Plot idea for this one came from yellowbrickrd, inspired in turn by The Big Bang Theory. And as always, editing, enthusiasm and general all-around love came from my sweet, lamblike cartographical, who has put up with my endless whining and stamping my feet with the greatest of love. Also, if you have not read cartographical's "Bang," go read it now. Go. Then come back and read this. You will be glad.

This one is unconnected to chapter 17; same episode, but different take on it. It picks up post-episode, after the conversation in the back of the ambulance. And will maybe require some suspension of disbelief. Um, yeah.

Chapter 21: 3x13, Knockdown 2.0

Always.

She's still wound up from the night, adrenaline buzzing through her veins like quicksilver. It's mixed with a delicate curl of warmth that swirls through her whole body every time she looks back at Castle. Castle. Her irritating, boyish, well-meaning, stubborn, loyal, resourceful, life-saving partner.

(He's a good kisser, too. Not that she's dwelling on it.)

By the time they finish giving their statements, it's around 2:30 in the morning. She glances at Castle, who's sitting by her desk picking at the bandage on his hand.

"Castle?"

"Hmm?" He looks up, and in his eyes she can see the energy that probably mirrors her own, the buzz of chemicals swirling through her system.

"You tired?"

"Not – not really. Still kind of antsy."

She nods. "Want me to take you home?"

He thinks for a minute. "I was going to ask if you wanted to grab a drink, actually. I think we've both earned it."

Kate bites her lip, carefully ignoring the way his eyes immediately focus on her mouth. A drink sounds good. She's still mentally all over the place, and she knows she needs to relax if she's going to get any sleep. And…he saved her life tonight. She's feeling – something. Something good. She doesn't really want to dump him back at his place and leave. "That sounds nice. Any particular place you had in mind?"

"Well, I do know a good bar…" he trails off. He wiggles his eyebrows suggestively, and there it is again, that flood of warmth in her veins that she's still not questioning.

At the empty Old Haunt, Castle flicks on a few lights that bathe the bar in a smoky golden half-light. Kate settles herself at a table as he pulls out his keys and starts rummaging through the cabinets. She's relatively sure they're going to get comfortably drunk and pretend a certain thirty seconds in that alley never happened. And honestly, that's exactly what she wants right now. Her official statement, currently in investigative hands, merely says she and Castle acted their way inside. Which is true. She didn't feel the need to tell the grumpy old officer who took her statement any particular details about Castle's tongue or where it ended up.

(Not that she's even thinking about it. Or his lips. Or any other part of his mouth. Really. She's not.)

"Aha! There it is."

Castle reappears from where he'd been rummaging through the cabinets, and Kate takes a closer look at the bottle he's brandishing. Of course. Red wine. His drink of choice in times of trial.

"What do you think?"

She's about to say yes, but – maybe it's not the best idea. Red wine is meant to be drunk on a couch, curled up by candlelight. Red wine is an aphrodisiac. It's a prelude to seductive glances, to vulnerable confessions and sitting too close together and accidental touches and timid half-kisses that get more confident and a lazy dance of tongues and hands sliding under clothing and moaning and –

She swallows. "Maybe not."

He shrugs, puts the bottle back. "What do you want, then? We've got our pick of the stock."

"What about tequila?" It's the first thing she can think of that isn't red wine. And it's not a bad idea. Tequila is fun. Tequila is fast and easy. It doesn't bring deep feelings bubbling to the surface.

(She is not thinking about its consequences in Heat Wave.)

"Tequila? You want to drink tequila?" He blinks a little, but shrugs. "Okay. Any particular – "

"Just pull out the cheap stuff, Castle. We don't need Don Julio to get drunk."

He raises an eyebrow. "Katherine Beckett. Are you implying I keep liquor of poor quality in this establishment?"

"Do you?"

He grins. "Well – yeah. College students come in sometimes."

She lets him pull out the tequila, a saltshaker and a bowl of lime wedges. It's been a long time since she's done shots. This is actually kind of nice. And Castle saved her life tonight. She can drink with him.

She sinks her teeth into the lime, her mouth watering at the sudden tart sweetness. A few drops of juice spill down her chin and she wipes them away with the back of her hand, pretending not to notice the way his eyes linger on her mouth as she does.

There's a pleasantly soft heaviness settling into her arms and legs when she finishes her next shot, wrinkling her nose as it burns on the way down. "This is really crappy tequila, Castle. I'm impressed."

"You wound me," he huffs in mock-indignation, filling her glass again. She needs to be careful. Kate holds her alcohol well, but she doesn't want to end up staggering. The adrenaline in her system has sent her body a little haywire, and she doesn't really remember the last time she ate.

(The shiver running through her skin is wholly due to the adrenaline of the night's events. Certain parts of them. Only the parts she's admitting happened. She's completely positive of it.)

She's impressed he's keeping up. She's drunk guys his size into submission before. Of course, Rick Castle is no slouch. And besides. This is his bar.

He won't let her do anything but drink ("Only a trained professional should be preparing drinks, Beckett." "You have no training, Castle.") and she's enjoying watching his pouring get just the slightest bit sloppy. His eyes are still clear enough, so she's reasonably sure he's still doing fine. Though he has no business looking at her like he is right now, like she's his and he knows it and this whole thing is a prelude to something dirty and raunchy and –

He's just buzzed enough to be clumsy, his hand wrapped in the bulky bandage, and he drops the saltshaker, spilling salt over his arm and the table.

The adrenaline is wearing off, warmth settling into her limbs, dark and liquid and slow. She's telling herself it's from the alcohol. Nothing else. But she can't stop staring at his arms. His sleeves are rolled up to his elbows, leaving his forearms bare, and she watches, fascinated by the subtle tensing of muscles under his skin. He's strong. She knows that. Seeing the brutal side of him – the side that would have killed the man who almost killed her – shook her. It's a new side of him. It's dark. It's – she doesn't know. It makes her chest flutter.

He's about to reach for a towel, wipe up the mess of salt, but suddenly she can't let him. She can't let him clean it up, brush it off like it never happened. The thought of simply sweeping away the mess gives her an inexplicably visceral reaction. Without thinking, she snags his hand, her fingers curling over the white bandage. She tugs it towards her, leans over, and licks the salt off his arm in one smooth motion.

His skin is sharp with salt and tang of sweat and her mouth is suddenly dry and it might not just be from the salt.

She knocks back the tequila to wet her throat. When she looks up, chancing a hesitant look through the dark curtain of her soft lashes, she meets his eyes to find him frozen. Castle is motionless, staring at her, mouth open in shock, like he has no idea how to respond to the fact that she just, of her own volition, licked his bare skin. Heat curls through her veins, tingling and weakening and as intoxicating as the alcohol.

(It's not the best idea she's ever had.)

But then he holds up a lime, and before she thinks too hard, she snags his hand, holding it still, and bites into the fruit. His lips part, and his throat bobs as he swallows unevenly, watching her with dark eyes. Lime juice runs down his hand. She leans over and licks the trail running down his hand, her tongue swirling over his skin. She can feel his pulse thrumming hotly under his skin, the quick beating under the taut lines of his wrist.

He pulls her chair closer to his, his hands sliding to rest on her thighs as he sits on the front of his own chair, and it takes all her scant self-control right now to keep from pressing her legs together. Bad idea. Bad, bad idea. His fingers press into her, hot and sure and so very wrong. But oh, oh, it feels so good, so terribly, terribly good, she just can't help herself.

His hand slides into her hair, his fingers tightening, and then his breath is on her cheek, hot and moist and too much, too much –

It doesn't really register what he's doing until he's tugging her shirt up and it's over her head. She raises her arms obediently, and it's not until the cool air raises goosebumps over her bare skin that she realizes she's not wearing a tank top.

She knows, distantly, that this is fast becoming a bad idea, a terrible idea, but the warmth has dulled her reasoning in favor of sheer sensation, and the delicate pressure of his fingers trailing up her bare arm leaves a trail of unbearable heat that makes her shiver and bite her lip. He needs to stop looking at her, stop with that hungry gaze, the darkness in his eyes she can't handle because it means too much, way too much.

Just – just don't look – it's not real – it's not –

Her eyes flutter shut and she holds her breath. Stupid, stupid idea, Kate. The sudden darkness makes her nerve endings sizzle, her skin awake and aware and terribly alive. She can feel him, the heat from his body burning over her bare skin, the rush of his breath making her weak. His hand slides over her shoulder, tugs her hair back, baring her neck, and she swallows hard.

There's a faint sting of salt on the skin of her neck, sending an unbearable tingle through her bloodstream, and she only has time to think can we really do this? before his other hand settles on her waist, light and hot and sure.

His wet mouth hits her skin and she gasps, because this is not good and they shouldn't –shouldn't –

He leans into her and she has to catch herself, falling back on her wrists on the table. Before she can react, Castle's settled between her legs, his chest pressing against hers, pushing her back down on the polished wood of the table. He braces himself, leans over her, and she has to stifle a moan as his tongue slides over the sensitive skin of her neck, the thin scrape of the salt mixing with the soft wetness of him until she's gasping, her chest heaving.

Cool liquid drips over her skin, her collarbone, and it takes her a second to realize it's tequila.

He's pouring tequila on her chest.

Oh God –

A strangled breath escapes her as he starts sucking the alcohol off her skin. He's getting bolder, his hands sliding over her body, pushing her lower onto the table. She sinks back onto her elbows and then suddenly falters as his thigh presses hard against her. Her back arches involuntarily, crushing her chest against him, and as his hand slides up the line of her neck, his teeth scraping lightly at her skin, she feels unbearably hot, shaking, helpless under him as he sucks at her neck, a vampire drinking her in.

The tequila has warmed against her, the soft trickle of liquid painfully slow, streaming over her slick skin, sticky and spreading over her body. His tongue follows it, trailing down to her stomach. Her breath is coming fast and hard, her chest heaving as she clutches the edge of the table, tightens her knuckles to stop herself from reaching for him. They need to stop. They need to stop this right now.

But she's not cheating. It's not kissing. It's not on the mouth. They're just – oh God – just – having a drink –

His tongue swirls over her navel and her eyes roll back in her head and she can't breathe and – and – he's not – not going to – is he? – no, he can't – he won't undo her belt –

She can't form a single coherent thought beyond the rough wet pressure of his tongue over her skin. Her fingers slide through his hair in spite of herself. She's not naked. They're not naked. They're not actually –

He pushes her all the way down so her back hits the smooth wood of the table, her head resting on its surface, and his mouth comes back to her shoulder, teeth nipping lightly at her skin.

Suddenly she needs to touch him. She needs to – she can't kiss him. She needs –

Kate tugs him closer, hooks her ankle around his leg, gasps at the sudden rough friction as his pelvis rocks into hers. She sucks on the taut line of his neck, feeling the sharp breath he draws in against her. Her fingers curl weakly against the nape of his neck, sliding along the line of his broad shoulders. His hips rock roughly into hers and she has to swallow a moan.

She tugs blindly at his shirt, her hands sliding over his skin, desperate to touch him (anything but kissing), aching for more. She gasps against his throat, her fingers tracing lightly over the subtle contour of his abdomen, the tapering of muscles disappearing under his waistband to his groin. He lets out a tortured groan, and his eyes flicker shut as he swallows.

Oh, it would be so easy. So very easy. He's as turned on as she is. She could just flip him over, straddle his waist, undo his belt, reach inside –

- oh God.

I have a boyfriend.

I can't do this.

She freezes, the horrible truth hitting her like icewater, like a tidalwave, so overwhelming that her hands start shaking uncontrollably. No, no no no –

She shoves him off of her, ignores the shock painted across his handsome face. She can't look at his mouth. Her cheeks burn, guilt swamping her, her head spinning with a wave of heat and alcohol and arousal and shame. The whole reason she consented to get drunk with him is because she's with someone else, someone safe. They've both been cheated on. They both know better.

They shouldn't have done this.

She needs to get up, needs to get away from him, needs to (shit) put her shirt back on over her sticky, sweaty skin, but she's so dizzy she can't move. She drops her head into her hands. Fuck.

"Kate – "

"Please. Castle." She won't look at him. She can't. She pulls herself off the table. Where's her shirt? She could have sworn it was –

"Here." He holds it out, and she snatches it with shaking hands, trying to pull it over her head. She's shaking and terrified and sticky and uncomfortable and sweaty, and she can't find the armholes, and it's sticking to her skin and she just needs to get out, get out of this mess, get out of this bar, get out of this seductive, dangerous atmosphere –

But then she feels his hands on her arms, untangling her sleeves, easing the collar of her shirt over her head and freeing her hair, letting it fall over her shoulders. Her eyes are stinging. He needs to stop. He needs to stop being so gentle and sweet right after making her want to do things to him in the middle of an empty bar that she's horribly ashamed of. Because she's starting to sober up. But she still wants him.

"Kate –"

"Castle – I – I can't – "

"Kate, please – "

"I can't – "

She can't give him a chance to persuade her. She grabs her coat and flees out the front door before he can stop her.

The sharp, cold night air helps clear her head. She pulls on her coat and sags limply against the brick wall behind her under the pooling light from the streetlamps. Oh. Oh, God. What just happened?

(She's never felt like that with Josh.)

A shadow falls over her, and she's not surprised. Of course he's here. His hands come to her shoulders, running over her arms. "Kate – "

She can't answer, can't move, knows she should stop him but doesn't as he leans in. She tenses, waiting for the inevitable –

- but he doesn't kiss her.

He wraps his arms around her, pulling her close, and she sinks into his warmth, the softness of his shirt, dwarfed against the broad frame of his chest. His lips press a soft kiss to her temple and she's just drunk enough that her filter doesn't stop her from wishing, so very hard, that it could be this way.

But even as she leans into his touch, she knows it can't – can't –

"It's not okay, Castle."

He stills, his mouth still on her forehead, and finally he drops his hand, lets her go. "I know, Kate. I know."

They leave in opposite directions. Kate knows he's looking back. So she forces herself not to.

By the time she gets back to her place, she's sober enough to know that this isn't over.