Author's note: So I thought my last one would be as close to a post-finale Castle-fic as I got. Turned out that was wrong, and this fandom is addictive. So here is my second post-finale Castle-fic. This one will be multiple chapters (no idea how many at the moment, probably not a lot). The length got away from me a bit. And I would like to thank everyone who reviewed my last one. You were all very encouraging.

Disclaimer: Sadly these characters don't belong to me.

A Matter of Motive

"It's about your mother."

She'd been obsessing about those words for almost the past two weeks. Kept hearing them in her head during basically any quiet moment. And the second he'd said them she'd known, known that whatever he was going to say would turn her world upside down. Again. After she'd told him that she almost hadn't been able to right it after the last time. After she'd trusted him. And that was what had hurt the most. She finally, finally lets herself open up again just a little and he does the one thing she asks him not to.

"It's about your mother. I… I looked into her case file…"

"You what?" Really, she'd been impressed that she hadn't screamed at him. That she'd kept her voice so low, even if the venom and the hurt dripped from each syllable. So much so that even he'd heard it. It'd permeated his thick skull enough that the danger registered and he actually paused for half a second before continuing in his pathetic attempt to justify his act of betrayal.

"I know. Believe me Beckett, I know. But I'd already done it when you told me not to…"

When threatened, default back to sarcasm. "Oh, well in that case it's perfectly okay for you to go rummaging through my personal tragedy. I mean, since I hadn't actually told you not to then of course that's fair game. I know you think that because you're a writer it somehow gives you an excuse to butt into people's lives Castle, but…"

"Yes, I'm a horrible person. But…"

"Shut up! Just shut up! You don't get to talk now! One thing! I ask you one thing Castle! And you can't even…"

But then he'd interrupted again. "They found something."

Three little words. And he hadn't shouted them. Hadn't raised his voice. Really, he'd been very calm for the whole conversation. Probably afraid she'd shoot him. She'd been working herself into a state of righteous and completely justified fury, but when he said those three little words her world started closing in. The bustle of the hospital just fell away.

"It wasn't gang violence. She was targeted."

And then nothing else mattered. Not Will in the next room, not the man in front of her, nothing. All that mattered was stopping the millions of thoughts, of theories, of conspiracies, of motives, of possible scenarios from rushing into her brain and taking over. She couldn't do this again. Couldn't deal with the what ifs. Couldn't face the fact that someone had wanted her mother dead. That someone had deliberately destroyed her life. And yes, a small part of her couldn't deal with the fact that even though she'd spend countless hours staring at the file and coming up empty, this civilian had found something she'd missed. But mostly she couldn't deal with the panic. Panic over what would happen if she let herself get consumed again. She'd told him. She'd told him what had happened the last time. Told him she didn't think she was strong enough to go through that again. Not if she wanted to keep her sanity.

Out of the corner of her eye she saw him reach for her. "Beckett… Kate… Hey…"

"Don't touch me!" She bit out. "Don't you dare touch me!" He recoiled instinctively from the rancor in her voice. "Just get away from me." When he looked like he wanted to speak she beat him to it. "I trusted you. And I told you we were through if you did this. I told you. But you did it anyways didn't you? Guess you wanted that all important back-story. Well I hope it was worth it because that's all you're gonna get. Oh don't worry Castle. I know I can't force you to stop shadowing me, can't get you transferred. Not with you being buddies with the mayor and all. So you can still come around, follow me on cases, watch me interview suspects, come to the crime scenes. I can be professional. You'll see how professional I can be Mr. Castle. Because it'll be a cold day in hell before I tell you anything personal again."

She had a vague recollection of him trying to stop her, but she hadn't let him. She couldn't stay there any longer. Another minute and she'd be collapsed on the floor. And she'd be damned if she let him see her break. So she'd managed to get out of the hospital, and even back to her apartment. She'd even gotten he door closed and locked before she fell apart.

Her mother had been murdered. And she'd missed it. Somehow she had to figure out how to live with that, but she was worried she wouldn't be able to.

xxxxx

That had been almost two weeks ago. Thankfully she hadn't been called in for the rest of the weekend, and so had been able to spend it holed up in her apartment hiding from the world, dreading the start of her workweek. Of course, when Monday rolled around she managed to pull herself together enough to drag herself into work. She was not going to let him see her weakness, not ever again. But when she got here she was treated to unexpected thoughtfulness. Montgomery called her into his office and told her that they would be without the services of one Richard Castle for the next couple of weeks. She'd been surprised, but secretly a little relieved.

"He give a reason?" she couldn't help asking, wondering if he'd told the truth.

"Apparently his publisher's being difficult about the speed he's been writing at and he needs to buckle down and do some editing before they come and chain him to his laptop."

"Well, at least we'll have some peace and quiet around here," she'd told her boss, trying to keep the tone light.

"There is that." He agreed with her. "Hey. You okay Beckett?" he asked her suddenly.

"Fine sir." Oh god, he knew. Of course he knew. Castle probably told him someone needed to re-open the case.

"Because you know, things have been difficult for you lately, what with Agent Sorenson's shooting, and everything. If you wanted to take a couple of days…"

She cut him off abruptly. "I'm fine sir."

"Okay." As she turned to leave he stopped her. "But Detective, if for whatever reason you find this unit was running more efficiently with Castle gone, I could get him reassigned to someone else, the mayor and the commissioner be damned."

She almost smiled. "Thanks for the offer, but I think I can handle Mr. Castle."

"Well, if you ever change your mind."

"I'll be sure to let you know."

And with that her boss had simply nodded and gone back to whatever he'd been doing before she arrived.

If Esposito and Ryan thought Castle's absence odd they hadn't mentioned it. Well, not directly at least. After lunch she found the two of them hovering by her desk, and Ryan had casually mentioned that if anyone was ever causing her any trouble, well, between the two of them and Lanie he was sure they'd have no trouble disposing of a body so that it'd never been found. She'd grinned. She couldn't help it. Even if she declined their offer. She also couldn't help being pleased when she realized that they'd both stopped drinking fancy lattés and cappuccinos and had gone back to regular old coffee.

So she'd had almost two weeks to prepare herself, prepare to see him again. Two weeks to try and readjust her life. Try and live with the new reality of her mother's murder . Two weeks of calling Lanie, trying to figure out what she should do. Two weeks constantly tamping down on the anxiety that kept threatening to rise each time she thought about her mother. Two weeks of wondering what exactly he'd found that made murder more likely, and how exactly he'd found it. Because she hadn't asked him the details. But she couldn't ask him the details now… could she?

Lanie certainly had an opinion about that.

And why had he done it? In the first flash of anger and hurt she'd originally assumed it was for his book. For his new detective, trying to figure out what made her tick. But, now she wondered if it was something else. Something… different. After all, he had looked almost concerned when he'd told her, and he'd asked her to sit down, tried to break it gently. And before she'd left him, even though she couldn't remember much, she did remember seeing something that resembled hurt on his face in that brief second she'd let herself look at him before she'd shut down.

Unsurprisingly, Lanie had an opinion about that as well.

"He did the one thing, the one thing Lanie that I asked him not to. And I told him, what happened last time, why I could work on that case. I actually told him what happened."

"I know sweetie. And I know you trusted him and he hurt you, and he deserves to suffer for it."

"Damn straight he deserves to suffer."

"But does he deserve to suffer for the rest of his life?"

"Oh I doubt he'll suffer for the rest of his life Lanie. He'll move on, find something else. Once he's figured out Nikki Heat he'll be gone."

"You think that's all it was then? For Nikki Heat?"

"Why else? I told him. I specifically told him what would happen if he touched that case. What other reason could he have?"

"I don't know girl, you didn't let him explain. If the man had other reasons for doing what he did you didn't want to hear it. You want the details you're going to have to talk to writer-boy yourself."

"I don't know if I can."

"What's this? Kate Beckett backing down from a challenge. My hearing must be going because I know that's not what you just said honey."

"He did look upset… It think… maybe… I'm not sure."

"Of course that could have been just because he'd be losing a muse." Lanie pointed out slyly.

"Right. Exactly." But suddenly she wasn't as convinced that was true.

"Or it could have been he was worried about hurting you."

Lanie had to say it didn't she? Just had to say it. Wasn't it an unspoken rule that your best friend was required to side with you against a man, no matter what the circumstances? Still, the thought had crossed Kate's mind, in her more generous moments. "Maybe. Doesn't mean his motives are pure."

"Course not sweetie but that man cares about you."

"Sure he does," Kate remarked dryly. Lanie, god love her, wonderful person, but once she got an idea in her head it'd take more than a silly instance of personal betrayal to convince her otherwise.

"Now you're just being difficult. Any fool can see it, way he acts around you."

"The way he acts around me. Hah. That man would flirt with anything with ovaries that breathed."

"Somehow I've never noticed him flirting quite as much with me." Lanie couldn't resist pointing out.

"Probably because there's usually a dead body between the pair of you almost every time you meet."

"Never stopped you two. Besides you flirted back, don't even try and deny it girl."

"Of course I flirted back. I practically had to in self-defence!"

"Plus it's fun."

"Lanie…"Kate sighed.

"You were having fun girl, don't even try and convince me otherwise. And that's what makes this whole thing even worse." And Kate new she couldn't deny it. Sometimes Castle was fun, and it did make everything worse.

"It doesn't matter anyways. I can't ask him why he did it without talking about my mother's case."

"Which you still don't even know the details about."

"I can't ask him Lanie, I just can't. What if I…?"

"What if you what? Get eaten up worrying and obsessing about it? Girl you've called me almost every night for the past week and a half. I don't mind, you know that. I'm here for you, whatever you need. But, face it hon' you're already in it. At least if you talked to him you'd know what you were dealing with. I can't believe you've held out this long. And you know that whatever you decide I'll be here to pull you back from the ledge."

"Thanks Lanie."

"Hey, I know you'd do the same. Just think about this though. No question that man deserves a little punishment. Rick Castle hurt you; he broke your trust, which I know is hard for you to give and he poked his nose in somewhere he had no right poking it. Why'd he do it? I'm not sure, but I have an idea, and I think you do to. But truth is neither of us knows for sure. What did he find? Neither of us could even begin to guess. So until you suck it up and talk to him you're going to have more questions than answers. The way I see it you've got two choices, you can either ignore it, and when he shows up on Monday you make good on your threat to treat him with cold professionalism, or you go talk to him before that and get yourself some answers."

"Just like that huh? Just show up at his house one evening."

"Well, maybe leave the gun at home just in case."

Kate laughed. She couldn't help it. "Thanks Lanie. I'll think about it."

"You do that. And Kate,"

"Yeah?"

"I know it's not easy. Whatever you decide to do I'll respect that. You decide to go the ice queen route let me know; I'll be so cold writer-boy'll have to wear long underwear down to the morgue."

And even though that got Kate laughing again it didn't last long, because Lanie was right. She had two choices, storm over to his apartment and demand answers, or ignore it and deal with the awkwardness at work indefinitely. But what was she going to do, just show up at his apartment out of the blue? On the other hand, somehow calling him seemed so much worse. Ugh. When had things gotten so complicated?

xxxxx

Her dad was pining. No other word for it. Sure he pretended otherwise, but she knew, and Grams knew. Any cheerfulness was fake, he spent hours in his office not working on his book, and he'd very noticeably stopped talking about his new muse. She'd known something was wrong, but when she'd asked him he'd muttered something about his editor being on his case about editing, and something else about Detective Beckett being mad at him, and told her not to worry about it. It'd sort itself out.

Well, it'd better, because he certainly wasn't doing anything to sort anything. Unless you counted moping around the apartment in sweatpants, pretending he wasn't moping around the apartment, doing something. She'd almost called Detective Beckett herself to figure out what was going on until Grams had filled her in on the details. And then she couldn't, because it was pretty bad. Besides, it really wasn't any of her business. And let's face it, another Castle prodding around in the situation might just make it ten times worse and send the detective running in the other direction. So now she was stuck watching her father pretend nothing was wrong when clearly something was.

In two days he would go back the precinct for the moment of truth. And if Detective Beckett shut him out Alexis wasn't sure what would happen. Because her dad seemed resigned to his lot. And maybe he deserved some of what he was getting, but he'd been trying to help. Surely that counted for something? Besides, she'd never believe he deserved it completely. Kate Beckett had been special to Rick Castle. His daughter had seen that in a second, even if he'd denied that anything was going on. She'd just known. Call it daughter's intuition.

So when she got back from the movies on Saturday afternoon she knew she'd find her father in his office, pretending to work. Grams had some friends over, and they were unfortunately playing show tunes in the living room. She'd decided to forgo the free show and gone to check on her father.

"Hey Dad." She said as she opened the door. He was at his computer, but she was pretty sure you had to be actually typing for it to be considered editing.

"Hey pumpkin. How was the latest Harry Potter?"

"Not bad. They cut out most of the book as usual, but still not bad."

"Ah, light on the details and strong on the special effects as usual. And how are the girls?"

"Good. Same as always." She paused, "How're you?"

"I'm fine sweetie."

"You sure? Because I know you go back to the precinct on Monday and…"

"Don't worry about it. It'll be fine. Everything'll work out."

"If you say so."

"I do. And I'm your father, aren't you supposed to treat my word as law?" he asked her with a hint of a smile.

"That was last century. In this one I'm supposed to think everything you say is wrong, unfair and/or stupid."

"Right. Well, ignore that, in this case you can believe me."

"I just worry about you." She'd learned long ago that sometimes her father wasn't as tough as he pretended to be.

"I know sweetie, and I appreciate it. But I screwed up, and it's going to take time to fix."

"She'll come around Dad." At least she'd better. Or Alexis decided she might have to figure out a way to talk to Detective Beckett herself, good idea or not.

"I hope so, or I'm going to have to find another muse."

"She'll come around." She'd repeated, trying to convince both of them, knowing her father wouldn't be finding another muse any time soon. "If you need me I'll be studying in my room."

"But you'll miss out on the greatest hits of Cabaret?" He exclaimed in mock horror.

"One can only hope," she told him dryly.

"Smart girl."

She'd left him then, only to be met by her grandmother in the hall.

"How's he doing kiddo?" the older woman asked her.

She shrugged, "Same. Gram, are you sure there's nothing…"

"I'm sure. Much as I'd love to step in, and you know that usually I have no scruples doing just that, they've got to fix this themselves. Anyone interfering'll just make it worse."

Alexis sighed, she knew it was true. Didn't make it any easier to accept. "If you say so. I'll be in my room studying if you need me."

"I'll try to keep the volume low enough that your earplugs will block the noise."

"Thanks Gram."

Martha shot her granddaughter one last affectionate look as she watched the young woman head to her room. Then she glanced in concern at the door to her son's office. She hoped Kate Beckett had it in her to forgive, or regardless of what she'd just told Alexis, that woman was getting a visit from one Martha Rogers. She was his mother, and she wasn't going to let her son's heart get broken if she could help it.

Shaking herself out of her thoughts she went back into the other room just in time to start the second act.

Midway through the second act, but at a lucky break between songs, Martha heard a knock on the door. She went to answer it quickly. She wasn't expecting any more guests, but you never know. Besides, the more the merrier.

Still, she got a bit of a shock when she swung open the door to reveal one very nervous looking Kate Beckett.

"Hi Martha."

"Detective Beckett this is a surprise!" though certainly not an unwelcome one she thought to herself.

"Yeah. I know. I probably should have called, but I was in the neighbourhood," a complete lie of course, but it seemed easier than anything else, "and it was kind of a spur of the moment thing. Is he in?" But then the noises coming from the other room seemed to register in the younger woman's mind. "You're having a party. I'm so sorry. I'm interrupting. I should go…"

"Nonsense!" Martha cried. No way in hell was she letting this woman leave. She was going in that office if Martha had to drag her kicking and screaming, armed or not. "I'm just having a few theatre friends over for some drinks. My son's in his office. I'm sure he'd be more than happy to see you." Actually, that was probably an understatement.

"Oh well, if he's working I wouldn't want to interrupt…" But Kate didn't know why she even bothered. Martha already had her halfway to the door she knew let to Rick Castle's private office before she'd even finished speaking.

"I'm sure he'll be glad of the distraction. I'll just let him know you're here." She knocked on the door before the jittery detective had a chance to bolt. "Richard darling?"

Kate heard a familiar voice from the other side of the door, "Out of gin are we mother?"

"As a matter of fact we are, but that's not why I'm here." Martha told him as she opened the door. "You have a visitor." And with that she practically thrust the woman at her side into the room.

Castle looked up then. His eyes widening when he saw her.

"Hi." She told him.

"Hi." He replied, rising quickly and moving towards her before stopping abruptly about halfway across the room.

"Well, I'll just leave you to it shall I?" Martha told them brightly.

"Thanks Martha." Beckett told her quietly.

"Lovely to see you as always detective." The older woman replied before shutting the door. When she got to the other side she briefly considered finding something to barricade it shut with. Maybe she should ask Alexis for help. That girl usually had good ideas.

Back inside the office things were still a bit awkward to say the least. For his part Castle couldn't think of anything to say that wasn't idiotic, or, you know, that didn't involve basically throwing himself at her feet and begging her forgiveness.

Luckily she broke the silence first, "How are you?" she asked.

"Fine, you know, working."

"Right. I probably should have called…"

"No!" He practically shouted. "That's fine. This is fine. You're always welcome." Suddenly afraid that she was going to leave as quickly as she'd come he felt the need to say something, anything, as long as she didn't leave. "When I said I was working before… I was lying. I was really just pretending, so you're coming gives me a perfect excuse to take a break. If you can really call it a break since I wasn't actually working." Great. She comes to see him of her own accord and he was rambling. Just great.

Luckily she interrupted him. "We need to talk."

Castle sighed, here it comes. He should have expected this. She was here to give him the old heave ho, probably figured it'd be kinder to let him down in private than in the middle of the office in front of everybody. "Yeah," he told her resignedly.

"So why'd you do it?"

"What?" Well that wasn't what he'd been expecting.

"I need, I need to know why you did it. I mean, I told you…" she took a shaky breath before continuing, "I told you what would happen if… after what had happened last time…" she trailed off, looking at him expectantly. "I need to know."

And that was when he realized, there was still hope. He might still be able to work his way back into her good graces. He just had to tread softly, and hope natural charm coupled with the truth was enough. So he braced himself for her reaction, and told her. "Why? Well that's easy Detective. Because I care about you."

xxxxx

TBC