No one expects it to be Natasha who takes the death of this particular bystander so hard.

They've moved bodies before, from beneath crushed cars and the rubble of battle, but never one so innocent, so small...so young.

The child is a victim of what can only be described as an alien attack in central New York. They bring down half a building onto a school block that had already been evacuated by Steve - kids everywhere running, because lets face it, they'll follow Captain America anywhere he tells them to go, and Natasha's in the building checking for leftovers when the building collapses.

They run in to recover her but she's alive and perfectly unharmed. Steve finds her huddled in a corner. There's dust in her hair and her eyes are red but that's not from the thick air. She's whispering softly to a little girl who's lying in her arms, barely more than five years old - a kindergartener, they learn later. She'd been too afraid when everyone started running and Natasha had found her cowering under her teachers desk. Then the building came down at the wrong moment and the little girl was crushed. Natasha had bought her out of the rubble because she was afraid and now she was holding her, whispering that her mother was coming to find her and that she would be fine and that she didn't have to be scared, even though the blood surrounding them showed a different reality.

By the time Clint catches up to them and sees her on the ground with the girl's body in her arms, the little girl has stopped breathing and looks oddly peaceful despite the quick bruising, the blood and the dust that's settled everywhere by now. She's cradling the dead body of the child and she's not bothering to hide the thick tears that are rolling down her cheeks, leaving clean tracks in the blood on her face. Some of it's hers, most belongs to the girl.

Clint falls to the ground before her, tries to coax her arms from around the girl but she resists, telling him with a choked voice that she needs to wait until her mother arrives. Natasha says nothing more, and it shocks the other Avengers when Clint just sits on the ground before her and announces that they'll wait together.

It's an hour before the building is secured enough to bring the girls body out. Clint has shed his outer jacket which takes most of the blows in battle and wraps up the girl. Natasha insists on being the one to carry her out and there's chaos when a woman in the crowd who is already crying hysterically screams like her world has ended and takes her dead daughter from Natasha's arms.

Natasha stands lost after that, waiting for someone to direct her. Clint turns to her and puts his hands on her face. She snaps out of her daze and puts her hands on his wrists. They've shared some moments where the team have wondered whether there's something going on between them but this is by far the greatest display of something more than partnership.

"Tasha, look at me," he instructs firmly. When she meets his eyes she lets out a sob and puts her head on his shoulder. "It's okay. It's okay. You did what you could."

"She died..." she mumbled.

"There was nothing you could do," Clint told her. "You stayed with her, you held her...you made her feel safe..."

"But she died," she stressed. "I should have been faster-"

"Natasha," he says, but she cuts him off.

"She told me her name was Lilly, Clint..." she cried, with an expression on her face that made it look like she needed to claw off her own skin. "Her name...it's Lilly..."

And then Clint turns to meet the sight of the mother holding her too-still daughter and he's holding Natasha fifty times tighter than he was before.

"We're going home," he announces in a tight voice, and the pair say nothing more until they're returning to base.

Once they return to base there's a chaos because everyone watches them enter. Natasha is crying still and she never cries, and while Clint has tried to shake the dust from her hair it's still on her face and her field suit and she looks like she just crawled from under a mountain. Coulson greets them in the briefing room and tells them to stay put, that he'll bring her.

Natasha is directed to a chair by Clint who stands behind her with his hands on his shoulders and the others look between each other to silently question if any of them know who her is. They don't dare ask it out loud and sit in silence until Coulson returns less than a minute with a small infant in his arms who is babbling away as if the agent holding her has any idea what she's saying. He's murmuring back to her about Mamma and Daddy as if he understands completely, and the second they're in sight Natasha is on her feet. Clint pushes her back down because she's shaking so much and he takes the girl from Coulson, listening to the babble of 'dada...dada' that starts when she's in his arms.

Clint holds her tightly, kissing the girls head, and it was clear in his posture that he wanted to hold her until the world ended but instead he transferred her to Natasha's arms. Natasha held her so delicately in one arm and embraced her with the other, the girls head burrowing into Natasha's shoulder in a way that made it easy for them to hold each other the way they wanted to. She cried softly again and Clint stroked a hand down Natasha's hair while the girl babbled 'mamma' over and over.

Coulson approaches the other Avengers and nods towards the small family in the corner. "That's their Lilly. Lilly Romanoff-Barton," he explained, signalling that he'd heard the exchange outside the school over their communication links. "Fourteen months old next week."

There are no questions. It's clear that they've been together in more ways than the others have ever imagined, and the little girl is such a perfect mix of them - Clint's sandy hair and Natasha's peircing eyes, Clint's smile and Natasha's nose. She's undoubtedly a product of them both and from the situation before them, she's their entire world.

"Why did her name have to be Lilly?" Natasha cried as she held her daughter. "Of all the girls in the world..."

Clint leaned over and wrapped his arms around her shoulders, effectively embracing both of them. "Shh...it's okay."

"She died in my arms..."

"Not our Lilly," he told her. "She's right here. She's in your arms, she's perfectly safe."

"Mamamamam...." Lilly mumbled, and those were the last words into the room that the Avengers heard before they left to give them privacy.

"I can't keep doing this, Clint..." Natasha sighs when they're alone. "I can't...I just can't do this anymore."

"Then we go," Clint replies instantly. "I told you, this is your call. You wanna go, we've got a house waiting for us." He kisses the side of her head and waits for her reply. When there is none he holds her tightly. "I think it's time."

She just nods, and when they leave the room an hour later, Natasha's eyes aren't red anymore and their daughter is asleep on Clint's shoulder. Coulson is standing outside as if he's been there the entire time and Clint just nods. "It's time," he says to him simply.

Coulson nods and hands them a folder. Clint knows that it contains their original birth certificates, passports and the deeds to the house in Virginia they bought the day Lilly turned six months old. "Good luck, Mr. and Mrs. Barton," Coulson tells them, the first and only time he'll ever call them by their civilian names as he returns to them the wedding rings they give him for safe keeping each time they go into the field.

Another hour later they're leaving the S.H.I.E.L.D. base for the last time, looking so different to when they first set foot their. Their daughter is sleeping in a car seat and they have a bag each on their shoulders. What makes them look so different is that when they say goodbye to their team, they're smiling.

They look far more different when they gather in their back yard in Virginia ten months later for Lilly's second birthday, when Natasha is expecting their second child.