The first time happens after their second case together, the one with the murdered nanny.

After going back to the precinct to file her preliminary report, Beckett bids the boys goodnight and escapes. She needs a drink after staring down that knife. She ends up at a bar about fifteen minutes' walk away: far enough to not be a cop bar, and it's just a hair more upscale than most cops prefer anyway.

She doesn't go there particularly often, but the bartender is good. He remembers what she drinks and has her glass filled and ready by the time she gets from the door to the bar. Vodka, with a twist of lime.

She's wearing the fake wedding ring that she keeps at the bottom of her purse. It usually works to deter most, though not all, of the desperate men prowling for booty calls at this not-very-late hour.

She's halfway through her drink when he enters. Goddamn it. Castle. He must have followed her.

She is so not in the mood for him right now, and it's not fair. She's off the clock; she shouldn't have to deal with him. She decides to shut him down. To hell with the mayor. She doesn't have to be polite after hours.

"Mind if I join you?" he asks, and she sees the bartender watching, alert for signs of trouble. Of course she can handle herself, but it's nice to know the guy has her back.

"Suit yourself," she grumbles.

And then Castle surprises her.

"Rick," he says, holding out his hand. She blinks, wondering what the hell this is about.

"Kate," she finds herself replying, shaking his hand. It seems absurd, but he smiles, a bland nice-to-meet-you smile.

"You from around here? I'm just in for the sales conference over at the Hyatt," he says with an easy confidence. He nods at the bartender, giving the universal sign for I'll have what she's having. "Flight back home first thing in the morning," he adds. "Denver."

"Denver?" Somewhat to her surprise, she's playing along. "What a coincidence. That's where my husband ran off to when I filed for divorce." I'm more of a one and done type, she remembers telling him earlier. But that was Beckett, and now, apparently, she's just Kate: a whole different woman.

"You don't say," grins Castle - no, Rick. "Guess his loss is my gain."

"Mm." She sips her drink and watches him taste his. What is this game they're playing? She isn't sure, but there's a warm tingle gathering in the pit of her stomach, and it's not just from the alcohol.

"So," he goes on, lifting his eyebrows in appreciation of the vodka, "have you lived in the city your whole life?" She tenses at the question, wondering if this is just another weird ploy to find out more about her for his damn book - but he isn't finished. "Been here a few times for business," he adds, "but I've never managed to see much of it."

"I grew up here, yes," she gives him a little grudgingly. "Went away for college, came back." She sips her drink, watches him watching her mouth. "So," she adds slowly, "no time for sightseeing in the travel schedule?"

"Nope," he says regretfully. "I've mostly just seen the insides of convention centers and hotel rooms."

Ah. That's her cue, and she doesn't have to take it. She shot him down once before, just after their first case last week; she could do it again.

But something about this little game he has initiated is intriguing her. And, let's face it, she isn't nearly as immune to him as she's been pretending.

"Seen some nice hotel rooms, though, I hope," she murmurs, crossing her legs very deliberately. She keeps her eyes on his face and sees him react to the move, his eyes flashing briefly, but he stays cool.

"Oh, well, you know," he shrugs. "Seen one, seen 'em all. This Hyatt does have pretty comfortable beds, though." He says it without the leer he might normally use; he's in character, and Rick-the-salesman-from-Denver doesn't leer, apparently, not even for comic effect. He does put a little extra emphasis on the words, holding his gaze on her so she can't mistake his meaning.

The bartender has refilled her glass and she takes another sip, then another, watching Castle. He keeps his bland smile in place.

At last she downs the final dregs of her second vodka and says, "Comfortable beds, uh?"

It's the opening he's been waiting for, and he takes it without hesitation. "Come and see for yourself, if you'd like." Now he grins again, slow and sexy. She hasn't appreciated that grin at the precinct the past few days, but here, now, it feels different. She's not Detective Beckett here, nor, it seems, is he Writer Castle. They're just Kate and Rick. They could be anyone.

"The Hyatt, you said?" she husks, and he nods, his eyes darkening.

"It's right around the corner."

It is. And somehow, after a brief walk and a brief stop he makes at the front desk, and then an even briefer elevator ride, they're in a hotel room. Beckett isn't even quite sure how that happened. Rick-from-Denver chatted about skiing almost the whole time. Kate-the-businesswoman of unspecified type answers that she used to love skiing, but just never seems to find the time for it these days.

But now they're in the room, the door is closed, and she's dropping her coat and purse on a chair, thinking, what next?

"So…" He comes over, crowding into her personal space, but not actually touching her. The heat radiating off his body makes her muscles tense up, not unpleasantly. And then he is touching her; lifts her hand, rubs his finger over her ring. She shivers a little. "Husband out of the picture, huh?" he says, low, and she isn't sure whether he's confirming her story or still playing the game.

"Yeah," she answers, her voice not nearly as steady as it could be. "And you, heading back to Denver in the morning."

"Right," he agrees. He drops her hand and moves around behind her, the solid wall of his body brushing her back. His lips skim along her neck. His hands are on her hips, but lightly, and she understands that this is her out; this is the moment when she can take a single step forward and end this. They could laugh about it as a silly game they played on the spur of the moment, and nothing would change.

She doesn't step forward.

She tilts her head to the side, just a little, exposing more of her neck; she presses her ass back against him. His breath puffs out hot across her skin and his fingers tighten on her hips, gripping her with authority now. His mouth opens on her neck and she gasps at the touch of his tongue, the wet slide of his lips down toward the juncture of her shoulder.

But her turtleneck gets in the way and he grunts in frustration, his hands moving up to snag the bottom hem of the shirt. He doesn't pause. The shirt is up and over her head and on the floor. His mouth is on her neck again, now free to roam, and his hands are doing the same, boldly sliding across her abdomen to cup her breasts, rubbing his fingers over her nipples through her bra. She's panting, gripping his arms, her hips unable to hold still, rolling back against him. He eases the bra straps off her shoulders and down, the cups peeling away, and his big hands close around her bare flesh and she gasps again, arching her back.

In the week since Castle started shadowing her, she has found so much frustration in his seemingly ceaseless chatter, the constant movement of his mouth. Now, in this hotel room, his mouth is having a very different effect on her.

She's on her back on the bed, naked, and his head is between her thighs, his tongue moving against her. Electric sparks of pleasure go rippling across her whole body with every movement. She throws her head back on the pillow and groans desperately, her hips twisting. He pulls her legs over his shoulders - somehow his shirt is gone too and his skin is hot against the backs of her thighs - and his hands are hard on her hips, holding her down while his mouth ravages her. She bursts apart in a sudden, inevitable rush, unable to stop the desperate noises escaping her throat.

Rick-from-Denver is just how she might have imagined Castle would be in bed - not that she'll admit to having imagined it - assertive, confident, unhesitating. And talented. Barely has she gotten her senses back than she realizes he's still at it, now pressing two fingers up inside her, twisting them until he finds the spot that makes her shudder and writhe on the mattress. His tongue is gentler now, building her back up. She moans and gasps for breath, can't at all find the words to tell him to stop, it's almost too much, give her a minute.

But he brings her right up to the edge, she can feel a second climax building, and she's ready, so ready for its undertow to pull her down, when he stops. She blinks dazedly at the loss of sensation as his mouth lifts off her and his fingers slide out of her. He comes slinking up her body like a predator, some kind of big deadly cat, and she can only watch, and reach for him with greedy arms. He's already naked and has a condom on and he drives into her without hesitation.

She cries out, her eyes slamming shut at the onslaught of sensation. Her arms wrap around his shoulders and some distant part of her brain is amazed by the power, the sculpted muscle of his body. Who knew he was so nicely toned under the expensive clothes, the carefree attitude?

She hears again the high-pitched sounds of pleasure rolling past her lips as he thrusts into her with long, slow strokes, his face pressed into the curve of her neck. She should maybe be ashamed of making those noises, of being here, of doing this, but she isn't. She needed this. Needed the release, needed the knowledge of what her infuriating new shadow feels like thick and hard inside her, the melting heat of his skin on hers, the weight of his broad body pressing her down. She lifts her knees higher around his hips and urges him on wordlessly.

He slides his hands down underneath her, long strong fingers wrapping around her thighs, and he pulls them up even higher still, angling her until he's hitting her just right with every stroke of his hips. She moans again and gives over to it. She comes hard, her throat dry, hearing him grunt urgently in her ear as the spasms of her body pull him over the edge also.

He rolls aside quickly and they lie still for a few moments, panting, sweaty. After a short span of time, the silence starts to feel uncomfortable. Beckett gathers her wits - not without a struggle - and sits up.

"Kate?" he asks, his tone carefully neutral. The use of her first name startles her briefly, until she remembers the game - the pretense under which they came here, did this. Gratefully, she pulls the act around her like armor.

"I gotta go." She stands up - wincing a little bit, wobbling a little bit on unsteady legs - and finds her clothing. She doesn't look at him until she's fully dressed, with her purse over her shoulder and her coat in hand. Then she glances over and finds him still lying on the bed, naked, watching her without expression.

"Have a nice flight," she mutters, and leaves.

It's not until she's in the elevator again, headed down, that it occurs to her that they never kissed. His mouth was all over her body, but never on her lips. She clenches her thighs together, groaning deep in her throat, fighting the urge to push the button again and ride back up to him. Oh shit. She can't, she has to put this behind her, but oh God, how the hell did she fuck Richard Castle without ever kissing him?

She goes home and gets into a hot shower, stands under the spray shaking her head and thinking, shit, how did this happen? What has she done? Exactly what she swore she wouldn't do, that's what. Gave in to the famous Castle charm. Gave him just what he wanted, and now he'll think that she's ... whatever he thinks of all those other women who appear with him in the gossip pages. Never the same woman twice, if Page Six is to be believed.

Scowling with self-disgust, she dries off and puts on pajamas, eats something out of a takeout container from the fridge that she doesn't see or taste, and falls into bed. She refuses to let herself think about it any more.

The next day she's at work as usual, wearing another turtleneck. Her thighs are a little sore, her hips a little bruised, and she's entirely on edge from wondering what happens next. Will Castle even bother to show up, or has he gotten what he wanted and decamped back to his flashy life? Which is what she has been wanting him to do from the beginning. Isn't it?

He does show up. He behaves entirely the same as always - as if nothing had happened between them. He high-fives the boys in greeting and irritates her with his obnoxious comments; he's boyishly, ghoulishly excited when they get a call for a new murder.

Okay, she thinks. She can do this. It was a one-time thing that they'll never talk about, if that's how he wants to play it.

The second time happens a few days later, after they solve the next case.

They run down their suspect in a hotel room, and after they've made the arrest, as her team is striding out through the lobby with the suspect in handcuffs surrounded by uniforms, Castle says, "Nice bar in this place. Bet they serve Stoli."

Ryan and Esposito stare at him, bemused. Beckett quickly steps in with snark, which is already firmly established as her role in this weird little team.

"If you want to go knock one back while we get on with the real work, Castle, feel free."

The boys snigger and they all move on, the incongruity of Castle's comment forgotten. She carefully doesn't look at him.

But later that evening, after the paperwork is finished, she's at that hotel's bar, and so is Castle. The bar does indeed serve Stoli. And the game begins again.

This time Rick-the-salesman is from Chicago, and this time Kate-the-businesswoman is a traveler too, because why the hell not? Beckett has mentally fleshed out her character some more. Now she's a security consultant from L.A., here for a week of client meetings.

And this time she makes him work for it a little harder. Kate-the-security-consultant is no pushover. She's unmarried, and gorgeous - yes, she knows exactly how hot she is - and she doesn't have to take any crap from any man. But Rick flirts skillfully; he's too suave for words; and of course she allows herself to be won over. Soon enough they're leaving the bar together. He reserved a room in advance this time, and she carefully doesn't think about what that means.

In the elevator, she leans against the wall, studying him. He raises his eyebrows and is perhaps about to say something, when she pounces.

She takes the kiss that she didn't get last time - the kiss that she hasn't been able to stop thinking about - and it's everything she dreamed of and more. It's delicious. She's practically climbing his body, her fingers clawing in his hair, her tongue invading his mouth. He grunts briefly in surprise and then his hands come up, boldly cupping her ass with both wide palms, yanking her against him. His tongue meets hers in a messy, wet clash. Her body is on fire, crackling with need.

The elevator doors open with a ding and they stumble out, hands groping everywhere. Somehow they make it down the hall to the room and inside.

She's feeling a lot more aggressive than she was last time, fierce with the need to regain control of whatever the hell this is. She slams him back against the door and drops to her knees before he has a chance to move. He gasps loudly when she tugs him free of his jeans and boxers, engulfing his tip in her mouth without preamble. His head slams back against the door, fingers curling convulsively around air as she runs her tongue down his length and back up again, her hand stroking.

She works the button of her own pants with her other hand while she's sucking him; her heels are kicked off and her fingers are inside her underwear, teasing herself with a light touch. His whole body is vibrating against the door with the strain of trying to control himself.

She brings him right up to the edge, like he did with her the last time, and then she pulls off. Rising to her feet, she grabs him by the front of his shirt, spins him around, and shoves him onto the bed. She climbs on top of him before he has a moment to catch his breath. She's already got the condom in her hand, kicked off her pants and underwear, and in another instant she's sinking down on him.

He groans as she takes him in, and it's ridiculous - they both still have their shirts on - his hands are moving quickly to remedy that, opening her buttons in a flash while she's rotating her hips and sliding down onto him. She leans over him and his long arms reach behind her, flicking open the clasp of her bra, pulling it off. He tugs her down until he can get his mouth around one breast, his teeth scraping, tongue circling, and she groans deeply.

She rides him harder, pressing herself forward over him, her hands digging into the mattress on either side of his head. His hands wander across her back, down to squeeze her ass again, and he pulls her in tighter so that she's rubbing against his pelvis just right with every movement. She gasps and moans, shuddering as her orgasm rolls over her. She lets herself collapse onto his broad chest as he pushes his hips up into her and groans out his own release.

Her head spinning, she rolls off and sprawls on the bed, panting. Her whole body is buzzing deliciously. She lies still, watching him slowly gather his wits, sit up, lean over to dispose of the condom. His shirt is still on, half-unbuttoned; his pants are bunched around his knees, his socks still on too. He looks down at himself for a moment, blinking fuzzily.

Then he kicks the pants and boxers off, brings his fingers to the next button of his shirt, and opens it. He looks over at her as he moves down to the next.

"Go again?" he asks, his tone silky, his mouth curving in that annoyingly sexy smirk of his. He finishes the buttons and shucks off the shirt.

She sits up next to him, runs her hands greedily over his well-muscled chest. "Hell yeah."

He growls his approval, pushes her back down onto the bed, and begins to work his tongue down the length of her body.

By the time they finish round two, it's getting late and Beckett is starting to feel hungry. She dresses quickly, forcing her overused muscles to obey even as they scream in protest.

"Nice meeting you," she says once she's put back together. He grins, pulling his boxers back on.

"Give my regards to Hollywood," he replies, and she tosses her head and leaves.

She makes it home and collapses on the couch, her legs like jelly. The ache between her thighs is almost strong enough to slip over the line from pleasant to uncomfortable. She forces herself to get up and eat something before sinking into a long hot bath.

Just like last time, the doubts and worries begin to creep back in as the intoxicating high of the sex wears off. She wonders again what to make of this. So much for the idea of it being a one-time thing … but then what is it? Why did Castle start this game; how could he have known it would work? How could he have known that pretending to be strangers was the only way she could be comfortable letting him get close? Physically close, that is, she tells herself hastily, biting her lip. That's all it is. It's just sex. That's all Castle wants with her, and it's all she wants with him.

She's lying to herself, but she can't let herself see it. She refuses to think any deeper. She's determined to cling to the belief that it was just meaningless sex - both times. And if it happens again, the same.

The next day, again, Castle is his usual self and so is she. They don't talk about it. She doesn't think about it. She's grateful for paperwork that gives her an excuse to spend most of the day in her chair.

Thanks for reading! This story will be either 3 or 4 chapters depending on how I decide to break it up. Next chapter will be posted tomorrow.