"Mistress Heat," Castle greets, entering the private room with the usual smug, self-satisfied grin strung across his lips, the spark in his eyes twinkling in the red glow of the private room. "How's business today?"

"Attempting some small talk form of foreplay, Rick?" she inquires with a rise of her eyebrow. She's been undercover at Lady Irena's House of Pain for two weeks now and the extended operation is finally coming to an end, but of all the clients she's seen (all screened by the Vice squad before they're allowed anywhere near her), Richard Castle is definitely her weirdest.

"Mm, no, but is that something that gets certain people going?" he asks, taking a seat on one of the leather dungeon chairs and retrieving his notebook from his inside jacket pocket. "Should I make a note of it?"

"Don't you have enough notes on the lifestyle?" Kate replies, abandoning her post at the other end of the room, the ridiculous red velvet chair where she perches in wait of every client that walks through the door of her 'dungeon'.

Rick has been showing up for thirteen of the fourteen days she's been here and not once has she performed any sort of sexual fantasy for him or executed any strange fetish; he's booked thirteen appointments with her for research. Part of her feels a tad guilty, wishes she could inform him that she's actually not a real dominatrix, and while she may have the knowledge (extensive knowledge, at this point), she can't offer him the true insight he came here seeking.

But of course, the manager had assigned him to her of all the women in this massive BDSM club. She has a feeling they did it on purpose, placing the civilian seeking conversation with the undercover cop so he wouldn't take up any of their real dommes' time.

"What can I say, you fascinate me," Castle answers with an innocent shrug of his shoulders, but the crisp blue of his eyes darkens ever so slightly to that midnight hue she's seen before when the topics become a bit… heated.

There's an undeniable attraction between them, a current of electricity that almost has her wishing that touching was allowed, or rather that she met him under different circumstances entirely. Could touch him on her own time.

"Well, get all of your questions out now, Ricky," she teases, relishing in the scowl he tosses her for the use of the nickname he loathes. "Today is our last session."

"What?" Castle questions instead of whines, a genuine frown creasing his lips rather than a petulant pout.

He can be childish, egotistical and annoying, but he can also be intelligent, charming in a way that doesn't make her skin crawl like it does for the majority of men she meets these days. He can be sweet and enticing, attractive to her mind and her body, but regardless of what she thinks of Rick Castle, it doesn't matter. Vice has all the evidence they need and plan to make an arrest today before her shift is over; she'll be hanging up the lacy, more 'conservative' (there's only so much she'll do for a case and when it comes to her attire; she'll be saving the leather corsets for her own bedroom, her own fantasies) black negligée for the last time within a couple of hours.

"Are you quitting?" Castle asks with a strange hint of concern drawing his brow into a deep furrow. "Did someone do something inappropriate-"

"No," she chuckles, crossing her arms over the dip of the sheer fabric between her breasts as she approaches him. "Do you really think I'd let someone do something I didn't want them to do in here, Castle?"

Most men would swallow hard at the authority in her tone, the intimidating stance of her presence towering over them, but Rick merely gives her a proud smirk. She's met with a few strange men within the last two weeks, her clientele kept to a minimum, but no one unnerved her quite like this one does.

"Mm, no. Not unless they wanted the heel of your stiletto through their hand," he muses and she grins at that, pointedly clicks the heel of her stiletto on the gleaming black of the marble floor before she reaches the chair he sits in. "You are quitting, though?"

"I never planned to be here long term," she states with a shrug, the truth, technically. "It's been an interesting experience, but I'm ready to move on."

Also true. So very true.

Castle nods his head in understanding, but his face is contemplative, thoughtful, and she's almost afraid to ask what he's thinking. But the suave mask he's worn since the day he walked in here slips back into place, falling only on rare occasions when he's let a few stories about his fifteen year old daughter escape his lips or conversed with her like they weren't in a sex dungeon, like they were simply friends or two people on a date. But that wasn't happening, couldn't happen; God knows he's already tried hard enough to take her out for coffee in the last two weeks.

"Any fantasies you want to act out before you lose the chance for good, Mistress Heat?" he teases, his eyes roaming the room, lingering on the assortment of chains, whips, paddles, and floggers decorating the adjacent wall, before returning to settle on her with a good dose of challenge and intrigue.

Kate hums, just to witness him squirm the moment he thinks she's taking his offer seriously. "There is one hot, wild, kinky thing I do like doing," she muses, watching the control on his demeanor go slack, those bright blue eyes going wide and hungry for her words. "But I just don't think you could handle my fantasies."

Castle straightens in his seat. "I'm game for anything."

Beckett laughs under her breath and shakes her head, but Castle rises from the chair, his notebook cradled at his side.

"Okay, I knew I wasn't going to get anywhere with that one, well maybe for a second - but seriously, I don't even… I want to see you again. Outside of this," he professes with the motion of his hand sweeping the room, none of that usual amusement lighting up his eyes, none of the golden glitter of fascination he often wears. He looks so sincere, so hopeful, and – this is not part of the plan.

Kate sighs and turns from him, drifts towards the sleek table a few feet away to prop her hip against. "I told you, seeing clients outside of the business is-"

"Prohibited," he finishes from over her shoulder, his footsteps echoing softly through the room as he follows her. "But I won't be your client after today, will I? And really, was I even a client to begin with? All we did was talk about research for my book."

"Same principles apply," she mumbles, tensing once she feels Castle ghosting at her back. He won't touch her, that's against the rules of the room, but he comes as close as he possibly can.

"I've been coming here every day for two weeks and yeah, I learned a lot, but the dominatrix aspect in my book was minor. I wanted it to be authentic, but all I needed was a single session to accomplish that," he confesses and Kate purses her lips, spins on her stiletto to glare at him, because she's only known him for less than two weeks and she already hates him.

Hates him for showing up every day, for showing so much interest in her and the person behind this fake identity she's been living, for making her laugh and smile throughout the past two weeks. It's been so long since a man has held her attention, has elicited sparks in her stomach that catch fire in her chest, and she wants to just explain the truth, make it all so much easier. But if she does that, then it becomes more complicated. It becomes real.

And if he knows there are no longer any rules or regulations restricting them, he'll never give up on pursuing her and she just isn't sure she's ready for that. For anything that could mean something.

"Can I at least have your name?"

"You know, Castle, maybe I can share one of my fantasies," she hums, watching his eyebrows hitch. "Willing to wear a gag?"

He huffs and she moves to stalk past him, head for the door and cut this final session short, but Castle surprises her. He snags her by the wrist, he breaks the rules, and she's too stunned by the curl of his fingers, the sear of his skin branding hers for the first time, to stop him.

And that's all the inclination he needs to reel her in.

"That's not your fantasy," he murmurs, the blue in his eyes turning feral, bright flames that dance with a deadly combination of arousal and determination. "No, you'd want to hear what you'd be able to do to me, the sounds you'd drag out of me-"

"Rick," she breathes, horrified by the husk of her voice, the circle of his thumb along the inside of her wrist painting a halo of heat over her pulse.

"What's the matter? We talk about sex all the time," he muses, tilting his head at her in feigned curiosity because he knows exactly what he's doing.

They discussed sex, yes – the in-depth psychological workings of it that came into play in this job, the root of the slew of existing fetishes, the desire for control, for the submission of it – but they've never spoken a word of what sex between the two of them would be like. And she wasn't about to start now.

"You need to go," she murmurs, averting her eyes to the door, willing the flames of her cheeks to die down.

"You're in control every day. If we were together, if I was yours, you'd want me to take charge every once in a while, wouldn't you?" he continues without hesitation, his gaze flicking to her mouth. "You'd let me tie you to the bed, touch every inch of your skin with my hands, my mouth-"

"Castle. Stop it-"

"But you wouldn't be able to stand being tied up for long, being unable to touch, to grip and tug and direct me where you wanted me the most, and I wouldn't be able to hold out when you begged. I'd untie you, let you dig your nails into my back while I-"

She shuts him up with the surge of her body, the seal of her mouth over his.

Castle immediately lifts his free hand to cradle her jaw, hold her there. Kate moans around the fit of his lips, the stroke of his tongue to the seam of her mouth that she grants him access to all too easily. She's breaking all of the rules, every single one of them, but she shakes his fingers from her wrist so she can grip the front of his shirt, drag his body in tight and hot against hers.

"You don't know me," she growls, digging her teeth into his bottom lip, earning the roll of his hips towards her.

Her breath catches in her throat and her legs spread a little wider, eager to draw him in deeper, to feel what she does to him.

Castle stains his lips along her jaw, scrapes his teeth to the sharp edge of bone, until he reaches the sensitive spot just below her ear that has her entire body threatening to quiver. "No, but I want to. You're so much - there's so much more, I can tell. I want to know all of it. Wanna know you."

Oh, he doesn't. He really doesn't. She's a mess, still so ragged and torn up over her mother's murder even after ten years, over all the dead ends and disappointments, still so hollowed out by grief. He wouldn't survive her, no one else has.

Kate chokes on a whimper as Castle opens his mouth at the throb of her pulse point, his hand tangling in the tousled curls of her hair, the other trailing down her side, over the rise and fall of her expanding ribcage, slipping beneath the thin cardigan she always wears over the lingerie. The splay of his palm over the satin and silk stretched across her side has heat seeping through the fabric, scorching her flesh, and – it's not enough.

She jerks him back to her mouth with her fingers at his ears, claims his lips with a desperate noise she should be ashamed of, but isn't. Not when Castle is canting into her, backing her up against the table as his hands burn across her body, ceaseless in their exploration as if he just can't find a place to settle.


"Kate," she gets out, banding her arms around his neck and hooking her leg at his calf, jerking his body into her before he can speak, before he can pin her with wide eyes or that subtle look of awe he adopts each time she reveals even the smallest tidbit about her personal life. "It's Kate."

But the press of Castle's lips is gentling, the grip of his hands softening. She sighs, hums at the adoration his mouth brushes along hers, before he pulls away. He drops his forehead to rest against hers while his hand squeezes the back of her knee caught at his hipbone.

"Kate," he echoes, her name like silk in his mouth, and she nudges her nose into his cheek, parts her lips and tries to reclaim his. "Am I your last client of the day?"

"Yeah," she mumbles, managing to snag his top lip between her teeth, nipping on the tender flesh before sucking it into her mouth, soothing it with her tongue.

Castle groans and buries his fingers in the lace at her lower back, kissing her hard before releasing her mouth with an audible pop.

"Come to dinner with me," he bargains, loosening his grip to spread his fingers like wings across the small of her back, the tip of her spine that bows forward for him. "Or coffee. A walk through the park. Whatever you want."

"Castle, I can't," she breathes, her leg easing back down, the toe of her heel skimming the floor, but Castle nudges in closer, nuzzles his face to her neck.

"We already broke all the rules," he points out and she can't help it. She laughs, combing her fingers through the fine hairs at the base of his skull and shaking her head as he smiles against the skin of her throat.

"No, not because-"

The door to her private room bursts open.

Kate immediately grips his shoulders, prepares to push him away, but she isn't quick enough and the shouting begins before she can call her colleagues off.

"NYPD! Step away from her, dirt bag!"

"Yeah, hands off, punk!"

Castle stiffens in surprise and surrenders one of his hands to the air. He leaves the other curled at her waist while he stares between her and the two NYPD detectives in the doorway, lust and bewilderment bleeding through his eyes.

"Uh," he clears his throat and glances back to her. "Kate?"

Beckett huffs and waves her hand for Ryan and Esposito to lower their weapons, feeling Castle relax against her once there's no longer two guns aimed at him. "It's okay, boys. He's not a client."

Rick's fingers squeeze at her hip in askance, in confusion, but he doesn't speak, doesn't object to the lie that Esposito and Ryan seem to buy with a good dose of skepticism.

"Did you get the guy?" she says instead, arching her brow expectantly.

Esposito nods, holsters his weapon.

"Yeah, we got him. Just clearing the rest of the area, but the head of the place said you were in here with one of your regulars," the fellow detective informs her with smug amusement leaking to the corners of his mouth. "Using your dungeon for personal time, Mistress Beckett?"

Kate shoots him her best glare and pulls her flimsy cardigan tight across her chest, even though the broad wall of Castle's is blocking her from view, for the most part. "Shut up and leave so I can get dressed. We'll meet at the station in twenty."

"You got it, boss," Ryan returns a little too cheekily, sharing a smirk with his partner before the two of them are closing the door and trotting down the hall towards the exit.

The second they're alone, she knows exactly what to expect.

"You're a cop?" he gasps, staring back at her with his eyes wider than she's ever witnessed, starstruck and baffled and even more turned on than he was before they were interrupted. "An undercover cop? This entire time - holy shit, Kate, you-"

"I'm sorry for lying," she sighs out. But Castle is cupping her face in his palms and vigorously shaking his head before he moves in to plant another kiss to her mouth, the work of his lips hot and fast and pulling her up on her toes like a puppet on a string to give as much as he takes.

"You are extraordinary," he manages, panting hard against her lips. "I knew it all along, but you're even more incredible than I expected, Officer."

"Detective," she corrects him. "Detective Beckett."

"I so regret not living out a good cop bad cop fantasy now," he groans and despite herself, she smiles. She paints her grin across his mouth before dropping down to the balls of her feet, snagging her fingers in the collar of his shirt and tugging. "But ooh, if I'm not a client, what does that make me? Am I your boyfriend, Detective?"

"Any chances of claiming that title will be dashed at this rate, Castle," she warns, but he looks giddy with it.

"Does this mean we can go to dinner?"

Beckett rolls her eyes and shoves at his chest, steels her legs to remain steady as she steps free of his body's embrace.

"I have to head to my precinct, meet with the director of Vice as well as my captain, but later…"

"I can pick you up," he finishes, practically vibrating with the hope she can hear so easily in the words. "After."

For the first time since she's met him, even after she just made out with him, Kate feels the tiniest bloom of shyness spread through her chest, the butterflies that come with firsts - both kisses and dates - invading her system. Just this once, she embraces their arrival.

"You're not weirded out by all of this?" she questions, but Castle merely scoffs.

"Weirded out? No way. I already - I want you, Kate," he says, his voice factual, but dropping to a more serious tone, his eyes a deep, mesmerizing shade of blue as he snags her gaze, her fingers in his. "The fact that you're a cop? Honestly, it only makes me even more intrigued to get to know you. And learn how the hell you ended up masquerading as a dominatrix."

Her lips quirk and Rick leans in closer, caresses the curve of her mouth with his gaze. "Also makes me wonder what hot, wild, kinky things you might be able to do with those handcuffs other than arrest criminals."

"Keep dreaming, Castle."

"Oh, I will," he assures her, releasing her hand when she drifts away, towards the wall of bondage toys where her police cuffs lie in plain sight. He gasps as she plucks them from the peg of the wall, hooks them on her index finger, allowing the gleaming metal to sway as she brushes past him.

The delightedly stunned expression of his face has her lips blooming into a satisfied smile as she snags her bag from the floor and reaches the door. Kate curls her fingers around the handle and catches his gaze over her shoulder before exiting.

"See you outside the Twelfth Precinct in an hour, Castle."