Officially, SHIELD is not looking for the Hulk. Natasha is, when she has the time, but that is strictly off the record. When Steve gives her a far too knowing look, she shrugs. He's still chasing ghosts of his own.
"Everybody needs a hobby."
There are hints here and there- a doctor in rural Indonesia who turns out to be an actual physician on sabbatical, rumours of a monster in Cambodia that is actually an exceptionally large sun bear. Her first real lead is an actual postcard six months after Ultron's defeat.
Having a lovely time in Fiji. Snorkeling is amazing this time of year.
She knows he won't be there.
She flies out anyway.
The postcard is traced to a small community on Beqa Island. She doesn't find him, but she does find a Hydra base that produces important information and she understands why he sent it now.
"There's something you need to see, Nat," says Steve.
Sam has turned up some video surveillance in the search for Bucky. It's Bruce, head down and walking briskly, but even with grainy footage she has no doubt it's him.
"Nearly a week, and those are the docks. He's long gone."
"It's something," she says, even though she knows Steve is right.
She calls Fury from the jet, gives him some vague excuse that he has the decency to pretend is believable. She misses the resources that SHIELD used to have, but even then people were their greatest asset and she was the best.
She spends three days asking questions. She is hot and tired, but she's also good at her job. There are some answers- a man in a market remembers selling the hat he's wearing in the video but not the person who bought it, she identifies the room he rented by a doodle on a piece of paper. But it's mostly just no- no, I don't remember him. No, I never saw him. No, no, no man like that ever came here.
She marvels at his ability to become completely forgettable.
Three days after Steve dies, she gets a phone call.
"I heard. Maybe I should come back."
He won't. They both know it. But it's nice to pretend for just a moment as the silence hangs between them.
"No," she finally says. "Not until registration is officially off the table, at least."
"Sure," he says, as if it was ever an option.
She doesn't know what else to say, so she ends up telling him everything. How stupid it was. How none of it should have happened. She's not sad, she's angry. And by the time she's done, Bruce is angry too. She can feel it simmering in the silence coming down the phone line, and she supposes that it's their way to mourn.
"He was a good man."
Not all experiments create monsters.
It's only after they hang up that she thinks to trace the call. It's too late, but when she hears about 20 acres of South American rainforest uprooted overnight she has a pretty good idea where he had been.
She laughs for the first time in weeks when she sees the photos- not only had he uprooted trees already set for destruction, but he had carefully stacked them for easy disposal.
"Aunt Nat, can you please, please, please come see me? I've been practicing every day and I know I'll get my belt if you're here."
She's busy, but Natasha goes anyway. No point in saving the world if you don't live in it from time to time.
They are sitting on the front porch the next morning, drinking coffee and watching the kids playing in the yard. Nathaniel is toddling after his siblings now.
"Dr. Banner was here last week," says Laura, not looking away from the kids.
It's the first time anybody has been in contact with him.
"How was he?"
"You're slipping, Agent Romanov. The man before the mission?"
She's teasing, but Natasha hates herself for the weakness.
"He seemed... tired, but optimistic. He asked about you."
"What did he want?"
"To apologise for the massive inconvenience of his presence, check on you even though he pretended he wasn't, and ask a favour. In that order."
Sounds like him.
"What's the favour?"
Laura looks at her.
"He needs some... supplies he can't get himself, and thinks you might be able to get them. I didn't ask questions, just tucked the envelope away and found a reason for you to visit."
"The Bartons are all impossible," says Natasha, but she smiles and takes the envelope home with her.
It takes her nearly a week to open it; it's his writing, and she manages to get what he needs quickly. It requires going through official channels, but it does allow her to confer with one of the scientists on staff. Simmons says it looks like it's probably something to do with gamma radiation but won't venture a further guess. The only hint is the sign off: I hope I can safely explain this to you soon.
When she drops off the equipment, she includes a note.
There's only one tracker. Little box. Be safe, I'll see you soon.
She doesn't hear from him. She tries not to mind.
It's 3 am and it takes her a minute to realise who is on the phone. It's been nearly a year since the last time. He sounds exhausted.
"Sorry, time difference. Wakanda. Go. It's important."
"That's... helpful. Anything else?" She's out of bed and getting dressed.
"The research was a dead end, but thank you."
She suspected as much, but it's a surprisingly hard blow. There's no time to dwell- she has the team on the jet within an hour.
They leave Wakanda with another gem and a potential new ally, but no sign of Banner. She's getting used to it.
He's standing in front of her, sheepish.
"I think... I think whatever's coming is something not even The Other Guy can outrun."
"Probably not," she says. "But he'd put up a good effort."
She means it to be a light-hearted comment, one to mean 'I forgive you' and 'welcome back', but her voice is a little too sharp and terse when she actually says it. He notices, of course, and shoulders the blame.
"I'm sorry. I had to go, but I think I might have hurt..." he shakes his head, changes what he was planning to say. "I think I hurt people in the process and it wasn't my intention."
She shrugs, gives him an apologetic smile of her own.
"We all have things we need to do, even if we don't like it."
It's the closest she'll come to admitting her own guilt in how things turned out.
"Come meet the rest of the team," she says. "Then I'll fill you in."
She takes him around the facility. Tony had been designing it before the incident with Ultron and isn't completely unfamiliar, but he follows her quietly, thinking.
"Did he really end up dedicating an entire room to his ego?"
"I had to convince him that a life-sized portrait of Tony Stark in every room was too much. Thank God for Pepper."
His laugh is just a gentle snort, but she finds it familiar and comforting. She watches him carefully as she leads him around, stopping to talk to old friends and new allies. He's still the Bruce she remembers; quiet and diffident, observing everything. Self-deprecating and dryly humourous with people he's comfortable with. Brilliant. He spends forty five minutes talking to Selvig and Foster about something that goes completely over Natasha's head, although she files away enough to bluff her way through a conversation. At one point Foster looks up, the only one to notice that she's still there. Bruce follows her gaze.
"My handler," he says by way of explanation. "Making sure I'm not, uh, not compromised. Given my unexpected return and all."
"Huh," says Jane, then continues on her original thought.
When Bruce finally excuses himself, promising to read some relevant papers that had been published during his absence and get back to them, he looks to Natasha.
"I can show you your room," she offers. "Tony had most of your stuff moved here."
"Tony is an optimist."
She says nothing, just walks quickly towards the sleeping quarters. When they get to his room, she shuts the door with enough force to make him jump.
"I'm not your handler, and I knew you would come back," she tells him. She knows the advantages of saying so- fostering a bond of trust and camaraderie, checking for signs of deception- but really she just needs him to know. "You never run when it really matters."
His laughter is harsh. "I always run."
She kisses him as a reply; it's been so long since she's done it without an ulterior motive that she stumbles for just a second. And he's looking at her with such gentle amusement that she has to regain some equilibrium.
"I thought it best to do it now, before the world ended and I missed my chance. Call it curiousity."
He nods, but it's the sad, withdrawn nod that he tries to cover up with humour.
"You know what they say. Curiousity killed the Nat."
She groans. "Some days, Banner, I don't know why I missed you."
The look of surprise on his face stings more than she cares to admit. .
When it's time to suit up a week later, she finds him waiting in the jet. She sits beside him, listening to his steady breathing.
"I think I've done enough. Or maybe it's not enough, because it can never be enough," she admits.
His hand meets hers, solid and cool and present.
"If we live through this, I have to do something different. Find a different way to clear my debts. Be something else."
A barely perceptible tightening of his hand.
"I hear Greece is lovely this time of year," he finally says.
"Greece..." she repeats, letting the idea roll off her tongue. "Yes, Greece sounds perfect. A nice villa somewhere near the sea. You'll come, won't you?"
She's pretty sure she's more scared of his answer than she is of Thanos. The alien only has the power of the universe at his disposal, after all.
"It's a bad idea," he says.
"Not my worst."
"No, it's not your worst," and he smiles. "I can try different."