a/n: I was going to make this KMC, but didn't really tie it to an ep.

He's spent the past two months following Kate Beckett around, but he is two hundred percent unprepared for the night they have to go undercover to a nightclub.

She steps out of the precinct bathroom and he stares.

"Whoa."

It's only the second time he's seen her legs and he's absolutely certain he wants to see more of them.

She's glaring at him with her normal irritated expression - it's sexy - but now it's framed under darker lashes, the heavier sweep of eyeliner making her eyes look huge. And that tiny, tiny little skirt. It's miniscule. It's tiny and skintight and glittering.

She turns away and the air leaves his lungs. Because her ass - her ass is perfect, of course, he expected nothing less. But her top. That deep purple, silky fabric, so gorgeous on her pale skin, and her back is bare. From the base of her neck to the bottom of her spine. She's all long, slim lines, the curve of her ass, the endless legs in those indecent, strappy silver shoes.

"You coming, Castle?"

Ignoring the bristling anger in her voice, he hurries to follow. He trails several steps behind and doesn't even try to hide the fact that his eyes are firmly glued to her ass.

It's been a while since he's gone clubbing with anyone, let alone this feral, sexy creature.

His mind can't quite grasp it. Beckett is a cop, straightlaced, buttoned-down quite literally, all short hair and high collars and strict rules. And suddenly this lithe, gorgeous woman is standing in her place, half-naked and not wearing any kind of a bra that he can detect and moving against his body like an animal. He's getting a better picture of her, of whatever kind of wild child she was once, and it's taking all his scant self-control to keep his hands off the more inappropriate parts of her. As it is, they're resting gingerly on her hips, inches away from a sexual harassment lawsuit as she sways rhythmically against him to the throbbing beat of the music.

She presses up closer against him, ostensibly to look over his shoulder for whatever bad guy they're chasing. He's forgotten. He's forgotten everything except the heat of her body on his, because his hands are slipping over her ass and his blood is quickly pooling in one very specific spot that isn't his brain.

Her fingers curl around the back of his neck, twining slowly through the short hairs at his nape, and he can't form coherent thoughts that don't involve her naked and up against the wall of his shower. Because she's getting sweaty, and as he drags one hand over the slick skin of her back, he's seriously considering the possibility she's getting into this as much as he is.

"I don't see him," she says (gasps) into his ear, and his eyes roll back. "Hang on -"

She twists or moves or something, and he has to bite back a groan. Because this maybe started with him leering but now she's flat-out grinding on his leg and this is getting serious.

"He's - wait, that - is that -" she lets out this little growl of frustration that does nothing to help him control his lower body. "He's in the back. Where they're - oh, the bouncer -"

If she doesn't stop moving -

"Castle," she hisses into his ear. "We need to get thrown out."

What?

"The guy. He's back there, we need to get thrown out and we'll see him."

"Oh - okay -" Does she realize exactly what she's asking him to -

He slides his hands over her back and his whole body tightens. Damn.

But she huffs, her breath hot against his skin as she glares at him. "Come on," she grumbles. "Do you even know how to get thrown out of a club?"

He grits his teeth. She wants to get thrown out?

He'll get them thrown out.