Summary: Takes place after Countdown. Castle and Beckett finally talk about their undercover kiss, what it truly meant to both of them, and where they want to go from here. Spoilers for Knockdown, Setup, and Countdown.

Author's Note: I'm new to the site so this is my first Castle fic. I'm going off the promo pics for Setup and Countdown and assuming that Kate and Josh break up.

Disclaimer: Sadly, I do not own Castle or anything related to it.

Chapter 1

Kate Beckett dried the last few dishes and then flopped down on the couch to try to calm her nerves. Castle was on his way over for a night of burgers, milkshakes, and movies. It had been a stressful week. This last case had been one of the most high-stakes cases of her life, and to top it off, she and Josh had ended things a few days ago. She liked Josh. She really did. But it just was not working out. Between both of their schedules and his trip to Africa, they just never got to see each other. So when Castle had suggested that they both needed to relax this evening, she had taken him up on his offer without giving it a second thought, mainly because the thought of going home to an empty apartment was too much after the week that she had had.

It's just another evening, she told herself. Castle and I spend time together all the time. There's nothing different about tonight. However, as much as she told herself that, she knew it was not true. Kate knew she had feelings for Castle. She had known that for a while, but after the heartbreak of last summer, she had been trying to suppress them. She was afraid to act on them again, but lately Castle had been making that difficult for her. He had been nothing but sweet to her, and everything he did broke down her defenses a little bit more. There was the scholarship that he had set up in her mother's name. He had been by her side through Raglan's case. He had come over with flowers as though he had known that she needed company. And he had saved her life. Not to mention their undercover kiss that had turned into so much more. Kate's stomach knotted as the memory replayed for what seemed like the millionth time in the last month. Just the thought of it still gave her butterflies.

A knock at her door snapped her out of her fantasy. Remember, it's just another evening, she reminded herself again, trying to ignore the fact that one of the main reasons she had ended things with Josh was standing on the other side of her door.

"Hey, Castle," she said opening the door.

"Hey." He held out a Remi's bag, giving her his familiar grin. "I come bearing gifts."

She took the bag from him and stepped back. "Come on in." He shut the door behind them and tossed his jacket on the back of the couch. Kate headed to the kitchen to grab napkins and ketchup while Castle spread the burgers, fries and shakes on the coffee table. They settled on the floor with their backs against the couch and dug in, falling into a light-hearted conversation with ease. Castle filled her in on Alexis's latest college ideas and his mother's latest role, in which she was cast as a crazy aunt. They talked about the upcoming benefit for the Johanna Beckett scholarship, and touched on anything else that was not work related. As they finished their milkshakes, Kate found her nerves calming a bit. However, as they stood up to clean up the garbage and the backs of their hands brushed ever so softly, she suddenly found that her heart was racing again.

Instead of making it awkward, however, Castle simply pretended not to notice and slipped in a movie before settling back down on the floor. Kate reclaimed her seat as well, trying as hard as she could to calm her unsteady breathing and her pounding heart. They settled into companionable silence to watch the movie. At some point, they moved up to the couch, careful to leave a few inches between them. But when Beckett shivered part way through the movie, Castle automatically scooted over and put an arm around her shoulder, pulling her close. Much to his surprise, she did not protest.

When the movie finished, Kate absently reached for the remote and turned off the TV without moving from where she was snuggled up against Castle's side. She was way too comfortable.

They sat in silence for a while, minds wandering. Castle finally broke the silence "Beckett, what are we doing?" he asked.

"What do you mean?" She had a pretty good idea to what he was referring, but she wanted to make sure before jumping into this conversation.

"I mean us," he clarified. "We're cuddling on your couch late at night. A month ago, you never would have been okay with this. I'm not complaining," he added quickly.

"A month ago, I was still with Josh," Kate reminded him, sitting up straighter and sliding out from under his arm. He wished she had not moved, but Castle knew that if this conversation was headed where he thought it was, Kate would need some space.

"Yes, but things have been different between us lately," Castle said. "Don't try to deny it because I know you feel it too. Ever since…." He trailed off, but Kate knew exactly what he was thinking because she was thinking about it too.

"Look, Castle, we both know that that only happened so that we could get in the building," Kate said. "That's all it was." But even as the words came out of her mouth, she knew they were a lie.

"That's not all it was and you know it," he said gently. She opened her mouth, but stopped, unsure of what to say next. "Listen," he continued. Maybe if he guided the conversation, it would make this easier for her. "You don't have to say anything. Let me just tell you my side, okay?" When she nodded, he continued. "When you started to pull out your gun, I knew I had to stop you. As soon as you took a shot, Ryan and Esposito would have been dead. Hell, you and I probably would have been too. I was scared and I panicked, and we were pretending to be a couple anyways, so I kissed you. It was supposed to be a diversion, yes, but that wasn't the only reason I did it. It was something I'd wanted to do since the day I met you. Neither of us knew what we would find once we got inside that building, and if something happened to either one of us, I didn't want to regret never letting you know how I felt. How I feel. So I took a chance, and it was the best one I've ever taken."

Kate was speechless. The sincerity in his voice was unmistakable. His eyes met hers with an intensity she had seen only once before; that night, right before he kissed her. They sat in silence for a minute while Kate gathered her thoughts and found her voice. Castle did not say any more. He knew that she needed to process what he had said, and he was perfectly willing to wait.

Kate finally decided that after what he had just admitted, he deserved the truth as well. She took a deep breath and began. "You're right, it wasn't just for cover," she said, glancing away. His gaze was too intense for her right now. "At some point, I forgot what we were actually doing in that alley. If that guard hadn't chuckled when he did…." she left the rest unsaid, but Castle knew what she meant. "But I was with Josh, so I tried to ignore it, pretend it never happened. That way, it wouldn't feel like I'd cheated on him."

"You didn't cheat," Castle reassured her quickly. "It legitimately was for work purposes."

"I know," Kate said. "But after that night, I felt like I was cheating him. That's part of the reason we broke up. After you and I kissed, my heart just wasn't in that relationship any more, and he could tell that too."

"Kate, I'm so sorry, I never meant to get in the way of the two of you," Castle said. "I know you were happy with him, and I didn't mean to take that away from you."

"It's not your fault," Kate said, looking up to meet his eyes this time. "It was bound to happen sooner or later anyways. Josh is a good guy, and I was happy enough, but he wasn't around much. And the truth is, he was never going to be what I truly wanted." She let the silence hang, trying to decide if she should continue. She had already said a lot. More than she really wanted to, because she knew that opening herself up to Castle was risky.

"What do you want, Kate?" Castle knew he was taking a chance by asking that question. She had already admitted quite a bit, and there was a lot at stake here. But he needed to know.

"Castle…." she started to protest.

"Okay, never mind," he said quickly. "I'll go first again. I'll tell you what I want."

"Okay," Kate agreed nervously. She was not sure she was ready to hear this.

"It's probably no secret by now, but I want you, Kate. I have since the day we met."

"Castle…."

"No, let me explain." He knew exactly what she was thinking. "I should have worded that differently. At first I just wanted you for one night. You know that. You turned me down, and I took that as a challenge. Once you said no, I knew I just had to have you. But once I got to know you, I realized that you turning me down was the best thing that ever happened, because you are worth so much more than a one night stand. If that was all we had had, I never would have gotten to know you. The real you. And now that I do, I can't imagine my life without you in it, Kate."

He was dropping bombshells right and left tonight, although now that Kate thought about it, most of this should not have been so surprising. He had been anything but discrete about his feelings for her, but she had always ignored the signs. She knew Castle's history with commitment, or lack thereof, and it was not something she had ever wanted to be a part of. You almost came clean last May, she reminded herself. You didn't seem to have a problem with it then. Of course that had also been before he walked out on her with Gina on his arm. That wasn't entirely his fault, the voice in her head scolded her. He thought you were with Tom. She knew that was true, but the memory still stung.

Castle waited quietly again, glancing around the room in an effort to give Kate her space. When she spoke again, it was in a tone Castle had never heard before. Her voice was steady, but there was the smallest trace of fear in it. "I'm scared, Castle," she said, eyes fixed on her hands. "My heart wasn't in it with Josh because in all the times he kissed me, it never felt like it did with you. Even undercover, I was blown away." She could not believe she was admitting this, but she continued before she lost her nerve. "Being with you has crossed my mind more and more often lately, Castle. But I'm scared. We have so much at stake." The last sentence came out as barely more than a whisper. "What if it goes wrong?"

Castle let out the breath he did not realize he had been holding. Coming from Kate, that was a huge admission, and he knew that. But he had to make her believe that he was serious. And that he was just as scared as she was. He decided to start with the latter, knowing it was the less touchy of the two subjects.

"Someone once told me that 'love is giving someone the ability to break your heart, and trusting them not to,'" Castle recited. "Don't take that to mean anything more right now, please, it's just a quote," he clarified, not wanting to freak her out any more than he obviously already had. "But it's a pretty good one, because it sums it up pretty well."

Kate looked up at him. "I never thought of it that way," she admitted. "It makes it sound even scarier."

"They're powerful words," Castle agreed. "It makes you realize just how much power you can have over someone else." He paused. "And how much they can have over you."

She contemplated that for a moment. "So what are you saying?"

"I'm saying that I'm afraid too," Castle explained. He paused, waiting for her to look up at him. When she did, he continued. "In my opinion, willingly giving somebody else that much power over you is the scariest thing you ever have to do. It takes more trust than most people have." He swallowed, then reached out and gently took hold of Kate's right hand. She glanced down but did not pull away. "I don't know how it happened, I don't even know when, Kate, but you already have my heart," he admitted. "I didn't even have a chance to decide whether to trust you with it because you had it before I even realized it. And that thought is absolutely terrifying." Kate had looked away at some point, but Castle squeezed her hand, making her meet his eyes again. "But I'm choosing to trust you, because it's less scary that way."

"I want to trust you too, Castle. I really do," she began, trying to figure out the best way to say this.

He saved her the trouble by reading her mind yet again. "But I have a history and it makes it difficult, right?" he asked.

She nodded. "I'm sorry, Castle, I wish it didn't matter, but it does."

"I know," he said understandingly. "And if I was in your position, I'd feel the same way. Sure, I'm older now, I make better decisions now than I used to. And you're different," he paused. "But I know that telling you all of this probably won't help, because my reputation speaks for itself."

"What do you mean, I'm different?" Kate asked, trying to decide whether she should be taken aback by his comment.

"I mean you're not like anyone else I've ever met. And I've also never been friends with someone before I had a relationship with them. Or partners. You said so yourself, there's a lot at stake here. If this goes wrong, we lose a close friendship and a solid partnership. But if it doesn't…." Castle trailed off. He did not need to say the rest. It was something both of them had spent a lot of time thinking about lately.

Kate opened her mouth to ask a question, but stopped before anything came out.

"What?" Castle asked.

"No, never mind," Kate said.

But Castle would not let it go. Not now. She needed to know that she could trust him "No, what?" he asked again. "Kate, you can ask me anything you want if it will make this easier for you. Even if it hurts me." He squeezed her hand again in encouragement.

She could tell he was serious, and even though his potential answer scared her, she took the plunge. "Why me?" she asked, her voice wavering.

"What?" Castle was confused.

"Why me?" she asked again. "You could have half the women in New York City. You could do so much better. So why pick me?"

The question took Castle by surprise. It was something he thought about every day, every time she revealed a new facet of herself, but he never thought he would have to explain it. He was unsure of what to say, so he started at the beginning of her question. "Sure, I have lots of choices," he said. "Women throw themselves at me at every public event I go to. They do that because they're interested in my fame and my money. Even Meredith and Gina….that's what they were in it for too. But you….you've never wanted that. Even from that first day, when you dragged me into the interrogation room, you treated me like a normal person. Every day, you remind me who I really am, underneath the public façade I put on in order to sell more books. You ground me, remind me what's real, what truly matters. I'm a better person when I'm with you, Kate." He took a breath and continued, changing the subject slightly. "Then there's you. You have a tremendous amount of integrity. You're dedicated and passionate, and you put every ounce of that into everything you do. You're intelligent and determined, which is why you're so good at catching killers. But at the same time, you're compassionate and empathetic, which is why you're so good with the victims. You're fiery and sassy, which keeps me on my toes. It's a rare combination, Kate, and you still amaze me with those qualities every day. Plus, you get along so well with Alexis. She looks up to you and trusts you enough to confide in you." Kate had looked away in an effort to fight back tears. Castle reached out with his finger and gently rotated her face back to meet his eyes. "Not to mention the fact that you are gorgeous." He ran his finger gently down her cheek as he spoke. "Especially your eyes. They're intoxicating, Kate. I could get lost in them for hours." He let his hand drop, but held her gaze. "How could I ever do better than that?"

At this, Kate lost the battle with her tears, and a couple spilled down her cheek. "Kate, why are you…." Castle reached out and gently thumbed the tears away.

She looked away again. "No one has ever said anything like that to me before," she said softly.

"Look at me," he said gently, taking her other hand. She met his eyes through her tears. "I meant every word, Kate."

"I….I….I don't even know what to say, Rick," she managed. Any defenses she had left were completely gone now. She was completely vulnerable, and she knew it. It still scared her, being this open in front of him, but everything he had just said had lessened some of the fear.

"You don't have to say anything," he said softly, gently wiping another tear from her cheek. He let go of her hands. "I've said a lot tonight, and I understand if you need some time and space to think about things. If you want me to head home now, I will. Whatever comes of this, I want you to be comfortable with your decision. I don't want to pressure you into anything. If we're going to do this, we're going to do this right, because I don't want to lose you, Kate."

"Thank you," she said. It was all she could manage to squeeze past the lump in her throat. She knew it was up to her, and while it was an enormous decision, she appreciated that he was letting her have her space. She already had a pretty good idea what she was going to do. There was no way she could continue to deny her feelings, especially not after tonight. She had never felt this way about anyone before, not this strongly, which was why this was so terrifying. But knowing that he felt the same way had eased her fears a bit. And after hearing what he thought of her….the emotion in his voice was unmistakable, and her eyes filled with tears again as she thought about it.

They sat in silence for a few minutes before Castle started to get up. "Don't," Kate said, grabbing his hand. "Stay for now. Please?"

"I don't think that would be good," Castle said, standing up and removing his hand from hers. In all the times he had imagined her asking him this, he never thought he would be turning the offer down. But right now, as much as he wanted to stay, he knew they both needed space.

"Please?" She was more tentative this time, and he wondered if she was doubting her decision to ask.

"Why?" Castle asked, sitting back down.

"Because I want you here," Kate answered. "Tonight has been overwhelming, to say the least, especially after the exhausting week that we've had. But when I'm with you, I don't feel so stressed. That's one of my favorite things about you, Rick, is that you always know how to make me feel better. There's a million things going through my head, and yes, I need to think about stuff. But I can do that better with you here, because I'll be more relaxed if I know I'm not going to be alone with everything." This time, she took his hand. "Please? I just want your presence."

"All right," Castle agreed. "I'll stay for now." He leaned back on the couch, away from her, but he left his hand in hers. Beckett was staring at the coffee table, and although Castle could usually read her, he realized that at the moment, he had no clue what was going through her mind.

When she finally looked up at him, she was smiling. "What?" he asked.

"You," she said simply. "I was just thinking back to when we first met, and how much you annoyed me by acting like a ten-year-old. I always just rolled my eyes. Now when you do that, it makes me want to laugh at you and smack you simultaneously." They both laughed, which lightened the serious mood that had taken over. "I never used to joke around at work. I haven't been this open and carefree since my mom died, and I don't think that change would have happened without you. And I don't know how I would have made it through these last few weeks without you." She leaned into him, resting her head against his shoulder. "I guess what I really want to say is 'thank you.'"

"For what?" Castle asked.

"For everything," she replied. "For being you. For saying ridiculous things just to get me to smile when I'm having a bad day. For being by my side even when I say I don't want you to be. For being here, now."

"You're welcome," he said, wrapping an arm around her shoulders. She snuggled into him and leaned her head against the side of his chest. He rested his cheek on the top of her head, and they sat there in comfortable silence, relishing this new facet to their relationship.

Some time later, Castle awoke with a kink in his neck. Blinking, he suddenly became aware of the fact that he was still on Kate's couch, and she was sleeping against him. As he lifted his head, the movement awoke Kate as well, and she looked up at him.

"Sorry," he mumbled, glancing at the clock. They had apparently been out for about an hour.

"It's fine," she said. "Actually, I was pretty comfy."

Castle's laugh turned into a yawn, and Kate reluctantly uncurled herself from under his arm. "Looks like someone's ready for bed," she said, yawning as well.

"Yeah, I should really go now. It's after one. Alexis and mother are probably worried." He stood up and grabbed his jacket from the back of the couch. He put it on as he headed to the door, and Kate stood up to follow him. He opened the door and turned in the entryway, his body silhouetted against the lights in the hallway.

Before Castle could figure out the most appropriate thing to say, Kate reached out and took both of his hands. "Thank you for staying, Rick," she said.

"You're welcome," he said, smiling warmly. He wanted to ask about her plans for the rest of the weekend, but he knew that it was up to her now. He had finally had the chance to tell her his true feelings and now he was willing to wait for as long as she needed.

He squeezed her hands and was about to let go when she leaned toward him, pulling him closer as she did so. Hardly daring to believe what was happening, he leaned in and closed his eyes. The moment her lips met his, the whole world disappeared. The kiss did not last long, and it was not passionate and frantic like their undercover one had been, but it was full of emotion. Tenderness, affection, love.

When Kate pulled away, Castle squeezed her hands tighter in an effort to stay standing. "Wow," he breathed, searching her face for signs that she felt the same. She looked breathless as well, and he smiled, trying to regain his grasp on reality.

"Good night, Rick," she said, grinning at the effect she had on him.

"Good night, Kate," he said. With one final squeeze of her hands, he turned and headed for home, knowing that he would have sweet dreams tonight.