A/N: And here's the last one. Prompt from maidenpools: The two of them meeting up post-Battle of New York? We know they all parted ways so it would be interesting to see how they'd interact after meeting up again.

I really, really loved this one, since I got to indulge in some of my favorite headcanons. Warning: there is some blood in this.

Three days after Natasha drags herself out of a collapsed Hydra base, she winds up slumped in the elevator of Avengers Tower.

Jarvis had agreed to her wish of not notifying anyone in the tower of her arrival. The first time it happened, Stark sent her a text saying that her floor was the 64th. He knows enough about her to leave her alone, especially because she only comes by to crash for a few days. She never stays long, and she always leaves again - usually for months at a time.

The elevator doors slide open, and she almost stumbles out, too exhausted to glance at the floor number display on her right, but she and the person waiting on the other side of the doors freeze up when they realize the other is there.

Dr. Banner looks about as dead as she feels. There are bags under his eyes, and he has a rumpled look that she doesn't find unattractive. They stare at each other dumbly for a few moments before she grunts and moves back, effectively hiding all traces of tiredness and/or injuries she has.

"Agent Romanoff," he greets. "It's been a while."

A while… right. More than two years probably is a while. Natasha moves aside so that he can enter the elevator, nodding in response to his greeting. She never normally runs into anyone else on her occasional stops at the tower. Partially because she's still trying to sort her shit out, and partially because she knew they would try to convince her to stay.

There's a terse silence between the two of them until the elevator stops at her floor, at which point she walks out. She doesn't let herself sag until the doors close behind her.

She must not have even made it to the bed last night, because she wakes up with her face in a couch cushion.

Not the wisest decision on her part - the muscles that were aching last night are worse now, and the knife wound on her arm is throbbing. Unable to stifle a groan, she rolls gingerly onto her side, trying to sit up. She peels off her jacket as she does so in order to inspect her haphazard bandaging of her arm. The wound has begun to heal, but it will still take time. Considering she's feeling more skittish than usual, she has a feeling that it's time she doesn't want.

There's a sharp intake of breath from behind her, and she whirls, cursing herself for not noticing.

Dr. Banner is standing in the doorway of her kitchenette, holding a bowl of what looks like oatmeal in his hands, but he's looking at her bloodstained bandage.

"Don't get ahead of yourself," she rasps, wincing at how raw her throat is. "I know you're not that kind of doctor."

He ducks his head, but makes his way over to her and hands her the bowl. "You should still get that looked at," he tells her. He looks embarrassed, eyes darting to the doorway.

Natasha sighs. "Sit down, Dr. Banner," she orders.

He does so, looking anywhere but her while she starts spooning oatmeal into her mouth. "JARVIS informed me that you might be in need of medical attention, so he let me in this morning. I thought food might be better to start with."

"Traitor," Natasha says to the ceiling.

"I am programmed to make decisions that result in the optimal health of the tower's residents," JARVIS replies. "Mr. Stark has added you to the list since your third stay, Agent Romanoff."

Of course he did. Stark has always been more observant than he makes himself out to be.

Bruce looks at her. "How many times have you dropped by?"

"Five," Natasha says. "This is the sixth."

"Never wanted to say hello?"

She shrugs. "I didn't plan on staying long."

Bruce sighs. She looks over at him, before attempting to eat more oatmeal and realizing that she's finished it. She sets the bowl down on the coffee table, fighting off a grimace when her arm twinges.

"Thanks for breakfast," she says. Her voice is still shot to hell. "And I guess you can look at the arm, if you want."

He raises an eyebrow at the dental floss stitches she used to fix it up, thought whether it's at the material used or the precision at which she'd sewn her wound up is a mystery to her. He cleans it up and puts antiseptic on it for her before re-bandaging it more carefully. She tries not to doze off during the process, but the exhaustion is getting to her again.

Bruce notices. He doesn't say anything, but he gets her a glass of water before helping her to her bedroom ('helping' means walking with her and staying close in case she collapses). He's a very unobtrusive medic, and Natasha realizes that she doesn't really mind his presence.

"I can come back later, and cook dinner," he offers.

She shrugs. "Maybe."

He does come back later, but she's already gone.

The next time she returns to Stark Tower, she actually does collapse in the elevator.

This is less because of aches and exhaustion, however, and more because she was hit by some sort of drug that's been blacking her out for the past few hours. When she comes to, she's still in the elevator; it's waiting at her floor. Bruce is sitting cross-legged next to her.

"Hey," he greets. His voice is distorted in the enclosed space. "JARVIS said you'd wake up on your own. I didn't think it was a good idea to move you until you did."

Natasha nods, then stands a little unsteadily. She manages to walk with some dignity to the bathroom, where she promptly vomits into the toilet.

She hears Bruce speaking to JARVIS behind her. He's giving her space. She thanks whatever deity might be out there that she cut her hair short recently. She starts feeling shivers crawl up her spine when she finishes vomiting, but she stands up again and rinses out her mouth without incident.

Bruce is kind enough to heat up some broth for her. She's not really sure why he's doing this, but she decides not to complain. S.H.I.E.L.D. certainly wouldn't have given her this kind of consideration after returning from missions (oh, that's opening up a can of worms she does not want to confront right now).

"I'm tired," she murmurs, once she's finished the broth. She does not say, I'm tired of all of this, but I don't know how to stop.

Bruce gets it, she realizes. More than anyone else, he gets it.

Natasha's been a lot of things over the years, but understood has never been one of them.

(This time, leaving is just a little bit harder.)

The third time, he's the one who finds her.

She's in Montreal, bleeding out in a seedy motel. There's a knock on her door; she silently curses in Russian before grabbing the glock that sits on her bedside table and moving silently to the door, ignoring the pain in her thigh. There's no peephole, so she holds her breath for a moment before ripping the door open, ducking behind it. She almost bashes it into what she imagines is an adversary when a voice says, "Natasha?"

She stops. Sticks her head out from behind the door.

"Hey, Bruce," she greets, giving him a smile that's a little too feral. He pales at the sight of her, though whether it's from concern or fear, she isn't sure. She isn't certain if she cares - she knows that she looks like some kind of demon. Blood probably still on her teeth from how hard she'd bitten that one guy, blood lazily oozing from her thigh, thanks to a surprisingly competent sniper that Hydra had employed. She's aware that there are bruises on her face, too.

"Jesus," he breathes. "Are you -?"

"How'd you find me?" she asks. She doesn't have enough energy to sound accusatory.

"Clint," is all he says. That bastard.

He moves further into the room, taking in the sights - the bullet she'd dug out of her thigh lying on the sink edge, the clothes thrown haphazardly on the floor. It's only then that he seems to notice that she's in her underwear, and coughs politely, looking away. She laughs a bit at that.

"Come on," he says, nodding at her thigh wound. "Sit on the bathtub edge, I'll stitch that up."

Natasha's getting delirious from blood loss, but she's smart enough to know that it's wiser to comply. He had the foresight to bring a first-aid kit along, so he has proper stitches this time. She paws around under the bed for the bottle of vodka she stashed underneath when she first arrived, opening it easily and taking a swig while she sits.

He nods at the bottle while he's getting his supplies out. "I'm guessing that's how you got through your other stitch job?"

Natasha smirks by way of reply. "Helps with the pain, a bit," she admits, taking another swig.

He gives her an unnerving stare. "Even with it, it must've been excruciating."

She stares back. Doesn't give anything away.

It's a bit less painful than last time, but it still hurts, and it takes all of her concentration not to tense up when he carefully inserts the needle under her skin. When he's finished, he wraps it the same way he wrapped her arm. His hands are warm.

She catches his wrist when he makes to pull away, holding it firmly until he meets her eyes. "Thank you," she tells him.

"You're welcome," he replies.

He cleans up some of the blood while she changes into sweats and a t-shirt. She rinses the blood from her mouth, until there's no trace of it left, but looking in the mirror - that demon is still all she sees.

He goes out for a bit, leaving her on the bed with the TV on (she suspects that he doesn't want to leave her alone with her thoughts right now). She doesn't really absorb anything that happens on it. He comes back with takeout, and watches without hiding his concern as she eats slowly, forcing the food down.

"You know," he begins, "for a secret agent who's supposed to be avoiding trouble, this is a hell of a way to go about it."

She quirks one side of her mouth up. "Avoiding trouble isn't the secret."

Bruce decides to break off their bad parody of their first meeting by saying, "If there's one thing I've learned, it's that you can't run forever, Agent Romanoff."

"I'm not an agent anymore."

"Okay." He shrugs. "Natasha. On behalf of Tony Stark and Steve Rogers, we'd like to offer you the opportunity to officially rejoin the Avengers."

She laughs. "We never really officially joined in the first place, did we?"

He smiles. "Guess not. What do you think?"

"That we'll probably all kill each other." Natasha can think of a million ways to deflect, to escape out of Montreal the way she always does, and go back to life the way it's been since S.H.I.E.L.D. fell. Avoiding American soil, avoiding getting killed by old (and new) enemies. Keeping in contact with a couple of people, but not really connected to anyone.

It could be any number of those reasons, why Natasha finally says yes. But really, she's just tired. So god damn tired.

Then she looks at Bruce when she voices her acceptance, and she sees genuine pleasure on his face, and admits to herself that yes, he might've had something to do with it too.