AN: Oh my goodness it's been almost two months! I'm so sorry guys, I have been so incredibly busy (though that's hardly an excuse). Oh, and I also moved, so there was that.

This one's for star90 who suggested I try my hand at "Nikki Heat." I wanted so badly to get this right, so that added to the time it's taken me to finish (and I'm still not sure I've really done it justice, but we'll see).

Before you start reading, I'd like to say that i this one they say a few things they regret, so please keep reading, I hope I'm not butchering the characters. If I am, tell me so I know. I tried to make it obvious that Kate feels bad, but she says some things in the heat of an argument that shouldn't be said. So there's your warning, I guess. (Please don't let this prevent you from reading though.)

So here you go, I hope you like it. Review so I know please :)

Kate walked out of the conference room, set her mug down on her desk, and tried not to think. She wanted to go home and take a bath and definitely not think. Why had she ever thought it was a good idea to let an actress follow her around? Wasn't the writer bad enough?

She shuddered at the creepiness factor of seeing Natalie Rhoades dressed and made up as her. No, dressed and made up as Nikki, not her. That really couldn't be normal, could it? Living in a crawl space and following detectives around was one thing, but she had a wig and everything! No, that could not possibly be anywhere near normal; stalker maybe, normal, definitely not.

Go home; don't think. Kate instructed herself. But then she heard a loud thump coming from the elevator.

She had honestly thought they'd already left, had purposely waited in the conference room so she wouldn't have to see them walk out together. But the elevator must have taken longer than she'd expected.

As she turned she somehow knew what she was going to see, but when her eyes found the two of them, kissing unashamedly in the elevator, fresh shock and debilitating pain washed over her. She couldn't have looked away had her life depended on it. Judging by the way her heart felt as if it was simultaneously being crushed to dust and stabbed with an incredibly blunt knife, maybe her life did depend on her strength to look away. However, like a train wreck, the scene captured and held firm on her attention, effectively twisting the knife deeper.

And then the doors closed. Kate was left with nothing but an empty bullpen and her raging imagination. Because seeing Castle kissing Natalie Rhoades, made up like her, was surreal. Like she was watching herself kiss him, had she but the courage.

But she wasn't kissing him; he was leaving with his very own fantasy version of her. And why shouldn't he? It's not like she had given him anything, not any inkling that the feelings he so obviously had for her were reciprocated. Then again, could she really be sure what he felt? Yes, he'd asked her to accompany him to the Hamptons, and there was not way he'd actually meant just as friends, but that was months ago. There was no guarantee that those sentiments withstood his summer.

Go home; don't think. Kate repeated the mantra over and over as she packed up her things. On autopilot, she headed for the elevator, but halfway she stopped dead, spun around, and stalked off in the other direction. The stairs would definitely be less painful.

Her drive home was a blur, all thought forfeited in deference to her mantra. Not until she had gently closed her door and turned the lock did she allow the pain, anger, and though she'd never admit it, jealousy, consume her.

How could he do this? She asked herself as she flung her purse onto the couch. Why her and not me? But she knew the answer. Why Natalie? Because she was willing, and a fantasy. Why not Kate? Because of the past two and a half years she'd spent rebuffing his every advance.

"Damn it Kate!" She cursed herself aloud, forgoing any semblance of sanity she'd been grasping at as she began to argue with herself.

"So many times, turning him away, pushing him further and further so you could have your precious space." She made air quotes and screwed up her face, staring at a random point in space. Turning around, she started pacing back towards her kitchen, her argument changing direction as well.

"And him! Richard fucking Castle! I'd thought he'd changed! Thought he'd committed!" She threw her hands out in front of her, but then her anger stuttered. "Committed? Committed to what? The precinct? Nikki? Me?" She placed her hands on her counter, terror temporarily halting everything else. She wasn't ready for thoughts like that. She knew what she wanted, but admitting it, event to herself, was just too much. "You have no claim on him Kate. It's time you come to terms with that. But whose fault is that?" She shoved herself off the counter as her anger returned.

"It's not my fault, that's for damn sure! He's the one who left! Bailed on me when I'd finally decided to give in. And now?" She asked her non-existent audience on the couch. "Now he's not even trying. Honestly, Natalie was dressed up! As ME! He wasn't even interested until she put on that damn wig. Scratch that," she said, waving her hands in front of her to clean the slate as she continued pacing. "He hated her. What did he say 'Nikki is a complex character. A thinking man's cop.' Definitely not Natalie Rhoades. But then she puts on that costume and suddenly he's all over her? I thought he'd grown out of being a playboy. I guess I was wrong."

Kate flopped down onto the couch. She was still fuming, but her adrenaline had mostly burned off. She knew it wasn't fair of her to accuse him of still being the playboy he was. There was no doubt he'd changed since she first met him, otherwise she never would have even considered going to the Hamptons. No, she'd known he wasn't the same Richard Castle the moment he'd actually apologized for looking into her mother's case. He'd thrown a hundred thousand dollars off into space for her. And even after he left, he came back. Maybe it hadn't happened quite the way she'd expected, but still. And then she'd let him back into her life. That bet was a sham, she could at least admit that to herself; she had let him come back. And that meant something, didn't it?

"And damn it he should know that!" The burn of anger ignited again and she couldn't just sit there.

She knew it was stupid, but she had to go. She knew full well that no good would come of it, but her instincts, not to mention her anger and need to express it, told her she had to talk to him. No, not talk, yell. She needed to yell at him. To glare and scream and damn it she needed him to know he as being a jackass.

Kate tried not to think; thinking would only prevent her from doing what she wanted.

Find him; yell. She thought, making it her new mantra. She repeated it the entire drive to his loft. There was no guarantee that he (they?) would even be there. But it was the only place she knew to look.

In the elevator she continued reciting her mantra. Her resolve had been wavering, but then she remembered when he'd stood there and told her he'd do anything, even nothing. The memory sent pain coursing through her. That night she hadn't realized how much that meant, but she did now, finally. And the fact that he would so something like this now, after she'd allowed herself to hope they could have something, was infuriating.

Kate knocked brusquely on the door, not even caring if the neighbors, or even Martha and Alexis heard. She was very close to kicking the damn thing down when if finally opened.

He was standing there in flannel pajama pants and a light grey tee. His face turned down in confusion, but she wasn't about to let him catch her off guard, even if his casual attire was distracting her with memories of when she'd been staying with him. Early mornings with his daughter running out the door for school while she sipped her coffee and he groggily tried to force smorelettes on her. She hadn't stayed more than a few days, but they had definitely made an impression on her.

No, focus. Time to yell. Kate reminded herself before shoving her way past him.

"What the hell were you thinking?" She rounded on him as he locked the door. He stared at her and his confusion melted into guilt. For the first time she seriously wondered just how far that kiss had gone, wondered if Natalie was in the other room even now. Disgust, and still more jealousy she would never claim, boiled in her stomach at the thought. She didn't want to believe that of him, but her anger blinded her to any guilt just yet.

"Beckett, let me-" Castle started, but Kate cut him off. Listening was not on her agenda.

"Let you what, Rick?" She spat his first name at him and watched as he flinched. "Explain? I see you kissing Natalie fucking Rhoades, and you want me to let you explain? I'm not that naïve; there's nothing to explain. You're a playboy, Castle. You always have been! I don't know why I expected any different. You haven't changed a bit since I met you." Logically she still knew that wasn't true. Whether or not he had kissed, or Heaven forbid slept with Natalie, he had changed. She couldn't deny that. But she was so angry and hurt for reasons she wasn't yet ready to examine, and rationality just couldn't overcome that.

Kate drew in a ragged breath, steadying herself for what she was about to say. Again, she knew it was a lie, and would cut him deeply, but in that moment, the knowledge of the sting in her words just wouldn't prevent her from saying them. She'd released the dam of her emotions, and she refused to own up to the jealousy and longing, so pain and anger was all she had left. So she spit her words, never as refined as his, at him.

"No matter how much I hope to the contrary, you're still Richard Castle, millionaire playboy writer. Stick a pretty girl in front of you and you'll chase her, just like you did when you met me. Frankly, I'm just surprised it took you so long."

Kate stopped there, her rage expended, leaving only a tumultuous mix of pain, guilt, and a hint of desire that had been growing since she'd crossed the threshold.

Castle just stood there, apparently dumbstruck. She could see the wheels turning in his head; knew he was searching for the right words. He was always so careful with how he expressed himself. The way he found surprised her, as always.

"You have no right." His voice was calm, but she could see the fire in his eyes, and she knew his time to yell wasn't far off. "You have no right to tell me what I should or shouldn't do. No right to cast disdain upon my lifestyle. And," he was getting heated now, his face reddening slightly as his voice rose, "you have no right to tell me that I haven't changed since I met you, when we both know that is a complete lie. You and I both know, Kate, that I have changed." Though his voice was still forceful, not quite yelling but almost, when he said her name there was none of the bite she'd put into his. It was as if he reveled in the opportunity to say it, since it was so rarely afforded. Him using her first name made the guilt burn hotter alongside her melted desire. She loved it when he called her Kate, even if it was across the bullpen trying to get her to stop and talk to him, and now was no different. But she had to focus, he was still angry, and saying something important, even if it was something she didn't exactly want to hear. "I've altered my entire fucking life! All so you would so much as look at me. I've been here Kate, just waiting to deserve you, waiting to be worthy of such an amazing woman as you. And now here you are, berating me with false accusations and misconceptions."

He took a step towards her, anger pouring off him and her guilt only grew. How could this have gone so differently than she'd planned? She was supposed to yell, he was supposed to feel guilty, not the other way around. Of course, she had earned her guilt, she knew that now. Her plan to yell had been selfish and she hadn't even considered that she may not have all the information. She deserved admonition, and as Castle continued, she struggled to keep her eyes off her shoes.

"The truth is that Natalie kissed me. I was caught off guard, but as soon as I got my head back on I stopped it." Kate, who had been looking anywhere but his eyes, mostly at his lips, flicked hers to his. This wasn't what she'd been expecting to hear, an explanation maybe, but not this; fresh guilt (could she feel any guiltier?) settled in her stomach.

"That's right, Writer Boy has some self control. And then, now here's the kicker Kate, she invited me back to her hotel, but I declined. Do you know why?" He took another step closer, moving into her personal space.

She didn't want to hear why; she already knew. And to think all the things she'd said. She wanted to look away in shame, to cry at her foolishness, to do anything but meet his eye, but he wouldn't let her. He held her gaze simply with the intensity of his own. And she saw the truth in his words as he spoke, his voice softening immediately.

"Because she wasn't you. No amount of make up, clothing, or wigs would have made her you, Kate." She could tell his anger still burned hot, but it seemed to have shifted somehow. She didn't understand the look in his eyes, was that resignation? "So no, I did not go home with Natalie fucking Rhoades. And we both know I never would."

He was right. She knew him well enough now that she shouldn't have jumped to conclusions, should have trusted him.

She was speechless, could not think of a single thing to say. They both stood there, a foot away from each other, for a few seconds. He waiting for a reply, she failing to find one. Finally, Castle sighed, turned away from her, and walked into his office without even bothering to close the door behind him.

Kate didn't move for several moments, warring with herself. She was terrified and was more than tempted to run right out the door. But she couldn't stop replaying his words in her head. "Waiting to deserve you." "She wasn't you." She knew what those words could mean, and the hope that flooded her mind and heart when he'd said them would not allow her feet to walk out the door. Instead, she turned and followed him into his office.

She found him leaning against what she presumed was his bedroom door. His face was in his hands as she approached; it was obvious he didn't hear her come in. She didn't know exactly what she was doing, but for once she didn't care. She didn't want to think. Thinking would force her to look at her, their, future, and that was too much for now. She didn't want to think, she just wanted to touch him.

When she stepped up to him; he still hadn't realized she was there, so he startled when she took a wrist in each hand and pulled them away from his face. When they hung limply at his sides, she released them and moved her hands back up to cup each side of his face. Her fingers tangled themselves in his hair.

Standing on her toes so they were absolutely level, she looked him dead in the eyes, her nose a mere inch from his, and tried to convey everything she was feeling. The fear, guilt, shame, and lust pouring out of her as tears threatened to spill from where they'd welled up in her eyes. Before they could, she spoke, saying the only words she could come up with, knowing they would never be sufficient.

"I'm sorry."

His face broke then. Anger gave way to forgiveness and- No, that was too much, too fast. She couldn't handle that yet. But she knew it was there, and she couldn't deny it was probably written on her own face as well.

Kate dove at Castle, locking her lips with his. He moaned as she bit softly at his lower lip, the feel of which was sending electric heat coursing through her, pooling low and hot.

Castle's hands wound around her waist, his fingers dipping under her shirt as he pulled her closer. Their hips met and it was her turn to moan. Castle's tongue invaded her mouth, swallowing the sound.

His fingers tensed against her back and he pulled her closer still; she wasn't sure closer was possible while they still had clothes on, but she loved the sensation of his body against hers. Her hands wandered down and to his sides where she took fistfuls of his shirt as she rocked her hips against his. The delicious friction almost broke her. Releasing her grip on his shirt, she wove her hands back up to rest on his chest. She returned her attention to his mouth, tangling her tongue with his with newfound fervor.

As their mouths dueled, his fingers skimmed their way higher beneath her shirt. When his thumbs grazed over her bra she shuddered and felt Castle smile against her lips. She broke them apart and laughed into his shoulder.

"Yes." She whispered as she pulled his shirt aside to kiss his clavicle.

"Huh?" He asked, a little breathless as he pulled Kate back to look at her. She smiled.

"You were going to ask if I was sure. I am." The smile fell off her face when she saw the shock and unashamed joy sparkling in his eyes. She reached around him and turned the doorknob.

She felt him tense, catching his balance as the door swung away from him. She leaned in to bit his ear gently before whispering.

"I expect pancakes in the morning."

AN 2: Okay, tell me what you think! Please!

Goodness this is the longest one I've ever written! Yay!