A/N: Castle belongs to AWM and ABC. Many thanks to Joan for being an amazing beta, and Anja for being the bestest cheerleader ever. Prompt at the end.

He got the text on a quiet Sunday evening.

His daughter had already said goodnight, his mother was God knows where, and he had spent most of the afternoon getting a surprising amount of writing done. Heat Rises was going to be the best Nikki Heat book yet, he could feel it, even if he still didn't have the ending set in stone. He was now indulging in a finger of scotch and a mindless video game in preparation for an early night. They had closed their last case on Wednesday evening, and while their team was on call, his presence hadn't been required at the precinct since then. He had every plan to come in in the morning anyway, even if it was just to bring his partner a cup of coffee – any excuse after four days without her.

So it was a surprise when his phone buzzed with a message from her a little after 9.30pm.

Come over?

His eyebrows shot up at the request, but he was pushing up out of his seat even as he typed his equally brief reply.

On my way.

Pausing to scribble a note for his daughter which he left on the kitchen counter, he patted his pockets for his wallet and slipped his phone and keys in, too, before donning shoes and a coat and heading out. Hailing a cab was surprisingly easy at this time of night, and less than five minutes after her initial request he was being whisked through the after-dinner crowd toward her apartment.

The cabbie let him off at her corner, and he made sure to include a generous tip as he thrust cash through the plastic barrier. He exited the vehicle, and found his hands were shaking so he crammed them into his coat pockets as he made the short walk to her building, all the while muttering to himself about how silly it was to be nervous. Okay, so he was fairly certain he was irrevocably in love with the woman. Okay, so he generally avoided dropping in on her in the evenings for fear of running into Doctor Motorcycle Boy. Okay, so the hour and unusual summons meant that whatever she needed him for was, at the very least, important. Yet it hadn't sounded urgent. Still… It wasn't until he was standing at her door with one fist raised to knock that he allowed his mind to dwell on the fears that had been plaguing him since her text arrived. What if she was in trouble? Or hurt? What if she had bad news?

What if she had decided she didn't want him following her anymore?

He shook his head at this last one. It might be one of his deepest fears, losing her and the purpose his work at the 12th had given his life, but ever since she had told him she didn't mind him pulling her pigtails after everything went down with Coonan, he was fairly certain she actually wanted him around. Even if Josh himself – whom Castle strongly suspected loathed his presence in Kate's life almost as much as he loathed Josh's – even if Josh made an ultimatum, Castle was secretly hopeful that his own position in Kate's life was stronger, surer… but that was only a hope. He couldn't be sure, and he might be completely wrong.

Yet the Kate who answered the door – and there was no trace of Beckett about the luminous if hesitant smile she greeted him with, nor about the oversized sweater, yoga pants, and purple toenails she was sporting – did not appear to be in any sort of mortal peril. Still, at second glance there was an unusual droop about her shoulders, so he stifled the quip on the tip of his too-ready tongue, and led with an innocuous but heartfelt "Hey."

"Hey, Castle," she replied softly, moving aside so he could enter.

He paused once he was inside, letting her take the lead on both conversation and destination. Sure enough, she closed the door and moved past him into the kitchen, and he followed, hovering at the end of the island where he could be near her but there was still the illusion of a barrier between them.

"Wine?" she asked, pulling down a single glass. A quick visual sweep of both kitchen and living room betrayed no sign of her own glass, so he shook his head.

"Maybe later," he replied, and she set the glass on the counter before her, bracing herself with both hands and letting out a deep breath with a whoosh of air.

"I should have called Lanie," she muttered.

He studied her for a long moment. She looked… vulnerable. It was a word that sat uncomfortably with him, because the Kate Beckett he knew at work was indomitable. Yet tonight she was fragile, and worried. His heart clenched at her words, longing to discover what was wrong so he could help fix it, but he refused to push her. Not in this state.

He didn't let his voice betray his thoughts, however. "Do you want me to go?"

"No. No, Lanie would ask too many questions, and I don't think I could handle that kind of interrogation right now." Her brow was furrowed, her luminous eyes full and sad, and he had the sudden thought that if he so much as breathed too heavily, she would completely crumble.

He yearned to gather her up in his arms. "Kate, what's wrong?"

A blush stained her cheeks. "I'm late," she said, so softly he almost didn't catch it.

"Late? As in...?" his voice trailed off as he filled in the blanks for himself. He felt winded, like he had been kicked in the stomach. "You're pregnant?"

She turned to face him, her eyes so full of understanding that he dropped his. "I don't know. I have to take a test, but..." She glanced down at a pink box he hadn't yet noticed, half-hidden behind an empty fruit bowl on the far end of the counter.

It took him a moment to swallow the sting of disappointment, to push away his rage at how unfair it all was. She was his friend, and she needed his support right now. "You wanted someone here with you while you take it?" he guessed, and the grateful look she sent him confirmed it.

"Do you mind? I just... Lanie would be too much to deal with right now and Josh is on shift. I know it's super awkward and everything but..."

Resolutely suppressing the burn of jealousy, he nodded. "What are partners for?" he asked, and she smiled this time. "Kate, just so I know what we're rooting for here, is this something you and Josh have... planned? Would a positive result be a good thing?"

She dipped her head, allowing her hair to fall forward, hiding her face from his. "We haven't talked about it." At first it seemed like that was all she planned to say, but then she continued. "We haven't talked about much, really. I don't know how he would feel about it. I'm not... I've never been much of a baby person, and I figured if I did ever go down that path, it would be with my husband, you know? Not…" She made a dismissive gesture, almost growled, paced away and back again. "Josh and I aren't... We both care too much about our jobs to be really serious about our relationship, and even though he didn't go to Haiti... we've been fighting more and more, and I just... I don't know."

"Would you keep it?"

She paused for a moment, as if choosing her words. "I think so? I mean, it's not ideal, but I don't think I could go through with getting rid of it. I just don't know how I'm going to make it through on my own."

"You don't know for sure he doesn't want it." He was trying for comforting, but his words tasted like ashes.

She glanced up at him, firm on this point. "But I do know for sure that he's not who I wanted to be going through this with. A baby isn't a good reason to stay in a relationship with someone when nothing else is working between you."

He decided to aim for levity, anything to distract from the weight of her announcement. "I wish someone had told me that when Meredith was pregnant."

She smiled, a broken, aching thing. "If I really am pregnant, I hope I'm even half the parent you are."

He reached across the counter, covering her hand with his, ducking a little to catch her eyes. "Kate, you're the strongest person I know. If anyone can handle this, it's you."

Her lips twitched appreciatively, but her forehead was creased in deep thought. After a long moment she raised her eyes to meet his, her expression akin to the proverbial deer in the headlights. "Castle? What happens if... if the person who I've realised I really do want to be with doesn't want me because... because I'm having another man's baby?"

His heart, which had been splintering into piece after piece, gave a sudden kick as if life had been breathed back into it. Did she… could she possibly mean him? Or some generic person in the hazy future? Yet her eyes were intent as if willing him to understand. He chose his words carefully, hoping that she understood what he was really trying to say. "If he's worth it, if he loves you the way you deserve to be loved, he won't be able to help loving that child because he or she will be a part of you. Just like I hope that the next time I get married, for keeps this time, that she will adore Alexis in spite of who Meredith is to our family."

Something flared in her eyes, something soft and hopeful, like the clouds rolling back to allow the sun to peek through. She took a deep breath. "Well, if there is a baby, he or she could do a lot worse than turn out like Alexis."

He plastered on a bright smile. "And let's face it, you and Josh would create a super species of baby. You're both entirely too perfect," he said, a little afraid his own jealousy was showing. But she was staring up at him with soft eyes and a gentle smile, and a breathtaking vision of her holding her child arose in his mind. He wanted that for her; he wanted that with her, and it was all he could do to not beg her to make promises he couldn't possibly hold her to while she was still in a relationship with another man.

Instead he forced himself to break the moment, to put her - them both - out of their misery. "Okay, enough talk. You go take the test. I'm going to make us some hot chocolate. And whatever happens, Kate – whether that stick reads positive or negative, whether you dump Dr. Motorcycle Boy on the spot or settle down with him, I just want you to know I will be here for you in whatever capacity you need me."

She bit her lip, looking up at him. "Thanks, Castle. You- you're a better friend than I deserve."

"I'm just your partner. Comes with the job description. Now, go!" he said, making a shooing motion.

Squaring her shoulders into something a little more recognizably Beckett, Kate picked up the test and headed for the bathroom, even as Castle began busying himself around the kitchen. He wasn't aware of her pausing in the doorway until she turned and spoke.

"Castle?"

"Mmm?" It took him a moment to glance up.

"Thank you."

He smiled at her, in spite of his heart being in his throat. "Always."

He was just pouring the steaming hot chocolate into two mugs when she emerged from the bathroom carrying a little white plastic stick. He watched her hovering out of the corner of his eye as he finished, placing the empty saucepan in the sink before turning to face her.

"Well?" he asked.

Her face broke out into a smile. "Negative. And… well… definitely negative."

"Oh, thank God." Relief washed over him. He would have been happy for her, and supportive, but oh, God, he would have always been just a little jealous at the idea of Josh having a permanent place in her life. In three steps he was beside her, wrapping her in a hug before he knew what he was doing. She didn't seem to mind, though, burying her face in his shoulder.

"I'm so sorry I dragged you into this for nothing, Castle," she said, her voice muffled.

He cradled her to him, memorizing the feel of her in his arms, relishing the ability to comfort her. "Don't be. I'm glad you asked me to come. I will always be here for you," he vowed.

Eventually she pulled away, sliding onto one of the bar stools at the breakfast bar and helping herself to one of the mugs. He didn't realise he was staring until she quirked an eyebrow at him, and he jerked forward to join him.

"I guess I better arrange to see Josh so I can give him the bad news," she said after a contemplative silence.

He looked at her, his mug halfway to his lips. He raised his eyebrows. "Bad news? I thought you were relieved?"

She shook her head. "Not about the pregnancy scare. He doesn't need to know about that. No, I need to tell him it's over. It's been over for a long time."

Schooling his features, he took a sip of his drink, carefully not looking at her. "Oh. Right. That's too bad." He wasn't sure his tone was convincing, but at least it mostly hid his elation.

"Castle."

She was glaring at him, although her lips were twitching. Okay, maybe he hadn't hidden it that well.

He blinked at her innocently, and she just rolled her eyes, going back to sipping her drink.

He took his courage in both hands.

"What then?" he asked cautiously.

"What do you mean?" Color was creeping up her cheeks, so he was pretty sure that she knew exactly what he was asking.

"Well, if you're serious about ending things with Josh, we'll both be single," he said meditatively, gauging her reaction out of the corner of his eye.

She hummed noncommittally, taking another sip. It was an invitation. (He hoped. Even now, after all this time, it was hard to read her.)

"Do you think, maybe…" he began, but floundered and looked at her helplessly.

She drained her mug and stood, patting him on the shoulder. "I'll tell you what, Castle. Give me a chance to talk to Josh first and get that… done with. And then how about we have hot chocolate again, and you can finish that question. Sound good?"

"Sounds amazing," he said, watching her move into the kitchen and rinse out both her mug and the saucepan. His throat clogged up with all the things he wanted to say to her but couldn't until after she broke things off with Josh. She held out her hand for his mug, and he drained the dregs before handing it to her. She took it, using the action to close her hand over his for just a moment.

"Thank you for tonight, Castle. I don't know what I would have done without you here."

He smiled at her, rising to leave before he did something dumb like kiss her while she was still technically with another man. "You would have made it through. But I'm glad I could help in some small way."

He paused at the door, glancing back to find she had drifted up behind him.

"I'm really looking forward to our next hot chocolate, Kate."

"Me, too," she said with a soft smile, and he watched her close the door behind him.

Prompt: S3, Kate has a pregnancy scare and asks Castle to 'hold her hand' through taking the test, in spite of it being Josh's potential baby.