This story picks up sometime after the end of Season 3. Each chapter will specifically deal with an "evolution" in the relationship between Beckett and Castle.

Chapter 1: Whatever You Need

She knows something is wrong. From the time they left the hospital, Castle and Josh have been sitting on either side of her taking their turns between glaring at each other and checking on her to make sure she isn't in too much pain. She wishes she could get one of them to tell her what's going on, but every time she's asked, they shrug it off and change the subject.

It hasn't escaped Kate's attention that her boyfriend and her partner don't get along. In the handful of times that they've met, there has been an animosity between them that she didn't think was warranted. But now? Now that animosity is amplified, and she's beyond happy that they've finally reached their destination, even if it means that everything could come crashing down around her any minute now.

The boys fight over who is going to carry her bags, and she's within a second of taking them from her hands before they finally decide to split the load. Considering she's the one who is injured and in need of care, neither one seems to be paying much attention to her. Their need to one-up the other is frustrating, more so because she has no idea why they're being so hostile to each other than because they're not worrying about her. She isn't naïve enough to believe that this lack of attention toward her and her condition is a trend that is going to continue, not when her boyfriend is a surgeon and her partner is an over-protective man-child who just spent almost a complete week at her side just to make sure she wasn't alone.

They go up the elevator and walk down the hall, and Kate takes note of the fact that Castle is leading the way and Josh is walking a couple steps behind her. Castle stops at the end of the hallway, expertly turning the key and entering his loft. Kate follows a short distance behind, but Josh takes hold of her wrist as she crosses the threshold, causing her to turn and see the pained expression that has taken hold of his face.

"How can you be so calm about this?"

She takes in his words, deciphering what exactly he means by his question. "Why wouldn't I be? I've stayed here before."

His eyes dart into the loft, checking for Castle's location, before he takes a deep breath and steps closer to her. "That was before. Things are…different now," he whispers, making sure her shadow doesn't overhear.

She agrees, but doesn't share the revelation with him. She is once again reminded of how many pieces of her she hasn't shared with Josh. He doesn't know anything about her mother's murder or how deep all this goes for her. To him, her being shot at Roy's funeral was a random act of violence, not a carefully orchestrated plot by the same people responsible for her mother's death as a means of getting Kate out of the way.

"One thing that hasn't changed, though, is that Castle is in a position to help me heal. I won't have to climb stairs and he can be around in case I need help."

Josh opens his mouth as if to retort, and she thinks he is about to argue that he could help, too. But the words die before they are spoken. He's frustrated with the whole situation, and she finds herself torn because she knows that she can't keep him around much longer without opening up to him about why everything is the way it is. And frankly, she doesn't know if she can do it. She doesn't know if she wants to. Sharing her deep, dark secrets was difficult enough the first time.

"I don't trust him," he finally says. They've finally found their way into the loft, where he sets her bags down next to the couch. His tone of voice has a defeated sound to it.

"You don't have to. I trust him—with my life, I might add." It's not enough to kill his concerns about the whole situation, but he seems to relax a little. "Do you trust me?" She tries not to flinch at her own question, because if he knew the thoughts running through her mind, he wouldn't trust her. At least, not when it comes to this.

"What? Kate, I—" he sputters out, caught off guard by her question. "Why would you even think that I don't trust you?"

She looks away, not wanting to continue this direction with him right now. "Listen, just try to remember that the playboy writer act is just that…an act. This isn't a bachelor pad, Josh," she says, gesturing to the loft they're standing in the middle of. "He lives here with his teenage daughter and his mother, for God's sake. He leaves in the middle of cases to attend parent meetings at Alexis's school and have movie nights with her."

Josh starts to walk away from her, glancing over the loft and seeing the evidence of her words. "Kate, he…" His words are strained, and he looks like he's having trouble voicing his concerns.

Castle chooses that moment to enter from his office, brushing his hands off and breaking the tension in the room with only his smile. "Everything's ready for you, Beckett. I can take your bags in for you if you'd like."

Josh straightens, taking the bags himself walks toward Castle. "I got it, Castle," he says as he walks toward him. "You and I need to talk."

Kate takes a deep breath, having an idea what is about to happen in the next room. The detective in her is dying to know what they're talking about, and if she can't get them to tell her then she's just going to have to go about it another way. She finds a seat as close to the office as possible, hoping to find out why this animosity is raging between them.

"I swear, Castle. If I hear a single word about you…"

"Thank you for the word of warning, Doctor. I just want her to get better. That's my one and only objective here. Nothing more, nothing less."

Castle's words are heartfelt, and she's happy to notice the absence of any sarcasm in his voice.

"Don't think for a minute that I'm going to bow out and just let you have her. You're not the only one who loves her."

"I know that." His voice is softer, and Kate instantly feels the tears forming in her eyes. "And it's because of that knowledge that I'm doing this. I'll be whatever Kate needs me to be, and right now she needs her friend and partner. Anything more will be up to her."

"You really think I'm supposed to believe that you won't use this living arrangement to your advantage?"

"Frankly, I don't care what you think."

"You're a jackass, Castle."

"Coming from you, I'll take that as a compliment."

Kate hears the door to the bedroom open, and she moves over to the couch in hopes that they won't realize she was listening to the whole conversation. She stands too quickly though, and has to hiss through the pain that shoots through her abdomen. It subsides as she settles onto the couch, and she takes a deep breath just as the two men re-enter the living room from the office.

The anger she heard in both their voices mere minutes ago is gone, and they are back to being amicable for her benefit. She doesn't know why, but it makes her feel guilty.

"I have to go," Josh says as he sits down on the couch next to her, "but don't hesitate to call if you need anything." His eyes dart toward Castle, who looks away almost immediately. Josh's eyes return to her and he tries to muster a smile for her benefit. "I'll see you in a couple days."

"Come anytime," Castle says, this time with every bit of sarcasm he owns. He waves and smiles, but drops the act the minute he hears the door shut. He looks at her briefly and then retreats into his bedroom. He's in there long enough for her to consider getting up to find out what the hell is going on. When he comes out, he plops down into the chair across from the couch, but doesn't talk or even look at her.

"Castle?" She chances talking to him, because she knows if she was in his position, she'd just want to be left alone.

"Yeah?" He doesn't look at her, instead continuing to stare at the ceiling.

"I just wanted to remind you that my hearing is still fine, maybe even exceptionally good. That and the door to both your bedroom and the office were still open."

He finally looks at her and cracks a small smile, one she's surprised she's so happy to see. "Really? Because I was sure it was because you were perched right outside the door the whole time—well, most of the time—trying to find out why we were having a pissing contest."

"Are you going to tell me or do I have to threaten you with bodily harm?"

"Threaten all you like. Just remember that I am the keeper of your pain medication. Any pain you might possibly inflict would be quick, but mine would last longer."

"Castle…"

"Do we have to do this now?"

His words send a jolt to her chest and she takes into account what he must have endured after she was shot. Truthfully, she's not sure she wants to do 'this' now—whatever 'this' is. What she does know is that she's going to be living with him for at least the next month and that it's going to be hell if they don't get some things out in the open right away.

They haven't really talked of anything of consequence since her shooting. He spent a great deal of time at the hospital, but most of the time was spent playing board games on her bed or talking about books. She distinctly remembers the looks though, and the way they told each other without speaking that their relationship had changed in some way.

She's no longer in the hospital, though. And really, why not now? She has no problem admitting that more than anything, she wants to know why Castle and Josh looked like they wanted to kill each other. "I don't think we're doing ourselves any favors by putting it off any longer," she tells him matter-of-factly, making sure he sees the seriousness in her expression as well as her words.

He stands, stretching and running his hands over his face as he walks the few steps to the opposite end of the couch. He gently lifts her legs and sits down, resting her legs in his lap as he sits and turns his body enough to look at her directly.

"Okay," he starts. "First things first. I'm sorry."

"Excuse me?" His apology surprises her, and she's not sure why he would choose to start that way.

"That day, in your apartment. I said some things—"

"If that's where we're going, then I'm sorry, too. I didn't mean it, Castle. And to be fair, you were right about some things." She pauses, not sure she wants to admit the next part, but she presses forward in the name of honesty. "Most of it, actually."

Castle hangs his head, and for a moment she's surprised that he isn't gloating that he was right.

"Do I want to know what part I wasn't right about?"

Shit, she thinks, and realizes where his mind has gone. "It's complicated, Castle."

"He thinks I'm trying to make a move on you."

"Are you?"

"Right now? No."

"Are you planning to in the foreseeable future?"

"That's up to you."

"Castle…" She doesn't use an admonishing tone, but one that warns him against the direction in which they're heading.

"I know you heard me tell him this, but I'll repeat it for your benefit. You're with Josh, and for as long as you're with him, I will make no forward advances. I'll be whatever you need me to be, Kate. Partner, friend, any, all, or none of the above."

His words warm her heart, and she sees a side of him she's pretty sure she's only seen one other time before now. And considering that her blood was pouring from her body the first time, this time gives her the chance to really take in what he's saying. "You'd do that for me?"

"Of course I would, Kate. I…"

"Please, don't," she cuts in, stopping him from voicing his admission. Her hands become preoccupied with the hem of the blanket, twisting and turning it as she struggles for the words that won't hurt his feelings. "I know. I remember."

"You do?"

"Yes. I'm just not ready to hear you say it again. At least, not right now." She can't look him in the eye, and she can tell that he's disappointed. "You still haven't told me why you were having a—what did you call it, a pissing contest—with my boyfriend."

"Nor do I intend to."

"Come on, Castle." He was frustrating her. Since when did Castle become so noble? "I know you want to tell me."

"Maybe," he told her softly, chancing a glance in her direction. "But your Jedi mind tricks don't work on me, Detective. You want to know why I'm so angry with him? Ask him yourself."

She doesn't respond, as much as she wants to, and the silence stretches on and brings a different kind of tension into the room. His last words were clipped and told her loud and clear that he was done discussing the matter.

"Rick?" she tries, her voice softer and more tentative than she thinks she's ever used toward him.

"Yeah?"

He can't look at her, but she figures that she'll take what she can get right now. She barrels forward, the words coming out like a jumble of thoughts. "I'm sorry. I just…there's a whole period of the last few weeks that I don't remember, or can't possible know about, and that's difficult for me. Knowing that you, well, just knowing is going to take some getting used to."

"Why are you apologizing for that?" His hands have started gently massaging her toes, even as his eyes stay fixed on her.

"You're being incredibly noble about this whole situation," she states simply, remembering her thought from earlier.

"If I'm going to win, Kate, I intend to win fair and square. If I cheat or take short cuts, then it cheapens the reward."

"Good point." Her words are soft, and she hopes that he caught the whisper of a smile on her face as she says them. She wants to torture him and force the reason for his attitude toward Josh out of him, but she knows now from his words and his actions that it wouldn't do any good. What she does know is that whatever it is, Josh probably was the instigator. Castle's need to be noble about the whole situation probably means that telling her would implant a negative image of Josh in her eyes before she even got his side of the story.

She also figures out quickly that Castle knows that she'll work the why of his non-sharing out on her own. He's worked with her for three years and knows the types of clues she picks up on easily. This one isn't difficult to figure out. And when it comes back to him—which it will—he can easily deny saying anything to her about what happened. Whatever it is. Because she still has no idea what was said or done to cause them to be so nice to each other in front of her that it was painful to watch.

The silence is broken some time later when Castle shifts at the other end of the couch and she is jostled out of her thoughts. He mumbles a "sorry" and watches her closely for a minute, presumably measuring her level of discomfort.

"Castle, could you help me into the bedroom? I think I could use a nap."

He's up in an instant, offering her his hands for support. "Are you OK?"

Kate stands and tries to smile from the considerable, but tolerable, pain. "Getting up is more difficult than sitting down. And I've moved around more today than usual."

Castle follows closely behind her, only touching her arm when she sits on the bed and makes a face when the pain comes back. "Do you need a pain pill?"

"No, it's going away already."

He sits down on the edge of the bed, his face serious. "Are you sure? I'm not going to come back in here in 15 minutes to find you doubled over in pain because you couldn't admit to me how much it hurt?"

"No," she says simply, her hand reaching to the top of his knee as she shifts in an effort to get more comfortable. "It was just a short stab of pain. Tomorrow morning is when you get to deal with me being bitchy because I'm in pain."

"If you say so."

"I say so."

He smiles, squeezing her hand before letting go and walking toward the door. "Just yell if you need help getting up. I'll be in the office writing."

Kate mumbles in agreement, even as she feels her eyes getting heavier as a result of the additional stress on her body and mind over the last few hours. "Thank you, Castle," she whispers, only when she hears the door open to the bedroom.

"Whatever you need, Kate. Always," he responds, before shutting the door behind him and letting her sleep away the remainder of the afternoon.