Tony
"What happened?" Tony and Steve ask in unison the second they arrive at the hospital. They are being led to Natasha's room by a nurse. Tony feels like he's walking through a fog.
On the way they pass Nick's room, where they see the right side of his face has been badly beaten up and he has a bandage over his eye. They see a policeman, taking a statement from another teenager with scrapes all down his arms and a large bruise on his head.
When they get to Natasha's room, both run inside. The doctor's not in there, so Steve frantically runs out past the startled nurse to find one. Tony's too focused on his girl to object, just wanting information.
Natasha looks so pale and weak, but she opens her eyes briefly, smiles, and says, "Daddy."
And then she passes out.
It's too much. Too much like another time when the person around whom his world revolved lay in a similar bed, looking weak and vulnerable and Tony can't fix it even though that's what he does- he fixes things. He can feel panic well up in him, taking deep, calming breaths and fighting it down with everything in him and demands someone tells him what was happening to his daughter.
The doctor arrives and pulls Tony outside to talk. Tony gestures to Steve and insists he's allowed all information as well. She nods and they follow her to her office, where she tells them that Nick was driving Natasha's car, which got hit by an oncoming truck. Nick had acted quickly, trying to swerve the car to take the brunt of the impact, causing massive damage to his left side. Both kids were immediately knocked unconscious. They were pulled out of the wreckage and away from the intersection before being rushed to the hospital. Unfortunately, the force of the impact still managed to cause severe damage to Natasha's kidneys.
Tony feels his world shrinking, his heartrate picking up, and then he feels a hand on his shoulder. Steve is still staring straight ahead, listening to the doctor speak, but keeps a steadying hand in place, grounding Tony.
The doctor looks at both of them in pity and tells them Natasha will need a kidney transplant. She has been added to the donor list, but she would need to stay in hospital. And though she keeps going in and out of consciousness, she should remain stable for a few days.
Tony starts to turn to look at Steve, but before he can, Steve blurts out, "Take mine."
The doctor glances between them, and something must register, because she simply nods and tells him she'll have the tests prepared.
Tony and Steve have a silent conversation, realising that after all this time, they'll have to finally tell Natasha the truth about "Uncle Steve." They seem to come to an agreement, and Tony nods and exhales loudly before saying, "Okay."
Steve goes into Natasha's room first, carefully brushing her hair from her face and smiling sadly at her. He leans down and busses a kiss across her forehead, stroking her cheek with his thumb.
"Love you, Nat," he promises. "You're going to be okay."
The nurse comes in to take Steve for testing, and Tony takes his spot in the chair next to Natasha's bed. He grabs her hand and closes his eyes, willing her to get better again.
She wakes up, disoriented for a moment, then finds his face and smiles.
He gives her a weepy smile back.
"Hey Little Buddy. How you feeling?" he asks.
She shifts a bit, then grimaces.
"Like chopped liver," she grunts out, trying to smile at her own joke. Tony manages to huff out a laugh for the effort. "I'm sorry, Daddy. You were right, I shouldn't have-"
"Hey, no. Don't be sorry. You're not allowed to be sorry. Not now." He kisses her hand, then smoothes her hair back some more, looking at her bruised face. "Nat, Kid. Listen. We've got to talk… and it's not going to be easy."
She looks at him critically, her mother's eyes and hair and expressions and he feels like he's about to betray Pepper's confidence by what he has to say.
"Something's wrong," Natasha whispers, reading it off him.
"Yeah. It is. You need a new kidney, Sweetie. It- it's pretty serious."
She looks away from him, processing this new information. Tony takes a deep breath and gives her hand a light squeeze.
"Uncle Steve has gone for testing."
She looks up at him sharply, a furrow in her brow.
"But-"
Tony shakes his head, ploughing on.
"Kiddo…Something happened. Before you were born. Your mom… well, she was amazing. The most wonderful person I've ever met. But, she wasn't perfect-"
"Dad-" Natasha reaches weakly for his face, trying to stop him from talking. He pulls back, clutching her hand tighter.
"No, I should have told you this years ago. I just thought, hoped really, it didn't matter-"
Natasha finally does reach up, guiding his face so their eyes meet.
"Daddy, listen! I know about Mom and Uncle Steve. I know how I was made- how I was born."
Tony's breath catches in his chest, and it takes a long while before he's able to exhale fully.
"How?" is all he's able to get out when his brain reconnects.
Natasha shrugs lightly, then hisses when the movement jars her.
"Happy told me when I was 10. Well, Bruce started to after having a few too many, but then Happy thought it would be better if I got the whole story."
Tony is still gobsmacked, and frustrated at his friend.
"I swear that man acts like sweet, mild-manner scientist, but get a few drinks in him and he's an uncontrollable monster." He shakes his head, then refocuses on Natasha. "I'm sorry, Sweetie. I just thought-"
She stops him, giving a groan as she moves to get comfortable even though he can see it pains her.
"I know. I love you, Dad. I always have. And I love the life you chose for me, all of it- with you and Uncle Steve and our family. I wouldn't change it." She gives him a small smile as her energy starts to fade. "Thanks for loving me, even when you weren't sure."
"I was always sure," Tony swears seriously. "From the second I found out about you; you listen to me, Natasha Stark. You are mine. Unconditionally, irrevocably. This- it doesn't have to change anything if you don't want it to."
She shakes her head slightly, fighting to stay awake.
"Want to stay with you, Dad. Always," she mumbles.
He ignores the wetness in his eyes as he pulls up their clasped hands, kissing hers, before setting it down on the bed.
"Get some sleep, Kiddo."
She's out before he finishes his sentence.
He stands when there is a knock on the door, walking out and closing it behind him so no one would wake Natasha.
Steve is standing there, a frantic, confused, desperate look on his face, and he refuses to meet Tony's eyes as his own rapidly shift back and forth. He shakes his head and steps back when Tony reaches for him, still not looking him in the eye.
"Tony, the doctor… has some news. I… I gotta go," he sputters, turning and walking out quickly, both hands in his pockets and his head down, a familiar move Tony knows means he is trying to make himself smaller somehow. A sudden fear grips Tony as he faces the doctor alone. Was something wrong with Steve's kidneys, too?
The doctor is staring at Tony curiously, ignoring the man walking away.
"Mr. Stark, Mr. Rogers tells me he's Natasha's biological father."
Tony swallows, his mouth suddenly dry as he faces a fact he's spent 17 years happy to deny.
"That's right. My," he takes a deep breath, "my wife was her mother."
The doctor looks at him in pity.
"But Mr. Stark, Natasha is AB-"
Tony stares back, confused, before nodding.
"So was Pepper."
"Mr. Rogers is O+." The doctor points toward where Steve has just rushed off. "Mr. Stark, that makes it virtually impossible for him to be biologically related to Natasha in any way."
The world seems to stand still, and Tony's heart beats loudly in his ears.
"But, then-" he begins, unable to finish his sentence.
"Mr. Stark, what is your blood type?" The doctor prompts him.
He looks up, disbelief coursing through his body until he says the words aloud, not fully processing them at first.
"So… she's mine? She was always mine? She… she's my kid? She's mine?"