"Dad, you wanna go down with me? Give blood now?" Alexis eyes were on her father.

Kate sucked in a breath, dived in to rescue him. "Are you balking, Castle? Alexis, looks like I better go with him, hold his hand when he gets scared."

Alexis jerked her head back to look at Kate, a flicker of hope across her face, because of the teasing. The flirting.

Damn. Not her intention.

"Detective Beckett better go with me," Castle said, his voice smooth. The cover-up undetectable.

How long had he been doing this?

"I've got a couple more things I have to do, and then we'll be down, Alexis." Kate smiled at the girl, helped her clean the trash off the table from their lunch. Her heart was pounding.

When Alexis hugged her father good-bye and went back down to the Blood Mobile, Kate sank against the conference room table beside his chair, stared at the door, at the negative space where Alexis had left.

She swallowed hard.

Castle leaned back in his chair, put his hand on her thigh, his thumb stroking absently. "Fast thinking."

She looked down at him, hands planted on either side of her for balance, watched the careful way he wrapped up all feeling behind his eyes. Until it was gone. She'd seen that before.

She had questions. She was a detective. Poking her nose where it didn't belong was second nature, but right now, this moment, she couldn't do it.

She nodded. The room was silent. His palm on her thigh was warm, heavy. It seemed an afterthought.

"I won't tell her, Castle. Anyone. Ever."

He removed his hand, stood up, his chair clattering back. He shrugged his shoulders back into his jacket and stood with his hands limp, his eyes on the door as well. She thought he looked. . .defeated.

"Thank you."

He opened the door and walked out.

In the open atrium on the ground floor of the 12th precinct, Kate stood off to one side, behind a pillar, and waited for Alexis to sit down with the woman next in line. With the girl now occupied with administrative duties, Kate gestured for Castle to follow her.

They weaved their way through the crowded foyer, Castle's hand somehow in hers, so we won't get separated, heading towards the Blood Mobile. Castle had a donor card, so he was hoping to skip the registration line where his daughter was volunteering.

Kate rapped against the door of the trailer and walked in, apologizing with a look to the off-duty uniform who'd been next in line. A nurse met them at the front and gave her a puzzled look.

"Ms. - er - Detective Beckett?"

"Yes. You're Alisha, right? Ms. Masters? We spoke on the phone, and then I came and picked up that roll of stickers for Alexis Castle."

"Yes, yes, right." The nurse smiled back and waved her forward. "And who's this?"

Castle crowded in close behind her, and Kate turned, gesturing to him. "This is Alexis's father. Richard Castle."

"Oh! Oh my word. The novelist. I didn't make the connection."

Castle grinned, his playboy grin, and turned on the charm. Only Kate could see how thin it was, how it had worn out in some places.

"That's me. Your surprise means I don't look old enough to have a teenaged daughter. Right?"

"Oh, oh, well no." Alisha didn't flush; Kate gave her that. But she did back up a step and put a hand to her chest. "We're just - this is really - I mean, I love your books. And oh, Kate Beckett!"

Kate, startled, rejoined the conversation. "Yes?"

"You're Nikki Heat!"

She felt Castle shift beside her, his hand brush hers, pinky fingers hooking. "She's not Nikki. But she is my muse. I get to tag along with her and the other members of her team."

Alisha had already put the rest of the puzzle pieces together; Kate could tell by the sudden dimming of her eyes, the shadow that ghosted over her. She knew Kate had been shot, figured out what Alexis was doing with the blood drive.

Kate was surprised that it didn't bother her; she was. . .proud that Alexis wanted to do this, had organized this whole thing in response to tragedy. Proud that Alexis cared.

Castle lifted an arm and rolled up his sleeve. "Well, I guess it's my turn. Kate's here for moral support."

Kate.

Beckett, she thought, but couldn't correct him. In front of these people. She could see two more nurses bleeding patients dry, sorry, donating blood, and she followed Castle back to an empty chair.

Alisha handed him over to the nurse there, introducing him only as Alexis's father.

Alexis's father.

Kate was struck by how incongruous it sounded now, out of a stranger's lips. Not wrong, not at all, just. . .peculiar. Like a funny taste in her mouth. Like knowing the ending to a film as she watched it for the first time in the theatre, guessing the outcome, and being certain that's how it had to be: oh, he *is* one of the dead people.

The nurse took down his information from the donor card and his profile came right up on her computer screen. "Oh, good. Universal donor."

Kate held her breath, but the woman said nothing about Alexis, about anything, and even though the moment was already over and past, so quickly, she still reached out and took Castle's free hand, surprised at the intensity of her need. Comfort. Relief. Shock.

He squeezed back, as if he knew exactly.

The fat yellow band was tied around his upper arm; he was given a neon pink stress ball to squeeze in his right hand. Kate kept ahold of his left and sat in the chair beside his station, trying not to think.

She averted her gaze when the nurse put the needle in, felt Castle squeeze her hand.

"You're not. . .squeamish." He chuckled at her and squeezed her hand again. "Kate. Dead bodies. Every week. Gruesome, dead bodies. Bloated. Stabbed. Flies. That smell."

"Thanks," she breathed and met his eyes. Then realized he wasn't trying to help distract her, he was pointing out the irony. "Oh. Yes. Well. They're dead. And you're alive. And that was a needle."

He lifted an eyebrow and Kate's eyes went involuntarily to the dark red line filling the tube, curling, down to the first pack. A strange flutter set up in her chest.

"Are you next, honey?" The large woman in the next chair over gave Kate a grin. "It's no problem. Easy. Promise."

Kate shook her head. "Just here as moral support."

The judgment that drew across the donor's face didn't phase Kate a bit. She couldn't care less what this woman thought of her, wearing her holster and shield and not giving blood. She had already turned back to Castle, but he was sitting up to look at the woman, defending Kate's honor.

So to speak.

"She can't give blood. She got shot. She's the reason we're doing this."

Her chest squeezed tighter; Kate, in retaliation, squeezed Castle's hand just as tight. Shut up. The nurse was trying to get him to lay back, and he did, blinking at her.

The nurse handed him a sprite and told him to take small sips. Then she headed to the front of the Blood Mobile, leaving them mostly alone.

"Castle," she chided.

"Ridiculous," he muttered, apparently still offended for her.

Just the same. Same man as yesterday, as the week before. Same man as two hours ago, before lunch, when she knew less and more all at once.

Alexis's father.

"How long?" she asked suddenly, and her hand clenched against his, without her say.

Castle turned his eyes to hers, the can of Sprite between his knees, unopened, and rhythmically squeezed the neon pink ball. Not saying anything.

Kate let go of his hand and reached for the Sprite, popped it open. The nurse had left a straw on the little table drawn up to his chair. She slit the paper open at the top, started to tug on it, but changed her mind.

Let her instinct take over. Her baser nature. Her. . .the Castle side of her.

She lifted the straw to her lips and blew the paper into his face.

He laughed out loud, flinching even as he laughed, and crushed the straw paper to his chest, staring at her.

Kate smirked and stuck the straw in his sprite, handed over the can. He squeezed the neon ball and took a sip, the faint edges of his smile still clinging to his lips.

"All her life," he said finally, sipped again.

All her life.

Kate closed her eyes, took a breath, opened them again. He was watching her, studying her for signs of stress, like an engineer might study a theoretical model of his design. Looking for weakness. Would she hold up?

Yes.

"At birth?"

Castle shrugged. "Knew for sure then."

Had doubts before that. Her throat closed up. Amazing man. Just.

She put her hand over her mouth and propped her elbow against his chair, watching him back. Studying *him* for signs of stress, cracks in his foundation. She found none.

"Wow."

He quirked his lips at her, glanced to his right as the other woman was allowed to rise from the chair. Her assigned nurse followed her to the back where Kate could see a table with cookies, crackers, more sprite. The woman sat there while the nurse took her pulse, making sure the woman, post-donation, wouldn't faint.

Castle put the sprite back between his knees and took her hand again. His was clammy from the condensation, but strong, and that was its own warmth.

"Kate."

She drew her eyes back up to his face. She already knew what he was going to say. "Doesn't change anything."

He sighed, relief and acknowledgement. "Doesn't change anything."

There was a story here, a story she wasn't privy to, might never be allowed to hear. And that hurt; she wanted his secrets, wanted him bared to her, wanted all of him.

More.

"You have full custody," she said slowly.

He didn't confirm or deny, but she already knew it. No paternity test then. And Meredith either never contested this qualification of their divorce, or she had too much denial to even think about bringing it up as a point of contention.

Damn. The things this man had gone through, to keep this little girl.

His little girl.

Yes. His daughter. "I - I can't imagine," she said finally, meeting his eyes again.

He was smiling that soft, eyes-crinkled smile. "There's nothing to imagine, Kate."

Amazing man. She'd thought it before, now again. Still, to take this small thing that needed a parent, needed love and attention and time and sacrifice, and to make it your own, to love it, the little cuckoo, to father the fledgling-

Doesn't change anything, he'd said. She'd said it first. Because she knew him, knew Richard Castle, and the lengths he went to.

She ached with it. With the story not told, the ending not written, the story rewritten into a happy ending for one girl who would never know.

Never needed to know.

Kate wanted to ask If not you, then who? and she wanted to know his dark-of-the-night second-guessings; she wanted to find Meredith and look her in the eye with that knowledge; she wanted to stroke the side of his face and promise it would never happen again, that she would never do that-

Oh.

oh.

Her hand tingled against her thigh, the blood warm in anticipation. He still had his sprite-cold fingers wrapped around her other hand, and his eyes were closed as he squeezed the neon stress ball.

Her mouth was dry, her whole body jangling with nerves. The nurse would come back at any moment; her colleagues were right outside the trailer; her mother's murder still weighed against her heart like an albatross; her whole life had not prepared her for this. For what she was about to do.

She rose from the seat, her hand squeezing his in time with his squeeze to the stress ball. She gave in to need and brushed the hair from his forehead. He opened his eyes.

Kate leaned in and put her lips to his ear, a tumult thundering through her body, aching to get out.

"When it's me, you'll never have to wonder."