She is the one still point he can revolve around, that he can come back to and run up against that keeps him from flying apart, the object that affects gravitational pull so that he centers around her instead of falling away.
He is her quiet place, the mind she can fall into that's as familiar as her own, but not herself, that she can dive into like cotton wool and muffle the voices and feelings that press and push and howl around her all the time now, like a harsh red wind.
She will sit, still as a statue, reading or writing while he ranges around her, darting back and forth for a look or a touch, so that she reminds him what stillness, and what steady means. It reminds him who he is and where he is before he gets too far away to come back to her.
He'll sing in his head, nonsense songs, numbers, words, rattle off poetry they learned in school or the times tables or even dai's recipes he remembers from before, a comforting babbling like water over stones that washes over her and washes all those other thoughts away - they've always done this for one another but now it's just more.
When they were six, she would stand at the end of the stream, holding onto his shirt and leaning backwards so that he could reach for his sailboat and not fall in. When they were eight, she would angle herself between him and the wall, so that the other children had to speak past or around him to get to her.
He has always been her quiet place, but never because he was quiet. When he goes silent in her head, and all she can hear is what she dimly realizes is her own screaming, she knows something awful, something wrong. It sounds like the train screeching against the tracks, and she reaches like she did then, reaches, grabs, and holds. She has always been his still point, but now she holds him still and frozen. She brakes the flow of blood, the very degradation of cells... she can't repair, can't undo what's been done, but she can hold.
Still, she feels him slipping farther away from her as she rips out Ultron's cold heart.
She expects to die there, is only holding on as long as she can so that they'll remain together and because she cannot let him go.
She doesn't die.
There are arms around her, supporting her, and they are not her brother's, but it's not as jarring as she might've expected it to be (if she'd been enough in her right mind to expect anything at all). Ultron's Vision shields her from his own thoughts, but she thinks he maybe can't shield himself from hers, and she watches distantly as he follows the path of her energy down their red tendrils snaking invisible from her mind to Pietro's heart.
It gets easier to hold onto Pietro.
It gets easier to drift in that place between, that still and quiet place between the two of them, the place that was her first point of awareness, which crystallized in the dust and damp under a broken bed, and which is where she wants to be in her last moment, and she doesn't even notice when she's laid down on her side on the floor of the transport next to Pietro's body.
Clint's first inkling something's going on is the shift, the brush of fabric even as he's lying on the bench with blood drying between the graze on his side and the hand he's pressed there, where he's mostly managed to stem the bleeding. He cracks one eye open and flinches because he's still looking up, and the sun is there being it's usual too-bright bitchy self, but he turns his head and sees the red guy standing over the boy, and then sees the girl's body next to him.
He thinks no, he thinks damn it, he thinks maybe it's better that way because he'd worried about her when Pietro fell.
He looks up at the strange android eyes that see too much for his comfort and they're so abstractly quizzical it pisses him off. Clint opens his mouth to tell the guy to leave them be, to quit staring at them like some kind of sideshow attraction and thinks about aliens and gods and bread and circuses-
But the Vision beats him to the punch.
"They are not dead," he says softly. "She's holding him here. I think... as long as she lives, she will not let him die, but she cannot fix him."
She cannot fix him. It echoes in Clint's exhausted brain, and his side burns.
There's someone who can.
Clint's fingers dig into his vest, between fabric to press harshly against his skin - skin that doesn't feel the same but rips and bleeds like the real thing. "Shit," he mutters, pushing himself up, and the blood starts flowing again as he tears open the barely formed scab but so what, won't be the first time, Nat and Laura can yell at him later but... "Dr. Cho - the cradle that made you," he tries. Pain is a bitch and is stealing his voice out from under him.
"It was damaged," the Vision starts, but gets a far away look in his eyes.
"You know how to fix it? Can you do something like that? How long do you think she can last?"
"With intervention, perhaps long enough," the Vision says softly, and then he's up, away, and the transport has already touched down on the carrier and Clint's barking orders at the med techs and despite their incredulous looks he makes them put both bodies on stretchers, orders them not to separate them and do whatever they have to do to keep the girl alive. One starts to protest and he throws every ounce of intimidation he's ever learned from Natasha into his expression and they fall silent.
It's a Hail Mary pass, maybe the Hail Mary pass, but damn if he's not gonna make the attempt. He owes the kid, anyway, and the rest? They can sort that out in the aftermath.