Disclaimer: Don't own

A/N: Hi again! I honestly didn't think I'd write another fanfic after The Art of Living ... but alas. These things do suck you in. I'd like to throw a little hope out there. All the gloomy doomsday-naysaying in fanfic is harshing my mellow, and the foreshadowing on actual eps is worrying me. So I wanted to write something that focuses on the positive aspects of our fave couple's relationship, and the fact that they are generally, you know, decent folks who genuinely respect and look out for each other.

Takes place in current season four. This one took a spin in the fluff-o-matic 3000.

Four Saturdays 1/5

The Setup

Beckett was seated at her desk, immersed in finishing off paperwork for the case she and her team had just wrapped up, when Castle vaulted himself into his usual seat by her desk.

"I know what I want for my birthday!" Castle declared, his excitement almost knocking her over.

"Of course you do," she replied, trying studiously not to pay any attention to him. If she let Castle distract her she would never get her work done, and right now she was intent on finishing up the paperwork for their most recent case: if she kept up this pace, she could be home in an hour and a half, and immersed deep in a hot bath within two hours. She'd been at work since 4AM, and kept awake all last night by an inconsistency in the case she was currently tying up. Now that it was about wrapped up, she needed to retreat, to recoup. What she wouldn't do for a hot bath, she sighed with longing at the mere thought of being blanketed in that warm cocoon, bubbles fizzling lightly against her skin...

"My birthday is in a few weeks," he elaborated, leaning forward to get into her field of vision and interrupting her fantasy, "and I know what gift I want from you. By my calculations," he informed her with slight recrimination, "you owe me four years worth of backlogged birthday gifts."

"I do not owe you four years worth of birthday gifts," she said without looking up from the form she was filling out.

"Let's do the math together, shall we? Year one-"

"I have paperwork to finish, Castle," she pointed out, not unkindly. "I want to get home at a reasonable hour tonight."

"Year one," he continued, completely ignoring her, "I got you an advance copy of Storm Falling."

"You did not get me that for my birthday!" she exclaimed, caught somewhere between indignation and laughter. She pointed a recriminating finger at his nose. "You gave me the advanced copy to trick me into letting my guard down so you could steal files off my desk, you sneak."

"You say tomayto, I say tomahto."

"You are unbelievable," she accused with a smile. First he kept score of who saved whose life, and now this.

"If you mean unbelievably hurt that you have yet to get me a birthday gift, then yes, it is unbelievable." He was, much to her chagrin - and her amusement - completely serious. "Year two, I gave you an all-inclusive three day retreat at Chez Castle."

She frowned in confusion. "A three-day retreat?" Surely she would remember that...

"I let you stay at my loft after your apartment blew up," he clarified.

"How can you possibly count that," she protested. "You made Montgomery force me into staying at your loft after a serial killer decided I was really Nikki Heat and blew up my home."

"Can I help it if my writing is so realistic that people can't tell it apart from fiction?"

"You have got to be kidding me."

"Year three, I helped set up the Johanna Beckett Memorial Fund."

She had no answer to that.

He grinned smugly in the comfort of his one little victory.

It was hardly fair, she thought mutinously. There was nothing she could think of doing that could show just how much the fund he set up in honour of her mother meant to her. It had been an overwhelmingly sweet gesture, one that still warmed her through to the tips of her fingers. She could hardly point out that he hadn't done it anywhere near her birthday. And she could definitely not refuse him his intrusive birthday request after what he'd done for her mother.

"You can level that scary look at me all you want," he said, eyes shining with amusement. "I'm not above playing dirty to get a birthday gift from you this year. Four years, Beckett, and you have not honoured the day I was brought into this world."

"How ever have you survived," she said wryly.

"It is my cross to bear," he acknowledged with more than a touch of melodrama. "So," he said happily, "you owe me four years worth of gifts."

"That's only three you've listed," she reminded him. "None of which were actually birthday gifts, might I add."

"This year - number four - I gave you the gift of seeing me dressed up as Elvis."

"Gave me the gift?" she repeated, unable to stop herself from picking on him. "More like scarred my retinas."

"Has anyone ever told you that you're not very good at accepting presents?"

Kate tried really hard not to roll her eyes. Her bath was becoming a more and more distant dream. He was a dog with a bone when he got like this.

"And there's that scary look again," he said, not in the least bit concerned, let alone afraid.

Clearly, she used it too much on him if he was immune to it.

"So for my birthday..." he paused for dramatic effect, which only served to deepen Kate's worry, "...I want four of your Saturdays."

"You want what now?"

"I get to spend four Saturdays with you," he explained.

"What?" She stared at him. "Why?"

He looked at her wearing that I-have-a-hidden-agenda-I-don't-want-you-to-know-about expression on his face.

"No," she said. And then went back to her work.

"You're just going to say no?" he protested, sitting up straight in his chair. "Just like that?"

She flicked a knowing glance at him. "When you're ready to tell me what this is really about, I'll listen."

He studied her for a moment before nodding reluctantly, looking boyish and appealing in the buttery light cast by her desk-lamp.

"I shadow you at work all the time," he said, "and it's made Nikki Heat my most popular character. I know the ins and outs of Detective Kate Beckett, but I don't know what you do in your off time. What do you do when you have a Saturday to yourself? I've known you for four years and I don't know. I don't have much of a clue."

"So this is about muse duties?" she asked, not exactly disappointed. Really, she wasn't. It was just that she'd expected … something else. Maybe. She rallied: "And it's called a private life, Castle. I'm pretty sure we've had this talk before: we established clear boundaries when we first started this unorthodox partnership." She cherished boundaries exactly as much as Castle trampled all over them. She also wasn't quite ready to let Castle barge completely into her life and occupy every nook and cranny. Well, more than he already had. She needed time.

"An unorthodox partnership that I like to think has evolved into one of my most cherished friendships." He smiled warmly at her.

Point for Castle, Kate conceded, trying not to smile. And damn him for being so sweet.

She floundered for an excuse.

"You've already written three Nikki Heat books. I think you've got the character down."

"As an aficionado of the Derrick Storm series, you should know that-"

"I would hardly call myself an aficionado," she interrupted defensively.

"Please," he dismissed her protest with a wave of his hand. "You subscribe to my fansite, iHeartCastle82."

"Oh jeez, Castle," this time she didn't bother withholding an eye-roll, "that is not a handle I would ever be caught dead using."

"One day, I will find out what your username is," he vowed.

She could assure him with a hundred percent certainty that he most certainly would never find that out. She held her silence, eyebrow raised in challenge.

They engaged in a staring contest that lasted about three seconds, with Castle - as was usually the case - throwing in the towel. She very maturely hid her smug surge of satisfaction at winning this round.

"As I was saying," he continued, when he realized he wouldn't be getting any answers to that line of inquiry today, "as a Derrick Storm expert, you know that to create a successful long-running, character-based series, an author has to develop a meaningful and evolving character arc for the protagonist. In this case: Nikki Heat. Readers know what drives her, they know what holds her back, but now they need to know that she is more than the sum of those parts of her. They need depth, they need more than the job and the back-story. I just … would like to explore Nikki's character from different angles. She keeps telling me to focus on her kick-ass cop skills, but I know there's more to her."

The subtext was hitting awfully close to home. She wondered if he realized. For a man who had such a masterful grasp of literary devices, she thought that he sometimes lived in the stories and forgot about the opportunities reality afforded.

"Already running out of material, Castle?" she settled for teasing him.

"You know better than that." His reply was nothing if not sincere.

"Castle," she started to protest - he'd hardly needed her help in developing his character in the past -, but stopped when she saw how his eyes remained expectantly fixed on hers. She could see how badly he wanted this. It written all over his face.

"It's for my birthday, Kate," he appealed to her softer side, much to her dismay. Somewhere along the road, she'd stopped being able to say no when Castle asked. "Please? For me?"

She sighed, felt herself giving in to his pleas. How bad could it be? They'd spend a day together. Castle had been good, for the most part, about giving her the space she needed after the summer. It was not as though he was asking her out on a date, right? And for all he'd done for her, this could be her way of giving him something back. She purposefully shoved the memory of his whispered confession from months ago out of her head. Now was not the time to dwell on the guilt and pain and anger and raw hurt she still felt at remembering that afternoon, and the days preceding it.

"One Saturday," she offered.

"Four entire weekends," he countered.

"That is not how you bargain, Castle," she scolded him.

"That is exactly how I bargain," he informed her. "You made a completely unreasonable counter-offer, so you left me no choice but to do the same."

She gave him a glare that held no strength, only humour.

"Two Saturdays," she said.

"Four Saturdays. It's my birthday, Beckett. How can you say no to a birthday wish?"

"Ugh," she groused, caving in to his emotional blackmail. "I can't believe I'm doing this."

"And they have to be Saturdays when you are not working or on call." He held out a hand. "Shake on it."

"What are we, twelve?"

He arched an eyebrow, the way he usually did when she was being stubbornly recalcitrant.

"Fine," she conceded and took his hand in hers, giving it a firm shake. Her heart worked double time to beat out of her chest. Why that was, she cared not to contemplate. "Saturdays when I'm not working."

"Or on call," he added pointedly.

"Or on call," she repeated.

Castle was grinning widely at her, as gleeful as she'd ever seen him.

"Best. Birthday. Gift. Ever." His eyes were quite literally sparkling, bursting with happiness.

She couldn't help but smile at his infectious enthusiasm. And optimism. Even though the enthusiasm worried her. And the optimism baffled her. Then again, Castle's ability to take immense pleasure in the smallest of things was one of the things she found most fascinating and, to tell the truth, attractive about him.

"How do you know these won't be miserable Saturdays for your character development?" she couldn't help but ask. 'What if I spend my days off doing laundry?"

"Then I'll offer to fold your intimates," he wagged his eyebrows. "It'd still be the best birthday gift ever."

"How very gallant of you," she injected a heavy dose of sarcasm in her reply.

"They won't be miserable Sundays. I like spending time with you," he said with certainty, and perhaps more sincerity than she was ready for. "More importantly," he continued blithely, "for all your bluster, Katherine Beckett, you forget how well I know you. You're too pure of heart to make me suffer through menial chores."

"Flattery will get you nowhere," she lifted an eyebrow at his transparency.

"That wasn't flattery," he corrected with a grin, "that was charm."

She laughed. "Go home, Castle, and let me finish my paperwork." She waved him off with her pen, and bent her head down in an attempt to reclaim the focus Castle had interrupted.

"Will do." He stood up from his chair. "And, Kate?"

"Hm?" she replied, not looking up from the file in front of her.

"Thank you. Really."

She looked up at him, pulled by the warmth in his tone.

"Happy birthday, Castle," she said, wondering whether anything she could do would live up the to expectations he seemed to have set.

"It definitely will be," he grinned lightly, his eyes holding the tender affection that once upon a time unsettled her. Now, it centered her. "Until tomorrow." He turned and headed for the elevators.

She watched him go, not returning to the files in front of her until the elevator doors shut behind him.

"You're in an awfully good mood," Martha commented from the couch the minute he walked into his loft.

"Today was a good day," he replied with a wide smile.

"An especially gruesome murder?" she asked, browsing a catalogue with a glass of wine in hand.

"Nope." He stopped himself when he recalled the case they actually had worked on today. "Well, yes actually, there was that, too."

At that, she set aside her magazine completely and focused on him. She loved gossip more than she did catalogue-shopping.

"Then what has you smiling like the cat that ate the canary?"

"Beckett gave me my birthday gift today," he grinned.

"Really?" His mother perked with excitement. "What did she get you?"

"Four of her Saturdays," he said as he took a seat next to her on the couch.

Confusion met his reply.

"She offered to spend four Saturdays with me," he elaborated. "Four of her days off."

"That is awfully generous of her," Martha said, not without a little wonder. His mother was not unfamiliar with Beckett's wall. "This is a good thing, right?"

"I may have ... begged a little," he said, thinking that he perhaps ought to feel a little bad about that. But he didn't. Not even in the least. Even if he'd exploited her exhaustion over the case they'd been working on the past couple of days to catch her while she was weakest. After all, what was the point of knowing someone so well if you didn't use that knowledge for their own good? "But it's the thought that counts, right?" he defended at his mother's disbelieving stare.

"Well, Darling," she said after a moment's thought, "no one really cares how the sausage is made, after all."

They shared a doubtful look.

"This is a good thing," he said decisively, breaking their stalemate.

"Let's go with that," Martha agreed. She raised her glass in a silent toast.

"It is a good thing," he repeated in an attempt to convince them both. "99% of the time I spend in Beckett's company is spent solving murders - not that I don't enjoy that aspect of our relationship - but this way I can spend time with her without a stranger's death hanging over us."

"Or her mother's?" Martha suggested.

Castle sighed. "That, too," he agreed. "She holds onto it so tightly. I just … want her to let it go. "

"It has made her who she is, Richard."

"I know," he replied. "I know, but there is so much more to her. I can see glimpses of it." He cast an uncertain glance at his mother. "Outside of work, where she's not Det. Beckett, maybe I'll be able to get a better look at her without the specter hanging over her."

"And set your mind at ease. You still blame yourself for what happened," she stated, more than asked. He could hear her disapproval.

He said nothing. They both knew the answer.

"Richard, it wasn't your fault-"

"Regardless of whether or not it was my fault" he interjected, "I should be helping her get closure. Not re-opening old wounds."

"This is not your battle," she said gently.

"I'm on her team, Mother. I've made it my battle."

"I think you've helped her get closure more than you give yourself credit for," she gave him a pointed look, the scolding kind only a parent was capable of.

He wasn't convinced. Sometimes, when he closed his eyes, he could still see the hurt in her eyes when she'd looked at him the night Montgomery was killed. He could still hear the crack in her voice when she'd told him, months later, that she had no one left.

Martha sighed, and he knew she was going to let it go. For the moment.

"Four Saturdays, huh?" she said lightly, attempting to alleviate the sombre mood. "Try not to drive the poor girl crazy."

"But mother," he teased, "it's what I do best."