Disclaimer: All things Castle belong to AWM and the other powers that be at ABC.

Author's Note: Written after watching "Knockdown" for the billionth time because it remains one of my all-time favorite episodes. An episode insert for when Beckett goes to see Castle at the beginning, building on the deleted scene in the loft, because I always thought more needed to be said than was shown in the deleted scene.

Partners

Castle turned away from the electronic story board for the next Nikki Heat book with a brief sigh of frustration. The plot wasn't coming together, not really. He had the bare outlines of a story coming together—a priest found dead in scandalous circumstances, something to do with an old crime confided to the priest as a person to trust, the resulting cover-up—but he knew there needed to be more. Coming up with the bare outlines—the dead bodies, the murder scenes—that was the easy part. The hard part, always, was coming up with the real meat of the plot, the overarching story line, the emotional thread to tie everything together.

And of course Nikki and Rook's relationship. He knew he needed to do something with that, throw a spanner in the works of the relationship that would serve as the impetus for a deepening of the relationship into something more than the rather-casual dating thing Nikki and Rook were doing. He'd come up with one minor thing with having Rook disappear for an extended amount of time on an assignment but that was an easy issue, one quickly resolved. He briefly toyed with—and almost immediately discarded—the idea of another woman but no, he couldn't do that. The Nikki and Rook relationship might be fictional but just as cheating was a red line for him, he couldn't imagine writing about it as something that could be dealt with and then moved past and he certainly couldn't imagine using it as a springboard to deepen the relationship between Nikki and Rook.

He turned the screen off and glanced out the window, pondering going out for a walk, getting some fresh air to clear his head. The blank page on his laptop screen was taunting him so he closed that too, picking it up and going out into the living room with the vague thought that maybe a change of scenery, even if it was still inside his own apartment, would help.

And wondered what Beckett was doing. It was an off day for her, one where she didn't even need to go into the precinct—hence why he'd been at the loft all day, trying to plot out Nikki Heat—and the team wasn't due up to be called if a body dropped either. He looked at his cell phone, severely tempted to text Beckett just to see what she was up to, tried to come up with some casual, non-threatening excuse to see her.

He grimaced. He always wanted to see her. It frankly terrified him sometimes when he thought about how much he wanted to see her, this constant desire—no, need—for her presence, to see her smile, to talk to her. A small, twisted part of him had almost gotten to the point of hoping for bodies to drop, just so he could see her—almost. He did feel… happy… whenever she called about a case and he felt vaguely guilty about that, too, since a case always meant that someone had been murdered but he couldn't help it. He wasn't happy about the murder, only about seeing Beckett, and it was just his twisted luck that he so rarely saw Beckett when a murder wasn't involved.

He was in love with Kate Beckett. That was so glaringly obvious he didn't know how he'd thought he could deny it or somehow make the feeling go away by staying away from her all of last summer in the Hamptons or by staying with Gina as long as he had. As if Gina—as if any other woman—could ever possibly compare to Beckett. He couldn't imagine it—and he had a damn good imagination. And that was really what frightened him, that he was so sure that no woman could ever compare, more, that he would never not be in love with Kate Beckett. It should have been ridiculous—he could almost laugh about it—that he, Richard Castle, who'd had more meaningless flings than he cared to remember, was so positive that he would always be in love with Kate Beckett, a woman he had yet to kiss. And yet somehow, he was sure of it, with the sort of certainty that had until now been reserved for his feelings for Alexis and his mother. His love for Alexis, for his mother, were as much a part of him as the color of his eyes, a fundamental part of him that could never change. And now, he suspected that loving Kate Beckett had somehow become part of him too, another truth of his life that would never change. He was going to love Kate Beckett for the rest of his life.

Beckett, who had a boyfriend—Dr. Motorcycle Boy, he reminded himself with a grimace. He didn't get the impression that Beckett was all that serious about Motorcycle Boy; she didn't seem particularly invested in that relationship. But then again, he could just be telling himself comforting lies because really, how would he know? Beckett wasn't the type to talk about her personal life.

The sound of the doorbell startled him from his thoughts, distracting him as he wondered who on earth it could be. It was the middle of the afternoon on a weekday; Alexis was at school; his mother was at her acting studio. Most of the adult population was at work.

He opened the door and for half a second, considered the possibility that thinking about Beckett had managed to conjure up her presence at his door. "Beckett," was all he could say.

He felt the spike of gladness he always felt at the sight of her that was immediately drowned out in a wave of apprehension. Something was wrong. Because Beckett didn't seek him out, didn't come to his home, when they weren't on a case.

And more than that, now that he looked at her, he could see it. There was something… off… about her expression, shadows in her eyes. She looked pale, troubled.

She looked… lost was the only word he could come up with. And it was so wrong on so many levels to see Detective Kate Beckett, who was smart, confident, capable, and the strongest person he'd ever met, looking like that.

"Hey."

Castle made a welcoming gesture and remembered, belatedly, that he was still holding his laptop. "Come on in."

She hesitated—another uncharacteristic thing—and then asked, "Could we talk for a second?"

As if there was ever any question about that. As if he wouldn't drop anything and everything to talk to Kate Beckett on a normal day, let alone on a day when she looked vulnerable. He bit back all the reckless words, promises, he wanted to blurt out and just stepped back from the door.

She stepped inside, glancing around. She didn't take off her coat, only her gloves.

"Sorry to bother you," she said after a moment and for a second, she sounded more like herself.

"It's no trouble. I wasn't really being productive anyway," he answered immediately, putting his laptop down on the living room table as they passed it. He wanted to ask her what was wrong, why she'd come to him, but he knew Beckett—or was learning to know her—and often, direct questions like that only made her shut down. And she looked unlike herself enough that he was going to be careful and respect her boundaries if it killed him. He didn't want to scare her off the first time she was turning to him over a non-case related problem.

"Where's Martha?" she asked.

"At her acting studio." He tried to sound like this was just normal small talk, like he wasn't tensing more with every second.

She slid onto one of the stools at the island and he moved into the kitchen. "Do you want anything? Coffee?" he offered.

She shook her head a little tiredly and his heart hurt at the look on her face. She was trying to keep her usual invulnerable mask on—he knew her well enough to recognize it—but the façade was showing cracks. Her face was pale, her eyes bleak. She looked down at the counter, one of her fingers tracing an idle pattern on it, and he could practically hear her thinking, could certainly sense her preoccupation and her tension.

He wanted to put his arms around her, wanted to hold her and tell her that he would do anything for her, always, that she wasn't alone, that whatever this was, they could get through it together. But that wasn't what they did, that wasn't where they were in this friendship/partnership of theirs.

She was silent for another minute or so, not looking at him but looking down at the counter still as one of her hands dropped down and started fidgeting with a button on her coat.

Fidgeting! Beckett didn't fidget. He'd never seen her act anything other than decisively. It was something he loved seeing, the efficiency and simple grace of all her actions, her usual crisp confidence.

But now Beckett was fidgeting. And he was getting more uneasy by the second and the silence was wearing on his nerves.

"You sure I can't get you anything?" he offered again, more to break the silence than anything else.

She glanced briefly up at him. "I'm fine, thanks, Castle."

She was clearly not fine but he bit back that automatic response.

He opened his mouth to ask if she wanted him to call anyone—Lanie or one of the boys or Captain Montgomery even—but then closed it again. She was perfectly capable of calling them herself if she'd wanted to talk to them. Instead she'd come here. To him. He frowned a little. Not the boys, not Captain Montgomery—and he would have sworn that Beckett's usual first instinct when anything happened was to contact the precinct, her team. Whether it was case-related or not, he knew either Esposito or Ryan would have done whatever Beckett asked; the boys had her back and she had theirs. And they were cops, had access to information he didn't have, training. Unless—he mentally paused—unless of course whatever was bothering Beckett was something that cops couldn't deal with for whatever reason. And so she'd come here, to talk to him. A non-cop but still someone she could trust.

A non-cop that was trustworthy. Hmm. A niggle of an idea for Nikki and Rook formed in the back of his mind at that but he pushed it aside. He would figure that out later. Beckett came first.

"Beckett," he began again, cautiously, "is something wrong?" He paused and then asked with sudden concern, "Did something happen to your dad?" He wasn't quite sure why Beckett would have come here to see him if anything had happened to her father considering he'd never even met the man but something happening to her dad also seemed like the best candidate for what could have upset Beckett so much.

"No, not my dad." She hesitated and then finally looked up. "It's about my mother."

Her mother. Her mother's murder. Of course it was about her mother's murder. What else could possibly make Kate Beckett look so shaken, so vulnerable? He had a sudden flash of memory from a year ago—the pressure of the gun jammed into his side, Dick Coonan's cold, taunting voice saying "You'll never touch him," the look on Beckett's face as she fired her gun and saved his life, Beckett crying as she tried to revive Coonan. He inwardly flinched a little. He never wanted to see Beckett crying like that again, never wanted to see Beckett crying, period.

"What happened?" he asked as gently as he could. She'd refused something to drink but he handed her a mug with some water in it anyway. He wished he had coffee ready but at this hour of the afternoon, he didn't.

"I just got a call from Detective Raglan. He was…"

"The lead detective on your mother's case," he finished for her quietly. "I remember." He did. He remembered just about everything she'd ever told him but more than that, everything he'd read in Johanna Beckett's case file, everything Dr. Murray had told him, was emblazoned on his memory.

Her lips twitched a little, some color, some warmth returning to her eyes, her face, at his words.

"What did he say?"

She looked down, bit her lower lip—and for the first time ever, he saw her do that without wanting to kiss her, too distracted and worried for that—and then back up at him. "He said that he wanted to meet, that there was something about my mother's case that I didn't know."

"You know your mother's case better than anyone," he blurted out automatically because it was true. It had to be. He remembered what she'd said, how she'd spent years going over every line, every detail, looking for something the cops missed, and how hard it had been for her to finally put it away. Until he had dug it up again in his own stupid, blind curiosity and need to know, even if it had also been mingled in with a more justifiable wish to help her—he felt a surge of guilt rising up inside him like bile as it always did at the memory of how he'd dug into her mother's case, done the one thing she'd specifically asked him not to do. He looked at the tension in her frame, the shadows in her eyes, and wanted to kick himself all over again. He wasn't normally given to regret, to self-flagellation, but when it came to Kate Beckett, he was discovering new sides of himself, discovering every day that she was different, she made him different.

"I thought I did. But…" She trailed off and sighed, slumping forward over the counter in an uncharacteristic posture of despondence.

He had to lock his knees and grip onto the counter to keep from going around it to pull her into his arms, had to bite his tongue to keep from blurting out that he would do anything for her.

She looked back up at him and her lips twitched into an attempt at a smile. "You might have picked the wrong cop to base Nikki Heat on. I might not be as good as you thought. Maybe I missed something. I must have missed something, right?"

"Kate," he breathed, her first name that he so rarely used slipping out without thought at this unusual admission of self-doubt, of vulnerability. And while he wished, fairly often, that Beckett's protective walls weren't quite so strong, wished that she didn't always feel the need to be so strong, now, when she was vulnerable, he suddenly found that he hated it. Hated seeing her like this. It was paradoxical—he wanted to know she trusted him enough to be vulnerable around him but at the same time, he hated seeing her vulnerable because it meant she was hurting and he never, ever, wanted Beckett to be hurt. "You're a great cop, you know you are. Captain Montgomery always says that you're the best detective he's ever seen and for what it's worth, I know you're the best cop I've ever met."

She managed a small ghost of a smile. "How many cops have you met?"

"Over the years? Lots," he admitted. It was true, too. He had talked to, interviewed, lots of cops before in the name of research, early on in his career, trying to learn some of the nitty-gritty details of what went into criminal investigation. He'd chatted up the cops that were around when he'd been arrested (once he'd sobered up) and had then used his experience of being arrested in his books. Sure, he'd said he needed to shadow Beckett for research purposes—and at first, it really had been fascinating and a great source of inspiration and ideas to see how murders got solved—but it hadn't really been about research, not even from the beginning. Not really. He could have gotten the necessary research over and done with in a matter of weeks but he'd kept coming back, had not been able to stay away—and that was because of her. Because he'd wanted her. And then because knowing her had made him truly realize the value, the importance, of solving crimes, of bringing closure to the victims' families. His books, of course, always ended with a case solved, with justice, but he'd never before realized how important that was, how much it meant. Had never considered the wound an unsolved crime inflicted on the victims' families—until he'd met her and seen how much she still hurt over her mother's unsolved murder.

"You're a great cop, Beckett," he repeated. "Whatever Raglan wants to tell you, it can't be anything that was in your mother's file or you would have seen it, noticed it. Remember, Raglan wrote what was in your mother's case file as the lead detective so he knows what you know about the case. So if there's something about your mom's case you don't know, it can't possibly have been in her file so it's not that you missed anything."

She gave him the faintest quirk of a smile. "That's surprisingly logical reasoning for you, Castle."

He shrugged a little and managed a facsimile of his usual grin, more relieved at this first flash of the usual Detective Beckett snark than he could express. "I can be logical when I want to be," he returned.

"I've seen no evidence of that until now." Yes, Beckett was more like herself now, her tone approaching normal for their usual banter.

Thus reassured, he sobered. "Did he say anything else about why he wanted to talk to you?"

She shook her head.

"And he wants to talk to you alone?"

She nodded. "He was clear about that. He said just me, no cops. We're meeting at a coffee shop on 4th and Main in…" she glanced at her watch, "just about 30 minutes."

"And you're sure it was Raglan on the phone?" he asked, not because he really doubted it but because he didn't want to believe it. Didn't want to believe that her mother's murder was again threatening her peace of mind, bringing back all her remembered hurt and anguish over her mother's death. He knew she wanted, needed the answers—the why of her mother's death—but he also knew, could see on her face, how hard it was for her whenever her mother's case came up again.

She gave him a look and nodded. "Yeah," was all she said briefly but it was enough. He had no doubt that Beckett remembered every detail of that night—January 9, 1999—as if it had happened yesterday, could remember not just Raglan's name and his voice but what he'd been wearing that night and every word he'd spoken to her.

And Detective Raglan had just contacted her. Something she didn't know about her mother's murder. His stomach clenched, suddenly feeling like all the blood in his body had turned into ice water. No, this could not possibly be good. And it was going to hurt her. He swallowed, pushing aside his emotions. He needed to think now, needed to be clear-headed. For her sake.

"Didn't he go over her case with you years ago?"

She nodded. "He did," she said briskly. It was a show of strength, of invulnerability, her brief moment of weakness passed. Typical Beckett.

"So if he had something to tell you, why wouldn't he tell you then?" He didn't expect her to have the answers, was just thinking aloud now.

"I don't know," she said quietly and for just a moment, he saw the emotion, the dread, flickering in her eyes.

"Why would he call now after all these years?"

"I don't know," she said again, meeting his eyes. He knew she knew he was just asking the questions rhetorically but she was answering them anyway, his questions mirroring what hers were, just to see if anything would spark from talking it out.

Something must have changed—but he couldn't imagine what. Johanna Beckett's murder was a cold case; no one aside from Beckett herself was working on it anymore and Dick Coonan, the man who'd actually done the killing, was dead.

"And he wants to see you alone, no cops," he said slowly. No, that wasn't good. "Isn't that when you surround the building with cops?" he asked. He knew enough of NYPD protocol to know that. When someone—a suspect and in this situation, under the circumstances, he didn't doubt that Raglan was suspect of something, of deliberately holding something back from Johanna Beckett's case file, as seemed likely—said to go alone, that meant going with enough cops to invade a fortress, eyes on every inch of the place. He didn't need to ask if she planned to go alone like Raglan had said; he knew she did. In any other case, she wouldn't—she wasn't a rule-breaker—but for her mother's case, she would. To say nothing of the fact that if she had planned to bring back-up, she wouldn't be here talking to him, would have called the boys and been at the precinct.

"Look, Castle, I know that I'm ignoring every tactical guideline in the manual," she began, her eyes glinting green with sudden determination, "but if Raglan can give me some answers, if there's even a chance…"

"I'll get my coat," he interrupted her, leaving the kitchen immediately.

He knew her, knew how hard it was for her to ask for help. He knew she probably would never have asked him directly to come. But he also knew that if some part of her hadn't wanted someone to go with her, she wouldn't have come here, to talk to him.

He shrugged into his coat, grabbing his keys, wallet, and phone before he turned back to face her. "We should probably leave in the next five minutes if we want to make sure we get there on time," he said, trying to sound confident, assured, as if there was no doubt that they'd be going together, as if he hadn't just invited himself to a private meeting.

She was looking at him, an odd expression on her face.

"What?" he asked.

"Raglan said he just wanted to talk to me," she said after a moment but there was just a little bit more color in her cheeks so she no longer looked as pale as she had been, a little warmth in her eyes as she looked at him, the set of her mouth softer.

He shrugged a little. "I'm not a cop. Besides, I don't listen to instructions, remember?" he said, trying to sound his usual insouciant self, although he knew it fell flat. He sobered, dropping his own façade as he met her eyes. "I won't let you talk to him alone."

She managed a pale imitation of a smile. "Thank you."

It was amazing how those two words could suddenly knock the breath from his body. From anyone else, to anyone else, the two words wouldn't mean much but from her, at that moment, they meant… almost everything. He didn't doubt that if she really wanted to, she would tell him to stay behind and after the lesson he'd learned in prying into her mother's case in the first place, after it was his fault that Beckett had to shoot Coonan before learning anything more about her mother's death, he would listen. When it came to her mother's case, he would listen. He remembered again what he'd said to her a year ago when Jack Coonan's case had first come to them, that he would do anything that she wanted, including nothing, if that was what she wanted—he'd meant it then and he meant it now.

But she wasn't telling him to stay behind, to let her do this alone. She was letting him come with her, was trusting him, relying on him to be by her side as she went to talk to this man who would be a stark reminder of the worst night of her life.

She trusted him—and he suddenly knew that, with the exception of Alexis's love and trust, this was the thing he was proudest of in his life, the most precious accomplishment of his life. To have earned Kate Beckett's trust.

"I'm your partner," he finally responded simply and wondered if she could see what he meant, all he felt for her, in his face, hear it in his voice.

If she could, she didn't let on. "My partner," she repeated as she stood up, giving him a look he couldn't quite read but one that still managed to make him feel a rush of warmth in his chest.

He was her partner. And he would have her back, he thought, as he followed her out of the loft. He would have her back for this, for whatever was going to happen with this latest wrinkle in her mother's case.

Because she trusted him and for now, that was enough.

~The End~

A/N 2: And we know what happens after this, the scene in the coffee shop with Raglan and everything else leading up to The Kiss. I just wanted to write out Beckett talking to Castle about the call from Raglan because the mere fact of her going to see Castle after that is still one of my all-time favorite Caskett moments.

Happy belated New Year, everyone. I hope 2015 is shaping up to be a great year.