Ok, so…while this is NOT my first foray into writing fanfiction (I'm old enough to have been around for the original Mulder and Scully fanfiction years), fair warning that I haven't written Castle and Beckett for YEARS. Seriously years. Maybe not since the show was actually still on the air. And I've never written a story with them, only collaboratively played around with the characters with a few friends. So hang on, because this one might be a bumpy ride. I do not have the story mapped out beyond a little bit in my head…I'm not that organized. I do have a lot of free time as I freelance and work from home at the moment, which bodes well if the Caskett muse strikes. And I don't promise a regular update schedule…however, I will tell you that feedback and reviews get me giddy, and when I'm giddy I am more inclined to write.

This story is inspired by one I read on here called "Instant Connection" by ipreferwestside. This story is not copying that one, but it did give me the inspiration for the one night stand idea…I'm just going in a different direction with it, different details and building it in a different way. And there are several season 1 episodic moments that will need to be fixed and added to/rewritten for this.

I do not own Castle. I don't own the characters, I just like to play with them for awhile in my sandbox...and I could definitely play around with Nathan in more than a sandbox...

Also…I write smut. So…sorry if that's not your thing. Be forwarned. I do try to keep it tasteful though! And…usually story driven, and a lot of times you can kind of skip through that part. But this first chapter is a lot of it because...well...one night stand.

Fancy fundraisers were not Kate Beckett's scene. She wasn't thrilled about being at this one, but Lanie had insisted she go. It had been 3 months since she and Will had split, and Lanie had insisted Kate needed to get herself dressed up and out of her self pity for one night. Kate had insisted she was not wallowing, as Lanie had implied, but had begrudgingly agreed. Now that she was here and had already had a couple of drinks, she had relaxed a bit and even found herself enjoying the atmosphere. She was wearing a red dress that fit her in the right places and led to every single man (and plenty of married ones too) unable to keep their eyes off her…and she found that she was enjoying the attention more than she would admit. She also would never admit it to Lanie, but her friend had been right; this night of men openly appreciating her looks made her feel desired and sexy and was the perfect prescription to get her out of the funk she had been in since Will had chosen to take a federal job in Boston over remaining in New York with her.

Looking toward the bar, she saw him and her jaw dropped slightly. Richard Freaking Castle. Her favorite author. She had to ask herself what he was doing there at a fundraiser for the NYPD. Though, as she finished her vodka martini, she found that maybe she didn't care. If not for alcohol running through her system, she never would have had the thought that crossed her mind. The perfect way to feel sexy and desirable and wanted was a taudry, fun night full of wild sex…and she had just laid eyes on the perfect man for the job. She knew enough of what she had seen on Page Six to know that he was a playboy, which was perfect; he wouldn't expect more than that night, and he should be relatively easy for her to entice since he seemingly hopped from bed to bed. What the hell…I look fucking amazing, she told herself starting in his direction. If Lanie only knew the beast she'd awoken by making her go to that fundraiser, she may have never sent her.

Castle sat at the bar surveying the room. He didn't always go to fundraisers like this, but he was friends with the mayor...had been personally invited, and his divorce with Gina had been finalized a few months ago. His mother and daughter had both insisted he go to this one…get out of the house and give them a night of peace for a change. Alexis had basically told him that he was starting to drive her crazy. She had reasoned that the fundraiser wasn't some crazy party; it was to raise funds and awareness for the NYPD. He was at one of the safest parties in the city where there was no way he could do something immature and stupid. As he finished his drink, he caught sight of a breathtakingly gorgeous woman in red heading in his direction, and he swallowed hard, thinking just how much his daughter may have underestimated his ability to be both immature and stupid.

Having the feeling he was going to need it, he quickly ordered himself another Scotch. He didn't even bother hiding the fact that he was checking her out as she made her way toward him at the bar. "Hi…Rick Castle…" he offered her a charming smile as she leaned against the bar.

Oh he was definitely interested. This was going to be easier than she thought. Biting her lip slightly, she gave him a smile. "Nikki." She didn't think twice about giving him a fake name. There was no way in hell he was getting her real one; he wouldn't need it. This was a one and done thing tonight.

He swallowed hard again at the way she looked with her lip between her teeth. Oh boy. He was definitely about to do something stupid. And immature. "Can I buy you a drink?" he offered, cursing himself that he was unable to come up with a better pickup line.

She tugged her lip between her teeth again. Noticing the bartender had just brought his drink, she leaned in, reaching behind him and grabbing his glass. She met his eyes with a seductive look and let her tongue tease the rim slightly. Downing the liquid in a matter of seconds, she placed the empty glass on the bar with a raised eyebrow. "Just did. Thanks."

He just stared at her. That had to be one of the hottest things he had seen…and he had seen a lot of hot women doing really hot things. Finally he realized he should do something other than just stare at her, or she would probably lose interest. "Care to dance?" he suggested.

"I have a better idea," she replied with a grin, taking his hand and tugging him after her.

He followed willingly, using his vantage point to enjoy the view of her ass and her curves. Oh, he would go just about anywhere with her right then. "Where are you taking me, Nikki?" he found himself asking.

"Somewhere we can have a little more…fun," she looked over her shoulder, the look in her eye leaving no doubt the kind of fun she was referring to. "Unless…you'd rather stay here and drink expensive Scotch the rest of the evening?" she arched an eyebrow in his direction.

"I'm a fun guy," he quickly answered. That was a no brainer question. She was obviously offering a night of sex, most likely no strings judging from the way she'd picked him up, and that was perfect for him. He was still reeling a little from the divorce, and nothing helped the reeling quite like a sex-filled night with a gorgeous woman who looked nothing like either of his ex-wives, and who he was willing to bet he wouldn't want any further attachment after they had their fun.

"Smart man," she grinned. She stopped walking, leaning back into him slightly and moving her mouth near his ear. "I've got a much more casual dress code at my place," she husked in his ear, letting her lips brush his skin.

All the blood in his brain rushed south at that gesture. If he had questioned what she had in mind before, there was definitely no questioning what she had in mind now. And that suited him just fine. He followed her out then, watching as she easily got a cab. He found himself reflecting on how much more quickly she could get a cab than him; though he had to admit if he were a cab driver and saw her in that dress on the side of the road, he'd be pretty fast about picking her up for a fare as well.

After a rather hands on cab ride, they got out in front of her building and he could barely keep his hands to himself. He liked to touch things, she noted, and that was perfect for what she had in mind. Normally she wouldn't bring a guy back to her place so quickly, but despite not letting on to him, she did know who he was and felt she was safe doing so; besides, she was a cop after all. And it wasn't like she was going to get a hotel room when she lived a short cab ride from the hotel where the party was being held.

She hadn't let his lips touch her in the cab, the only touching she'd allowed was with his hands. But now on the way up to her apartment, she didn't make him stick to such rules and found herself being tugged back against him by his hand on her hip and his lips on her neck as she worked to unlock her door. Turning around once it opened, her eyes met his and that was all it took to spark the gasoline that had been poured on them.

Her lips were on his in a matter of seconds, her tongue pushing past the barrier and invading his mouth, claiming him as hers. His hands were everywhere all at once on his body, unable to find a focal point as he needed to touch all of her. Grabbing his shirt, she pulled him inside and moved to shut the door only to find that he used her body to close it as he pushed her against it, his mouth moving along her jaw to her neck.

The soft gasp she made as his teeth found a particularly sensitive spot on her neck, just below her ear made him smirk smugly. Oh, he has an ego, she somehow found the ability to think. Though, that wasn't overly surprising; all men have egos. Her hand moved to the front of his pants, and she hooked a finger through a belt loop, tugging him back toward her bedroom. Once there, she ran her hand from his pants up to his chest and gave him a firm shove onto her bed.

He was so shocked by her move that he missed her slip her dress off entirely. Before he realized it, she was straddling him on her bed in nothing but her underwear, which he wasn't even sure the small fabric she was wearing could be counted as such. Seeing her practically naked above him, he knew he was done; he was helpless and didn't mind one bit.

His hands slid along her thighs to her hips, fingers playfully dancing, teasing just under the edge of the remaining fabric, smirking as he noticed her wiggle. She likes that, he realized. And then he saw it, peeking out from the top of her underwear, just on her hipbone: a sexy tattoo. With another smirk, he quickly flipped her to her back and shifted so he could have a better look, tugging her underwear down in the process. His fingers and then his tongue traced the outline, and she couldn't help the way her hips rolled toward the feel of his tongue on her skin. "Fuck…Rick…" she breathed. She likes that too, he noted.

After allowing herself a few moments to enjoy his tongue on her skin with her eyes closed, she opened them again, giving him a firm tug as she shifted to her knees on the mattress. "I told you the dress code is casual," she breathed, having his shirt unbuttoned in record time.

Once again she had caught him off guard, and he found his shirt off his shoulders and hitting the wall before he had a chance to blink. Damn…she was sexy. He growled lowly as he found himself underneath her again, her mouth assaulting his chest, her teeth grazing and biting his skin. She seem unfazed by any marks that might get left behind, especially when she felt the way he reacted to the gentle bite she had left on his pulse point.

He shoved her up then, and pinned her beneath him with his hips and used his hands to pin hers just beside her head, something else she typically was not a fan of letting men do to her. But she felt oddly safe with him, which was crazy since she had literally just met him, and was only able to reason it away to knowing exactly who she had in her bed. His mouth left a hot, wet trail of kisses down her chest then, tugging a nipple between his teeth none to gently. Judging from her reaction to that, he made a note that she liked that too.

His mouth continued down, nipping and licking at her skin, her navel, her tattoo again. When he shifted to nudge her thighs apart with his face, she easily freed her hand and tugged his hair to stop him. "No," she stated breathlessly, but firmly. That was more intimate than she was willing to be for a one night stand.

He searched her face to see if she'd changed her mind about the whole thing, but seeing her eyes, seemed to understand what she'd meant. He abided by her wishes and moved his mouth back to her navel and slid his now free hand down her side to her hip, slowly testing the waters to see if she'd let him touch her that way and giving her plenty of opportunity to stop him. When she didn't, he glanced at her to make sure it was fine.

Tugging her lip between her teeth, she simply shifted her hips to meet his touch. He seemingly got the message, because a moment later a low moan had escaped her lips as his finger slowly traced her, dipping into her slightly before moving back to her clit. Fuck, he's good… was the last coherent thought she had as he slowly, agonizingly worked her up to her peak with simply his thumb and a finger.

He released her other hand so that he could hold her hips, letting her move slightly to get some relief, but not so much that he wasn't still completely in control of the moment. Watching her reactions as he touched her, he couldn't help but realize how much more beautiful she was than he had initially realized. The way her chest heaved as her breath hitched, the way her lip kept being tugged between her teeth, the way her head leaned back with her eyes closed in pleasure…pleasure that he was providing her. Another few moments later and her fists were tightening in her sheets as she crashed over the edge, her moans of pleasure sending even more fire to his groin.

She kept her eyes closed, enjoying the feeling as she rode the waves of her orgasm. When she opened them a few moments later, it was her turn to be slightly surprised by the fact that his pants were now gone and he was already sheathed with a condom he must have had on him. Arching an amused eyebrow, she couldn't help the chuckle that escaped. "Guess you were looking to get lucky tonight."

He shrugged with a grin. "I'm a guy. I always have a condom in my wallet. Never know," he pointed out. Remembering her stopping his attempt to taste her earlier, he arched his eyebrow at her now. "Any requests for the main event?" He was going to enjoy it any way it happened. He wanted her to be comfortable with it so she could enjoy it too.

Oh…that's new… she thought. She'd never imagined he would be so openly willing to give her the power without her having to take it; in her experience, men typically did not do that. To be on top, she would frequently have to wrestle her way there. She shifted to reach out for him, pulling him to her for a hot kiss, that turned out to be a lot slower and deeper than she had intended for such a night. Twisting them slightly, she gave him a push back so he was flat on his back now and she was straddling him once more.

He looked up at her with wide eyes and a grin. "I get it, Nikki…you like to be in charge…" he commented appreciatively, his hands moving to her hips. "That's really, really hot…" he added in a low murmur, letting her take the lead now.

She wasn't used to this…to so easily being given control, at least not in a situation like that. Not that she frequently participated in one night stands...at least not since her 20s when she was still spiraling out of control at the death of her mother...but they tended to involve men much more anxious to reach his own sexual goals that letting her reach hers. But he seemingly had no qualms with letting her have the power. She had expected something different. Tugging her lower lip between her teeth then, she shifted so that she was slowly sliding down onto him with a low groan.

"You've got to stop doing that with your lip…you're killing me…" he pleaded with her, his fingers digging into her hips as she sheathed him inside herself.

She met his eyes and with a smirk released her lip from her teeth, only to run her tongue over it seductively.

"Nikki…" he growled lowly. That was worse, and she knew it.

She wasn't sure why, but she took pity on him then, her hands sliding to his chest to give her leverage and a sense of balance as she slowly rolled her hips with his, riding him at a pace that was making him crazy. She unintentionally tugged her lower lip between her teeth again after a few moments in focus, her movements on him becoming quicker and rougher as she worked them both up.

He couldn't help the way his hips finally bucked up against her as his control started to slip. Another few moves of her hips and he was digging his fingers hard into her hips as he came on a groan. With another couple of moves of her hips, she had followed him and dropped down onto his chest breathlessly.

It was several long moments later before both of them could breathe normally again. She slid off him and rolled onto her back with a satisfied feeling coursing through her veins. This had definitely been what she'd needed. She also knew she could never tell Lanie about this. She'd be hearing "I told you so" for months.

He shifted slightly to look at her. "So…another round? Or…" he asked after a moment. He knew it was a one night stand; it just had the feel from the moment she picked him up. He just wasn't sure how long, exactly, she wanted that one night to last.

She gave him a true smile. "It's late," she stated. "But thank you."

He nodded and pushed himself up then. "The pleasure was all mine, Nikki. Trust me. Mind if I use your bathroom?"

She shook her head an gestured in the general direction, watching his backside as he headed in the direction she had pointed. She found an oversized t-shirt she slept in occasionally and slipped it on. When he returned, she watched him dress in the dark, the only light in the room the lights from the city outside her window. She felt the need to at least walk him to the door, telling herself it was mostly because she needed to lock it behind him. Before she opened it, she surprised herself by leaning in for one last kiss. "Goodnight, Rick." She opened the door then.

"Goodnight, Nikki," he gave her a grin. And with that he was gone.

The second she realized the connection between the way the body was staged, she cursed inwardly. Fuck. Why? Why me? She had to ask herself. Why had she been so stupid to sleep with him a year ago on a whim, thinking there was no way in hell she'd see him again considering they traveled in very different circles. It was like she jinxed herself. And this...this was why she didn't do one night stands. Because now…now she was going to have to go talk to him, and though she doubted he would remember her (she figured she was just another one night stand in a long line of them to him), she definitely would know what had happened. You're a cop. And and adult. So what if you slept with him? You can handle this, she told herself.

Having tracked him down, which wasn't too hard since she was a fan and knew he had a release party that night, she walked through the crowd until she spotted him at the bar with a girl, who she'd assumed was his daughter. Somewhere she'd heard he had a kid; it was still a surprise to see him with one so...grown up.

"Richard Castle," she stated firmly, coming up behind him.

"Where would you like it?" he turned around with a smug grin, Sharpie opened, ready to sign her chest, she figured.

She held up her badge. "I'm Detective Kate Beckett. I need to ask you some questions about a murder."

He was frozen when he saw her...and then the badge...completely caught off guard. Oh shit…it's her…just...wasn't her name Nikki? he realized, remembering their night together clearly. He wasn't sure why it had never occurred to him to think she might be a cop, or that she'd be giving him a fake name, but as he reflected on their night together, he realized that her drive for control and her strength fit much better with that narrative. He remained frozen, completely caught off guard, both by seeing her again, of all people, and finding out she was here to question him about a murder. This actually might turn out interesting if he played it right.

The girl with him reached around and took the Sharpie from him with a smile. "That's new," she stated simply.

"Mr. Castle, I'm going to need you to come down to the station. I've got officers waiting downstairs to give you a ride." Because there was no way in hell she was bringing him in her car. She hoped against hope that he really did not put the pieces together of who she was, otherwise this was going to be very, very awkward. Especially because she couldn't control him, or what he said about her without tipping her hand. The headache she was getting that had started at the crime scene was beginning to grow.