A/N: thank you SO MUCH for all the love you've given me on this story, I'm glad you're all liking it and I'll try and keep updating as much as possible, so here's chapter 3!

What was he doing here? They had a deal!

Marching up to the man she thought she'd never have to see again except on a book cover, Kate Beckett demanded to know what Richard Castle thought he was doing. "What are you doing here?" She hissed, dragging him into the empty break room and slamming the door behind her.

"Ooo, you're hot when you get angry." He said, a smirk on his face. "Dragged me in here for round three have you? Though technically if you add up all the times, this would be round six.."

"Richard Castle don't you dare!" She exclaimed, looking to check no one was trying to listen in on their conversation. "I want to know what you are doing here. We had a deal, remember?!"

"What I do remember," he began, "is you using your mouth for something a hell of a lot more enjoyable than shouting at me last night. Multiple times, actually. Think we could go again?"

She was seething now. Completely and utterly infuriated with the unstoppable man stood in front of her. "Stop it. Just stop. You need to go. Home. Now." She was close to breaking point, she wasn't sure how much longer she could put up with him before she pulled out her gun.

"I'm not going anywhere except wherever you're going." He replied. "The Captain told you didn't he? You're the inspiration for my next set of novels. I wrote four chapters just in the library yesterday, before you arrested me! Oh my publisher is going to love it!"

"I don't give a flying crap about your publisher. You can't follow me around, I go to crime scenes. Real ones, not ones where you can rewrite the ending. There are dead bodies. Again, real ones - actual people have been actually murdered and it's my job to find out who did it. I don't need an annoying puppy tagging along!" She said. She had to stop him from doing this somehow. "And, how could you show up here after our deal? You even left a note about it this morning!" She asked.

"Well, you see I was doing a little thinking." Castle started to say.

"Didn't hurt yourself did you?" Beckett muttered. Looking up and smiling sweetly at him she said "please, carry on."

"Yes, anyway, I was thinking - it happens occasionally I'll have you know and I came to the conclusion that you broke the deal first, so technically it was void and I could show up here and shadow you."

Oh she couldn't wait to hear this. "What do you mean, I broke the deal first? I'd love to hear how you came to that conclusion. We agreed to go for a drink and then I never had to see you again!" Or something like that, anyway.

"Ah, but you're missing the finer points - something I wouldn't have thought a detective would do?" This earned him a disapproving glance from Beckett. "Anyway, back to the deal. Yes - we agreed one drink but you weren't coming back to mine to 'talk' and then we never had to see each other again." He could tell by he look in her eyes that she might have just figured out where she broke the deal. She was a stubborn women though, something he admired about her, and she wasn't going to go down without a fight.

"Your point?" She asked.

"My point, is that we agreed on one drink - you had three. So that's the first place you broke the deal. Pretty early actually, never would have thought you'd back down so easily.." He tailed off, lost in his own thoughts.

She brought him back to reality with a sharp "that all you got Castle? 'Cause I don't think it'd stand up in a court of law, therefore the deal wasn't broken and you. Shouldn't. Be here!"

God she was sexy when she was angry. What he wouldn't give to push her against the door and kiss her senseless, that'd shut her up.. But she was angry and also carrying a gun so probably not the cleverest of ideas.. "Ah, but you see, you also said you weren't coming back to mine..ah, let me finish" he said as she opened her mouth to interrupt. "I know technically you didn't come back to mine," you came as I called you mine though..Castle decided it was best not to bring that up right now, especially with the look on her face and the whole gun thing and continued trying to show her how she broke the deal. "But, we went back to yours. Together. And don't even think about denying that if we were closer to mine, we still would have gone back to your because we wouldn't. The only reason we went to mine and not yours is because you couldn't wait to get me naked again. Not that I'm complaining or anything. Oh no, you naked is something else entirely, I mean-"

"Castle!" She almost shouted. "Drop it! Last night was a mistake, one that will categorically not be happening again!" She said in defeat.

"You know, a mistake is something that's misguided or wrong. You can't stand there and tell me that you and me together isn't electric, Kate." He moved closer to her and lowered his voice, "oh no, we are incredible together and you can't deny that."

Pausing for a moment, Kate tried to even out her breathing. Having him so close to her was so not helping the situation. "Okay..well perhaps not a mistake.." He was right, they were incredible together. "But it shouldn't have happened, just like that night ten years ago."

Castle smiled at getting her to change her mind and not call it a mistake. "Hmm, well you seem to be making a little habit of doing things you shouldn't don't you..so, does this mean I can follow you?" He asked hopefully.

Beckett couldn't see that she had any other choice other than to let him. "Fine, but the second you mess something up, you're out. Okay?" She wasn't going to have him screwing up her crime scenes.

"Fine. I'll do exactly as you tell me and I won't touch a thing." Except maybe you..

Beckett found that hard to believe.

It was the end of another day at the precinct and another successful case laid to rest. It was the nanny today that had been killed. Castle had been surprisingly helpful, not that Beckett would willingly admit it.

"So, Detective," Castle said as they were packing up to head out. "Want to grab a drink before going home?"

Beckett narrowed her eyes at him. "I don't think so, somehow." She said, remembering how 'getting a drink' had ended up the last two times.

"A walk then?" Castle suggested.

Beckett thought for a moment. What harm could a walk do? She could just take the scenic route home. "Okay fine, I could do with the fresh air anyway."

"This is New York, there's no such thing as fresh air."

"Oh you know what I mean Castle." Beckett said, walking towards the lift.

"So," Castle said on their walk through Central Park, "I'm guessing you don't want to tell me why you're a cop and not a lawyer, but why did you give up the modelling? You were pretty successful from what I read."

"It wasn't for me, I wanted to do - wait, what do you mean from what you read? Richard Castle did you research me?!"

"I, uh..I um yeah. I did. Look, after that night at the party I didn't know why you'd just left and you were different..I wanted to know more about you. So I did a little digging..Modern Fashion, hey? They're pretty big." He said.

"Yeah they are and I loved it when I was doing it, I really did. But it wasn't where my heart was..no, I was going to become a lawyer and then when-" she broke off, almost saying too much.

Surprisingly, Castle didn't push for more information about her mother. "When did you quit?"

"That night actually. I'd been at a shoot all day and it was my last one. No one knew at that point, I hadn't even told my parents." She paused, thinking that her mother never found out she quit the modelling and that she was now a Homicide Detective with the NYPD. But then, if her mother was still here she wouldn't be a cop. I hope you're proud of me, mom. She thought to herself. "But I was going to that stupid party - oh my god, I'm so sorry I didn't think.."

He smiled at her. "Don't worry about it, I'm not a huge fan of them myself sometimes."

"Anyway..yeah, after the party I was planning on telling Matilda that I was done." She finished.

"Planning? You never told her?" He questioned.

"Well, yeah she found out, just took a while." She said.

Castle hadn't known Kate Beckett very long but he could tell she wasn't someone who let people in very easily, and he wasn't going to push her away even more now. "So tell me about your job. Who you work with. You seem to get on well with Lanie?"

Beckett was glad for the change of subject. "Lanie's great, she's my best friend. We get on so well and she's so much fun to be around..you'll figure that out soon enough."

Castle smiled. She probably didn't realise, but if he was going to get to figure out how fun Lanie was, she was suggesting he'd be around for a while.

"You know Castle, when you're not being a jackass you're actually ok. It's nice to see this side of you." They'd stopped now, sitting on a nearby bench.

He was close. Too close. "Castle, no. Don't do this.." She looked into his eyes and then her gaze involuntarily flicked to his lips and back up to his eyes.

Closing the gap, Castle planted his lips on Kates. Soft, so soft..he couldn't help himself. Just as he pushed the tip of his tongue through her lips, she pushed him away and stood up.

"No Castle, we aren't doing this! Jesus, just when I start to think you're okay, the jackass comes back out again!" She storms off, heading in the direction of her apartment.

"Beckett!" He calls after her. "Kate, wait, I'm sorry! He catches up to her, trying to apologise for what he's done.

She doesn't stop, so he matches her pace. "No Castle, you aren't sorry. You're just sorry I didn't kiss you back." Realising he was still following her, she said "what, are you stalking me now? Do you want me to arrest you on harassment charges?"

He briefly contemplated making a wise ass remark about how hot it'd be if she used her handcuffs on him but thought better of it. Now wasn't really the time. "Kate stop." She didn't, so neither did he. "Look you can say all you want that we can't do this but that doesn't mean you don't want to. You want me, I know you do."

He was right, god she wanted him more than she'd ever wanted anyone, but she wasn't letting him know that. "Castle, leave me alone!" She just wanted to get home and away from him.

"I'm not giving up Kate, not until you admit that you want this as much as I do."

"What, and then you'd just go away?" God please say yes.

"No, then I'd drag you up to your apartment and make sure you really knew why you wanted me." He replied with a cocky grin.

"So, how do I get you to leave me alone?" She asked, they'd got to her apartment building now and she didn't really want him in there.

"You don't." He pushed her against the wall and kissed her roughly. She tried to stop him, but eventually gave in, kissing him back with as much passion.

She pulled away. "Castle, no! This can't happen!"

Oh god, not again. He thought he'd convinced her.

She went up the stairs to her apartment, annoyed that he was still following her. "Castle, which part of no don't you understand?!"

Leaning in close, he met her eyes, just inches apart from him now. "Kate, tell me you don't want this and I'll stop, I swear. But I know you want me, this, us."

She wanted to say no. God she really did. But she couldn't. Dragging him into her apartment she all but attacked him. Lips and tongues battling for control, she said "don't say a word Castle, not a freaking word. I can't stand you at the moment and I wish I didn't want this but I do. I wish I could say no but I can't." And with that, she pulled him into her bedroom, shutting the door behind.

A couple of hours later and Kate was sat in her lounge whilst Richard Castle was asleep in her bed. Again. She couldn't sleep. It was only 10pm anyway. Their sex had been angry...rough. No murmured affections or endearments, just straightforward sex.

All of a sudden, there was a loud knock on her front door. Who's that? She wondered. Getting up, she walked over to the door and opened it, seeing Lanie on the other side.

"Lanie! What are you doing here?" Kate asked.

"We planned on me coming over remember? Sorry I'm a bit late, got caught up in autopsy files..what's wrong? Did you forget I was coming over?" Lanie asked with a frown.

"I..no, no of course not. It's just I'm not feeling that great..sorry, I forgot to let you know.." Kate trailed off seeing Lanie's gaze disappear over Kate's shoulder.

Turning to see what she was looking at, she could have killed him. "Uh Kate, do you mind if I take a show-" he stopped, noticing Lanie for the first time. "Oh." Was all he could say.

This could not be happening! Kate thought. How was she supposed to explain the fact that Richard Castle was emerging from her bedroom wearing nothing but a pair of boxers and asking to use her shower?

Lanie broke the silence. "Well. I can see why you didn't ring me.."

A/N: slightly shorter chapter this time, hope it's still okay! Please let me know what you think, your reviews so far have been amazing and I can't believe people are actually liking these ideas I come up with! So yeah, reviews make me very happy :)

I've started another multi-chapter fic too, called A familiar face, so feel free to check that out and review too ;)