the new guys - and girl. She eyes him over her beer bottle. "Where else am I gonna go, Steve?"

His gaze flicks back down to his tablet and he makes some useless changes to the schematics. "You said it yourself, after we took down S.H.I.E.L.D., you wanted a new start. Said it might take a while."

"It did," Natasha says, overriding his tablet with hers and fixing his changes. "It didn't take. I don't belong out there, I never have. They took that option away from me," she bites out, sounding angry for the first time in weeks, and he knows who they are. "I figure it's the least I can do, making sure people like them can't ruin other little girls like me. So, this is who I am." She pauses for a moment, then looks up at him again. "That is, if you'll have me."

She sounds worried. Steve sits back in his chair, considering her words. There's a little furrow between her brows, and he's taken back more than a year, to a bedroom just outside of Washington, D.C. He leans forward, bracing his elbows on his knees. "If it were down to me to save your life, would you trust me to do it?" Steve asks.

Natasha's eyes widen as her words are parroted back to her. She holds out her beer, and he grabs his to clink the necks together. "Always," she tells him before taking a sip.

"You've always got a place with me, Nat," he says, meaning it. "No matter what happens."

Slowly, it becomes normal. Team strategy, going over reports together, late nights with takeout cartons and reviewing footage. The Vision becomes a normal sight around the new base, Clint's son is born and he officially retires. Tony backs out of the strategy meetings slowly, easing his share of the burden to Steve and Natasha. And Steve finds that Natasha's a much easier second to work with than Stark ever was. They have a rapport that he hasn't been able to duplicate since Dum-Dum or Bucky.

It's comforting. It's them.

For the first time in a long time, he feels like he belongs somewhere.

When Thor goes to investigate the Infinity Stone problem and Tony finally leaves, Steve finds Natasha in a brooding mood. He knows what she's thinking about and doesn't bring it up. If she wants to talk, she will. He knows that much. She slides into their banter easily though, slipping behind her work mask easily, and Steve thinks she'll be okay.

Just before entering the training facility, Natasha reaches over and squeezes his hand.

They'll be okay.