A/N: Yet again, I succumbed to a short video posted on Twitter by Sandraxf. It showed the scene from 3x21: "Dead Pool" where Beckett says "Always" for the first time. The way they look at one another tickled my brain into producing this one-shot.

One-Writer Girl

The case is closed but they're still dawdling in the bullpen, neither of them ready to say goodnight and go home. Castle's hands are stuffed deep inside his pockets as he stands before the murder board pontificating on the end of the case.

"You know, it is ironic," he says. "The one man Zack thought he could trust, his mentor, turned out to be his killer."

Kate brightens at his comment and her eyes sparkle with that clever look that he loves, right before she takes the conversation in a surprising direction. "Yeah, speaking of mentors. I heard that you guys were pretty hard on Conrad last night."

She's caught him off-guard and he pulls a face to match his flat denial. "Hard on him? No, no. It was just a little friendly hazing."

Beckett isn't buying it. "To hear him describe it, it sounds like someone was trying to teach him a lesson." She leans in close so that her partner knows he will not be able to wriggle out of answering this time.

Castle tries and fails to look mystified and innocent. "What? Why would I want to do that?" he asks, rearing back a little to put some space between himself and his all-seeing all-knowing detective partner.

If he was surprised before, he's shocked by the next thing Kate says because they don't, as a rule, do honesty. Especially when it comes to "them."

"Because you didn't want him to spend time with me," Kate says. Her answer is astonishing for its frankness as well as being on-the-money accurate, and they both know it.

Still, Castle fluffs a last-ditch refutation. "That is completely⏤"

"True?" Beckett says emphatically.

At this point, Castle folds like a bad poker player. His voice flattens, descending a few octaves from his high-pitched rebuttal. "Yes. Fine. It's true. I'm jealous. There, I said it. I⏤ I want you all to myself, and to have you spending time with another writer, that upsets me, and if⏤ If that makes me petty, so be it. Guilty as charged." He finishes with a flourish, his chin tilted up in defiance against the comeback or admonishment he anticipates will immediately follow from her.

Yet again, Beckett surprises him. She flashes a gentle, almost bashful smile. "Actually, I kind of think it's sweet."

"You do?"

She nods and smiles more, which is always good news. "I do. And that's why you don't have to worry about me hanging around with Conrad anymore. From now on, I'm a one-writer girl."

They look at one another for one long, seemingly endless moment, their faces open with gazes so direct that it's as if all the flaking, peeling layers that had built up like a barrier between them have simply been stripped away. Kate hangs on, willing herself to look into his eyes for as long as she has the courage to. In doing so she finds that looking at Castle and letting him see her heart isn't half as scary as she thought it would be. He has such beautiful eyes and such a beautiful heart.

"Thank you," he says, his words and tone full of sincerity.

"Always," she replies immediately, hanging on just a second longer before she nods, her lips pressed into a nervous line, and looks away.

Just as she's about to turn back to her desk and sit down, Castle says, "Always?" to which Kate hums an affirmative, "Mm."

There's a brief pause before he takes a courage-gathering breath of his own and asks, "Beckett, would you like to have a drink with me?"

This surprises her. It sounds more formal than their infrequent, post-case, spur of the moment decisions to grab a beer, which is usually done in the company of the boys in any case.

"Tonight?" she says and a frisson of excitement races down her spine from out of nowhere. Because she might sound like she's asking a question, but she might also be making a suggestion of her own.

"How about now?" Castle says.

It's already after seven. Kate grins. "Now is kind of tonight."

"Exactly," he agrees, grinning with her. "So…would you?"

She hesitates for just a second more before answering, "Yes. Yes, I would like that."

When Kate turns away to shut down her computer, she misses the look of sheer delight on Castle's face. Well, she almost misses it. She grabs her purse and pushes her chair neatly beneath her desk, turning back to find that he's still smiling at her with eyes that radiate a pure kind of joy and excitement as he patiently waits for her. She smiles back, equally joyful and newly confident that she's doing the right thing. "Okay. Let's go," she says.

They head for the Old Haunt. It's a walkable distance from the precinct, it's not out of their comfort zone, and Castle owns it, so they can drink for "free" all night and have their pick of tables. At least, that is the theory. When they get inside, the place is surprisingly full.

"Business is good," Kate says, raising her voice above the burst of noise as she looks around, taking in the scene. "How about we sit at the bar?" She's already scoping out two vacant stools and weaving through the crowd before Castle can stop her. He's disappointed. He wanted them to sit in a booth together, but all the booths are taken. So he weaves through the crowd after her, acutely aware of the stares she's drawing from both patrons and staff, men and women alike.

As she rises up onto her bar stool in her cool jeans and leather jacket, Castle watches how at ease she is in this raucous, crowded environment, how self-assured, and he might stare a little himself at her legs as she arranges herself on the high stool. He settles down facing her and is about to ask what she'd like to drink when he turns to find her shaking hands with one of his barmen and ordering for both of them.

He laughs and finds the tension in his chest easing a little. This is a last-minute, unplanned thing for them, something they almost never do: go out drinking together, alone. He wants tonight to mean more than it probably means to her; he badly wants it to be the start of something. He needs to get ahold of himself.

All he can think about is her telling him, not half an hour ago, that from now on she's a one-writer girl. He wants that to mean they're going steady or something equally innocent and juvenile but committed, or not so innocent when he really thinks about it. He doesn't want to give this woman a promise ring; he wants to promise her everything with the biggest diamond he can afford. He wants her promise of "always" to mean exactly that.

Castle startles when the object of all this fantasizing slides a glass of merlot his way. She smiles at him with a look of intention that feels new and her eyes crinkle at the sides. There's so much warmth there and it's entirely directed at him. God, he is so in love with her.

Kate waits for him to lift his glass then she touches the rim with her own in a casual toast. "Cin cin!" she says, smiling more broadly. She looks so beautiful.

"Cin cin!" he repeats, struck once again by how much more there is to Kate Beckett than New York cop. He wants to show her the world, to take her to places she's never been and have her take him places he's never seen. He wants to lie back on sun-warmed sand and listen to her speak in languages he'd have no hope of mastering if he studied for a thousand years.

Castle has slipped so completely into his imagination that when she touches his knee he almost levitates in shock. "Rick?" Kate leaves her fingers resting on his leg to ground him, her head tipped slightly to the side in concern. "Are you okay? Where'd you go?"

Now she's calling him by his first name and he thinks he might be having a heart attack. But what a way to go. They're almost there. He can feel it.

When he nods that he's fine and forces a nervous smile, she squeezes his knee softly and removes her hand. He thinks she catches the flash of disappointment on his face before he can cover it up. He decides that's not necessarily a bad thing. It means he doesn't have to whine out loud for her to know that he wants her touching him. How badly he wants her touching him. He imagines he can still feel the imprint of her fingertips long after they are gone.

A moment later, Kate is staring across the room, lost in her own thoughts, Castle assumes. But then she jumps down off her stool and casually tugs on the front of his jacket. "Bring the drinks. A booth just opened up." And with that she's off, cutting through the throng again, on a mission to secure them a table. It seems they might be of the same mind tonight after all.

When Castle spots another couple making a beeline for the same spot, he catches the eye of one of his bar staff and the young guy steps in to save the booth for them until Kate can get there. She turns in triumph to give Castle a big smile and a thumbs-up sign to signal that he should follow, bringing their glasses of wine.

Castle leans over the bar. "Keep 'em coming," he tells the barman.

"Feeling thirsty tonight, Mister C?" the barman casually asks as he rinses out a drip tray.

Castle pauses for half a second before shaking his head. He raps his knuckles on the bar. "Feeling lucky, Frank. Feeling lucky," he says before he scoops up the glasses and turns to join his partner.

"Must be the weather," Frank calls after him, giving Castle a wink. "Spring is in the air."

"What was that all about?" Kate says when Castle places her drink in front of her with a theatrical flourish.

He frowns and glances back over his shoulder. "Frank?" he says, playing for time. "Just…shooting the breeze about the weather."

Kate smiles around the rip of her wine glass before taking a healthy sip. "The weather? Castle, how long have I known you? I don't think I've ever heard you talk about the weather."

He grapples around for an answer. "That's…that's because you and I always have so many other scintillating things to discuss."

"Scintillating?" she says as if tasting the word. Her eyebrow twitches in amusement when she deadpans, "Like murder?"

"We talk about more than murder. A lot more."

"A lot more?" she repeats like she's examining his theory for holes. "And…what else? What else do we talk about, Castle?"

Now there's an opening if ever he heard one.

Castle takes a sip of wine then clears his throat. He places the glass down carefully. "There is something I'd like us to talk about."

Kate feels her stomach flip then begin to flutter with a sudden onset of nerves. "Okay. Sounds vaguely…ominous." She mirrors him, taking a sip of wine, too. Dutch courage. "Should I be worried? You're not sick or something?" She laughs nervously. "Didn't get married in Vegas when I wasn't looking or…or get yourself arrested? Again," they both say together through a light veil of laughter. Both seem equally nervous now.

"Uh, no. None of the above. Though it's good to know that you care."

Kate shifts in her seat. In the past, she'd have tossed out some humorous, biting put-down, a quip like "What makes you think I care?" But now isn't then; they've moved on a lot from the early days. So she says, "I care. Of course, I care," with as steady a voice as she can muster because she cares about him deeply, and when she thinks about the scenarios she just conjured off the top of her head, they affect her. She wants him to live a long and healthy life. She wants him marrying no one but…well, maybe her one-day. Oh, God, she can't believe she's even thinking like that. And if anyone is slapping cuffs on this man, it'll be Kate Beckett and no one else.

"Are you blushing?" Castle asks. He leans in a little closer to check her face in the miserly halo of light being doled out by the pendant lamp that hovers above their table. "Detective Beckett, are you blushing?"

Kate furrows her brow and she fights an embarrassed smile that forces her to turn her head away. "Blushing? No." She nudges him, hard, eventually shoving his elbow off the table when he continues to stare at her. This playful gesture only succeeds in drawing them even closer to one another.

Castle chuckles and leans back against the booth, seemingly satisfied with his efforts to embarrass her. He's relaxed and happy. So happy that he stretches his arm out behind her along the back of the booth. They're sitting quite close to one another. He probably slid an extra inch or two further into the booth than he normally would when he settled in beside her. He wouldn't dare get so close if the boys were here. Much as he loves Ryan and Esposito, he's glad they took a field trip to Rikers with Conrad allowing him and Kate to go out alone for once. He leans further back against the green leather banquette and they both sip their wine, their movements like a water ballet, coordinated down to a fraction of a second. If they can do this so gracefully and in sync with one another just imagine how well they'd dance together…or make love, he thinks to himself.

Just as he's conjuring a more detailed vision of this last scenario, Kate interrupts his fantasy.

"So…out with it. What did you want to talk about?" she says. She's dancing on a knife-edge today and she likes it. The wine is loosening her limbs and her tongue. Her body is warm, almost liquid, and she can feel the heat radiating from her partner's muscular frame as he sits close to her. Tonight feels different somehow. After how whiny and jealous he was about Alex Conrad, she's more certain than ever how Castle feels about her. He's possessive, proprietary, and she made him so happy when she told him she's a⏤

"One-writer girl," Castle says, slapping his palm down on the table. "I'd like to hear more about that." He gives her a brave and probing look. But there's humor in there, too, which she knows is because he expects her to shut the conversation down or take it in another direction entirely. But she's not backing down tonight. They feel like equals. They feel as if they've somehow staked their claim and if not exactly that, they've shown their hand as regards how they feel about each other, or might feel one day soon. "What exactly does it entail? For me," he adds with a smirk, pushing more than he usually would. "Sounds like there should be perks. Having you be my one-writer girl."

"What do you want to know?" Kate says, casually sipping her wine to slow her pounding heart, though the luxurious, velvety merlot is sadly having the opposite effect.

Castle shifts in his seat in surprise, leaning in as he prepares to take full advantage of the free pass she appears to be giving him. In his enthusiasm to get down to it, the seat of his pants skids against the leather booth which has been worn to an over-healthy shine by years of use. This sends his knee colliding with Kate's thigh. He reaches out immediately and touches her. It's an automatic apology, a soothing gesture, not at all premeditated. "Sorry," he says. "I didn't mean…"

Kate shocks him again when she pats his arm and laughs. "Relax, Castle. It's fine. You're allowed to touch me. We're not at the precinct now."

The startled look on Kate's face tells him that she maybe didn't think the last couple of sentences all the way through. She frowns to herself and adds, "Sorry, I didn't…"

Castle laughs softly. "It's okay. I know what you meant. I'm not about to molest you just because we're in a bar together. After hours. No case. Just hanging out like…"

Kate is watching him closely. Her lower lip is drawn between her teeth. She releases it when he notices her watching him and his words dry up. "Like we're on a date?" she offers quietly. The faintest blush climbs her neck and a smile flirts with the corners of her mouth.

"A date?" Castle shakes his head, deadly serious all of a sudden. "No. No. This isn't that."

Her eyebrows rise in interest and she rests her chin on her hand. "It's not?"

Castle goes still. "Unless⏤ Did you want it to be?"

"Well,…you did kind of ask me out. So I just…"

His eyes pop wide and he leans towards her. "You assumed we were going on a…that this was a date?"

Kate chuckles. "Castle, you can't be surprised. You asked me out and I said yes." She turns to pick up her wine glass. "But if I got the wrong idea…"

"No!" he practically yells. "I like your idea. It's a great idea."

She laughs quietly. "Okay. Then good. We're on a date. This is a date."

Silence settles across their corner of the Old Haunt for several moments. They're insulated inside a private little bubble of their own making while the bar's patrons carry on their Friday-night carousing.

"How did you know? That this was the time…that now was the right time for this?" Castle finally asks.

Kate angles her whole body towards him. "One-writer girl isn't enough of a commitment for you?" She smirks a little, cool and calm where he is rudderless and anxious, over-thinking everything. To hear Kate explain, it seems so simple. "I said always, Castle, and I meant it. Always is…" She shrugs. "It's our thing but it's really your thing."

"Until today."

She nods. "Until today."

"Why now?"

"I saw how crazy it made you when I was spending time outside of work with Conrad." She holds up her hand before he can interrupt. "Though that's not why I did it, to be clear."

"So you took pity on me?"

She shakes her head. "No. Not pity. Never pity. No, because that's how I feel, too. When you spend time with other women. I figured that had to mean something, right? If we're both jealous of other people." She presses her lips together before she says, "You're my people, Rick. It just felt like the right time to tell you that."

Castle is stunned by her confession. "I...I had no idea. That you were jealous? You?" He shakes his head. "You never...you'd never make a misstep like that. You're not capable."

Kate laughs. "Castle, I'm human. Not some robot and certainly no saint. But misstep?" Kate says.

"Emotional. Toxic. Ugly," he elaborates.

Kate's eyebrows shoot up at this on-the-nose description of jealousy. She knows he's not criticizing her since they've both admitted to their guilt in this department. Jealousy is, granted, most often a destructive, pointless emotion, except that this time it has pointed them towards one another.

He cocks his head to the side, still disbelieving what she's just shared. "Jealous? Really?" When Kate nods, he smiles at her and his eyes take on a glow of amazement, a kind of youthful wonder. "You're my people, too, KB," he adds, softly.

They hold hands under the table the rest of the night, fingers flirting as they watch the crowd in the bar go about their Friday night mayhem from their quiet, tranquil little booth. As first dates go, it's low key, but somehow fitting. Castle's skin tingles where they touch, each new caress slowly setting his body alight. The fire dancing in Kate's eyes tells him that she feels it, too.

Just before midnight, Castle sees her to the front door of her apartment building. While a taxi idles at the curb, Kate drags him in for a long, slow kiss, tugging him to her by the lapels of his coat as they shelter from a surprise rain shower beneath the forest-green awning.

"Can I see you again?" she asks with laughter in her eyes.

"Try and stop me," Castle tells her before they kiss for a second time to the sound of the cabbie honking his horn and the summer raindrops drumming their fingers on the shelter above their heads. Where they are slow and languid, utterly lost in one another, the world around them feels loud and riven with impatience. They take their time with one another, lazily kissing and caressing, letting the world stay on the outside just a little while longer.

Someday they will tell their grandchildren about the Old Haunt and the night in that famous bar where their family story began. But for now, they will enjoy the miracle of finding one another, and the novelty of learning to write that family story from scratch, starting with a goodnight text.

RC: I've just been on my last first date and I couldn't be happier. Sleep well, detective. x

KB: Me, too. Looking forward to a host of firsts and lasts with you. Until tomorrow, Castle. Your OWG xxx

The End

A/N: That was my 100th Castle story. I'm mentally popping a Champagne cork. I hope you'll celebrate with me. Without readers, I would just be muttering into the ether like a crazy person. Thank you for being such a good, loyal audience. Belated Happy Easter. Liv x