Disclaimer: All things "Castle" belong to Andrew Marlowe and the powers that be at ABC.

Author's Note: A sequel to "Feels Like Home," so you should read that first, following Castle and Beckett through Season 3, although I don't plan to deal with every episode in the season. It turned out I couldn't resist the chance to play with Season 3 since it's my favorite season.

Starting with a prologue, set in the summer before Season 3.

Diving Into It Together

Prologue

Kate Beckett was not in a good mood.

Kate couldn't quite help but scowl as she entered her apartment and stepped out of her heels, leaving them carelessly by the side of the door.

It had not been a good day.

They had closed their latest case today but in the final takedown, the killer, a thug affiliated with one of the gangs, had shoved her into a brick wall before Espo had tackled him so she was a little bruised. More than that, she was annoyed at herself for letting the perp push her aside like that. She hated the times when the sheer fact of her being female and therefore lighter than most men got in the way of her doing her job.

Then, in being shoved like that, one of her favorite leather jackets had gotten torn by the bricks so she thought the jacket would end up being a loss.

She'd tried to make coffee for herself using Castle's espresso machine in the precinct and gotten a minor steam burn on her fingers when the machine, as per usual, expressed its displeasure at her being the one to use it. (Stupid biased machine. And it was annoyingly impervious to any of her glares and annoyed mutterings. If she didn't know better, she would wonder if Castle had done something to rig the machine so it wouldn't work properly for her, ensuring that she needed to keep him around if she wanted a proper supply of coffee throughout her day. Maybe he'd bewitched the damn machine. Bewitched! She let out another annoyed huff. She had clearly spent way too much time with Castle if that was the sort of thing she was thinking.)

And then to top off her bad day, someone had already taken the spot she usually parked in by the time she arrived back at her apartment so she'd needed to park an extra five blocks away from her place, which, while not that big a deal in the greater scheme of things, was just one more minor annoyance in a day filled with annoyances.

So no, Beckett was not in a good mood.

She was also tired, which didn't help anything. She hadn't slept well the night before. Or the night before that. Or—oh, who was she kidding, she hadn't really slept well for the last two weeks. Or the last 16 days, 11 hours and 39 minutes, give or take.

Not that she was counting.

Fine, yes, she was counting. She couldn't seem to help counting, her mind automatically keeping track of the days, the hours.

Bother.

She huffed as she went into her bedroom and changed into sweats and the over-large t-shirt she'd appropriated from Castle during her stay at the loft. Yes, she'd been deliberately choosing to sleep in his shirt. It was comfortable and soft from repeated washings, that was all. No deeper meaning to it than that.

Liar, a little voice in her mind spoke up.

Kate directed a glare at the voice in her head (that, predictably, had no effect whatsoever.)

She was fine. She was just fine. Really, she was. She had managed on her own quite successfully before Castle had come along and she could certainly get by just fine without Castle for a couple weeks. She was strong, independent Detective Beckett; she didn't need a man in her life to take care of her.

She didn't.

Of course, she had to admit albeit rather grudgingly, it wasn't about needing a man—needing Castle—to take care of her. Not even Castle would have dared tell her that she needed him around to take care of her.

But she did need him. She needed Castle to… make her happy. It was as simple and as complicated as that.

She missed him, damn it. Dratted man for wriggling his way into her life and then somehow infiltrating every corner of it with his smiles and his eyes and his humor and his loyalty. And if ever she'd needed proof of just how true it was that having Castle around made her work—her life—more fun, the last two weeks—16 days—since he'd left on his book tour had proven it.

Since he'd been gone, her life had mostly returned to the usual routine it had followed for years before she'd really met Castle, revolving entirely around work. Her evenings were once again quiet and predictable, consisting of her eating takeout in solitary splendor in her apartment, usually with a book. It was all almost exactly as her life had been before Castle had shown up. Organized, quiet, peaceful.

And she hated it.

For someone who had spent her entire adult life living alone and had always believed she liked it that way, it was a little stunning to realize that she'd been wrong all this time. Or more accurately, to realize just how much she'd changed over the course of the couple months she'd stayed at the loft, how much she'd changed since meeting Castle and, yes, falling in love with him.

Oh, she'd liked having her own space again when she'd moved into her own apartment but she was finding that having her own space, time to herself, was only pleasant when she knew her time alone would be limited. Space and time to herself for an indefinite amount of time with no possibility of interruption was dreary. And lonely.

She wanted to eat her dinner while listening to Alexis's blithe chatter about her classes and her friends and Martha's dramatic, exaggerated stories about theatrical life and Castle's funny stories and teasing rejoinders. She wanted the conversations and the laughter and the affection that flowed so freely between them. She wanted her family, the family life she'd somehow become a part of, back. She wanted Castle back.

He was the center of it all, the beating heart of his family, even if during dinners at the loft, he was often (amazingly enough) rather drowned out when compared to Martha and even Alexis, at times, outnumbered by the women in his life as he liked to complain.

More than that, he was… what? He was her lodestone. When he was around, she felt as if she were a compass that had been somehow reconfigured to make him true north, her awareness and her senses focused on him even if she wasn't looking in his direction or ostensibly paying any attention to him at all.

She missed him. She was a little dismayed and annoyed at herself for missing him so much because it wasn't as if he'd entirely dropped off the face of the planet. She could still contact him. They still talked every day. Throughout the day, even.

They'd been texting back and forth with so much frequency to the point that she was beginning to wonder if she might develop repetitive strain injury from texting him so much with her sending him brief summaries of the cases they'd had while he'd been gone and him responding with the occasional crazy theory—and his theory-texting had given her the only reasons to laugh while at work in the last two weeks. Espo and Ryan had made more than a few teasing comments about how her phone was practically glued to her hand these days and she had glared at them with as much heat as she could muster but had been aware that she was blushing a little—and it wasn't like they were wrong.

And then almost every evening, as long as Castle didn't have some publicity event to go to in whichever city he was in, once she got home from work, one or the other would call and they would talk over Skype. And though Kate didn't particularly want to admit it—probably wouldn't admit it out loud—those calls with Castle were the times she'd been happiest in the past two weeks. She spent most of her days looking forward to her calls with Castle because texting him, as amusing as his texts could be, was simply not the same as being able to see him and hear his voice and his laugh.

But really nothing made up for his physical absence. It was ridiculous since Kate had never been a clingy girlfriend, had been more likely to want space than to want more closeness. She wasn't even sure she liked missing Castle as much as she did but whether she liked it or not, she had to admit that the knowledge that Castle was away, that she couldn't simply go over to the loft and see him, was wearing on her.

It had been more than two weeks since she'd been able to kiss him or touch him in any way.

16 days, 11 hours, and 42 minutes, give or take, since Castle had wrapped his arms around her and kissed her long and thoroughly, kissed her deeply enough that by the time he drew back, she had to blink a few times before the haze in her brain had dissipated, and he'd given her one of his usual smug smiles, kissed her nose teasingly, and then they'd left her apartment together, she to go into the precinct and he to return to the loft to finish packing before heading to the airport.

16 days, 11 hours, and 42 minutes—which was approximately 15 days longer than the amount of time she was discovering she ever wanted to go without being able to kiss Castle.

And if the extent to which she missed him during the day wasn't irritating enough, she hadn't been able to sleep well since he'd been gone. It was stupid, ridiculous really, since it wasn't as if she and Castle had spent every night together in the past couple months. She had spent nights without him after she'd moved into her apartment since as long as Alexis was around, Castle couldn't spend every night out and she'd been fine during those nights.

Of course, it had helped knowing that it was only a matter of hours before she'd see him again—and helped, too, that on a couple of those nights, he had let himself into her apartment late at night long after Alexis would have fallen asleep, using the key she'd given him and she'd been awoken by his sliding into bed beside her. (The first time he had done that, she had startled awake and landed a rather solid punch to his ribs before she'd realized it was him. She winced a little and smiled at the same time as she remembered the way she'd proceeded to make it up to him afterwards so that by the time he had left her bed in the early morning hours, she'd been able to be quite sure that his memories of that night would not involve physical pain—or at least, not physical pain in the area of his ribs since he had choked out that she was killing him at one point during the night.)

But she'd found that sleeping alone while knowing that Castle was hundreds of miles away and there was absolutely no possibility of his either sneaking into her bed (or her sneaking into his, for that matter) or of seeing him first thing in the morning was a very different thing. Her bed had suddenly seemed enormous, a vast, desolate space without him in it. And damn it, when had she gotten to be so dependent on him for something like sleeping? She was used to sleeping alone, had always preferred to sleep alone, even when she'd been in relationships. She refused to believe that less than three months of sharing a bed with Castle most nights could have changed her so much and made it impossible for her to sleep soundly without him. She flatly refused to believe it.

(But she was beginning to think that, whether she believed it or not, it was true.)

It didn't help her denial that the only night she'd managed to sleep really well had been the evening she had stopped off at the loft to water the couple house plants that were usually Alexis's responsibility. She had used that excuse to spend the night in the loft, even if it had been odd being there entirely alone, but she had managed to sleep, soundly at that, on Castle's side of the bed with the scent of him filling her senses.

Castle had not been pleased with Black Pawn for arranging for him to go on a book tour for more than two weeks to help promote Naked Heat, which was getting released in a month, but he'd relented after both Gina and Paula had pointed out to him that a certain number of book signings around the country were a standard part of publicity and they had, at least, scheduled the book tour for while Alexis was still away at camp. He still hadn't been thrilled with the idea and had asked her rather pleadingly (and only half-jokingly) if she couldn't insist that he was far too vital to the work of the NYPD to be spared for more than two weeks. She had laughed and assured him that the homicide division of the 12th Precinct had been around and solved a lot of murders before he'd arrived and she was sure they could manage without him.

He'd pouted and fixed her with one of his puppy-dog looks. "But you'll miss me, Beckett."

She'd smirked at him as she pretended to think about it. "Mm, maybe," she'd teased him. "I think I might enjoy the peace and quiet."

He'd made a face at her. "Don't be mean, Beckett."

She'd laughed again and kissed him lightly. "It's only two weeks, Castle. You'll be back before you know it."

"And who's going to keep you supplied with coffee while I'm away? You without caffeine is a menace to society," he'd quipped.

She had narrowed her eyes at him mock-threateningly. "I'm perfectly capable of getting coffee for myself, Castle. I managed just fine before you came along, you know."

He'd huffed an exaggerated sigh. "I know but would it kill you to let me feel a little bit helpful?"

She'd hid her smile as she told him with a straight face, "You're very helpful, Castle," and then when his face had lit up, she'd added, "You're the class clown who keeps everyone amused."

She'd laughed at his indignant "Hey!" before she'd smoothed away his mock frown by kissing him.

And now, for all her teasing and her vaunted confidence that she would be able to manage just fine without Castle for two weeks, even if she'd expected to miss him a little, she'd rather been hoist by her own petard, unable to so much as sleep comfortably without him, gravitating towards his warmth only to find it wasn't there, as if even in her sleep, her body sought his and woke when it found he wasn't there.

The precinct wasn't the same without him and she knew Espo and Ryan felt Castle's absence too. Whenever she left the precinct to chase down a lead, she found herself expecting Castle to fall into step beside her only to have to mentally shake herself and hope no one else noticed her infinitesimal pause or she'd open her lips to say something like, "You coming, Castle?" and would have to swallow the words back. She didn't know how many times she'd turned to the space beside her to address him with an observation or a quip or theory building or anything only to be reminded that he wasn't there.

Really, the man was everywhere! She couldn't seem to avoid the thought of him, was constantly finding herself orienting towards the space beside her where he always was, only to find herself feeling like a flower without the sun. She hadn't realized just how thoroughly he had woven himself into every corner of the fabric of her life until he'd left and even his frequent text messages were no substitute for him.

It was ridiculous!

Kate huffed in annoyance at herself and almost stalked back out to her kitchen where she dished up the takeout she'd bought on the way home and then settled on the couch to eat. She ate quickly as she usually did when she was eating alone and found her eyes wandering to the full-length bookshelf just visible through the door into the small room she was using as a study/library.

The bookshelf had been a gift from Castle and had accompanied his exaggeratedly ceremonial presentation of the full set of all his books, along with a smattering of Patterson's and Cannell's books and a number of Agatha Christies. She had made a token protest at his buying her the bookshelf; she felt bad enough that she had, in the end, taken him up on his offer of Martha's old furniture and had taken Martha's couch, her dining room set, a nightstand, and a coffee table from among the things in storage. She had been a little reluctant but on asking Martha, Martha had assured her volubly and flamboyantly that she was more than welcome to take anything and everything she wanted to from storage. Thus reassured, Kate had given in, much to Castle's poorly concealed delight. And on giving her the bookshelf, Castle had assumed an exaggeratedly pompous air and pontificated that, as an author, he had a personal and vested interest in ensuring that his books, the fruits of the labor of years, were not stored in boxes or—the horror—stacked on the floor. She had laughed at him but found herself giving in.

The sight of the bookshelf reminded her of the advance author copy of Naked Heat, which Castle had given her just before he'd left. She had already read it, enjoyed it thoroughly (and thanked him for it just as thoroughly), and she felt a small smile hovering over her lips as she thought of the printed dedication: To my best friend and partner, for all the ways you make me smile and amaze me every day.

And on the same page, he had handwritten his own personal message. Kate, all my love, always. Rick.

And Castle would be back tomorrow. She smiled briefly to herself at the thought, one that had been echoing in her mind at various times throughout the day. Tomorrow.

Tonight, Castle had mentioned that Black Pawn had arranged for him to have dinner with some big muckedy-mucks up in Boston, or so Castle had termed them. So he wouldn't be free to call her.

But he would be home tomorrow. Alexis's summer program was ending at the end of the week and a few days after that, Alexis would be flying out to California to spend a week with Meredith. Martha's touring production would be returning to the City in two weeks, just a couple days after Alexis's return from California. And then her family would be whole again. At least, as whole as her family could ever be.

On that thought, her dinner finished, Kate moved into her office and opened up the shutters. Her eyes went at once and first, as always, to the picture of her mother's body, and then the post-it summarizing the bare facts of her murder. Kate felt a slight shudder go through her. I won't let you down again, Mom.

She was fine, she told herself. She wasn't going down the rabbit hole again. She was in control. She didn't spend all her spare time obsessing over her mother's case. It wasn't like before.

She had only just started putting together the makeshift murder board on the shutters and the window in her office. She had spent a couple evenings on it since she had first decided to seriously look into her mom's case again.

Her eyes went over the other pictures, the post-its with the simple facts of the other murders, which she'd found from the quick copies she'd made of their files. The three other victims. Diane Cavanaugh. Scott Murray. Jennifer Stewart.

And Johanna Beckett.

Murdered on someone's order by Dick Coonan.

She remembered again what Dick Coonan had said. Forget it. You'll never touch him.

Kate set her jaw. Whoever had ordered her mom to be killed had never met Detective Kate Beckett. And she had promised herself that she would bring justice to her mother's killer and she would not, could not, let her mom down again.

Kate's train of thought was abruptly interrupted at the sound of a knock on her door.

She frowned a little. She had no idea who that could be.

Purely out of habit—and an excess of caution—she quickly retreated into her bedroom to grab her gun and placed it on the small table just inside the inner door where it would be in easy reach. That done, she opened the door.

And stared.

"Cas—Castle?!"

Castle gave her a lopsided little grin. "Surprise."

She attempted to retrieve her jaw from where it was nearly scraping the floor. "I thought—what are you—you're supposed to be in Boston."

He shrugged a little. "The dinner sounded like it would be a bore so I claimed to be exhausted from all the travel and cancelled and then hopped on the next flight back to surprise you." He paused. "You going to let me in, Beckett?"

She didn't pause even to smile before she reached out, grabbed the lapels of his jacket, and pulled.

He let out a surprised laugh, releasing the handle of his rolling suitcase the moment it was inside, freeing up his hands. "Does this mean you missed me, Beckett?"

She smirked at him. "Shut up and kiss me, Castle."

He did.

Kate closed her eyes, wrapped her arms around him, and gave herself up to his kiss.

And somewhere inside her, she felt as if a little part of her that had been feeling off-balance settled back into place.

Castle. Castle was back. And for that moment, all was right in her world.

~To be continued…~