Title: Never Sit in Another Man's Chair

Summary: Castle's feigned indifference can only go so far when the gang crimes detective he's following shows an interest in Beckett. Oneshot. Post 47 Seconds and The Limey, Spoilers for Headhunters.

Spoilers: Post 47 Seconds and The Limey, spoilers for Headhunters (written before seeing the episode but after the first sneak peek)

A/N: I promised myself I wouldn't write another one of these, but after watching the first sneak peek for Headhunters, this one sort of popped into my head. If they don't resolve this by Monday, I may be stuck writing angsty post-47 Second stories for the next two weeks.

"Are you sleeping with her?"

Slaughter's question came out of no where and hit Castle in the gut as surely as their suspect's fist had hit him earlier in the day.

"Who?" he choked out, although he already knew which 'her' he meant.

"That gal who was riding you about not being a cop just now. What's her name?"

"Beckett."

"Yeah, that one. She's pretty hot."

Castle nodded. "Yeah, she is. But no, I'm not sleeping with her."

"Trying to sleep with her?" the gang crimes detective pursued.

He wanted the conversation to be over. His whole reason for shadowing this man was to get away from Kate Beckett. He left it at, "Not anymore."

Slaughter grunted in acknowledgment, then asked, "Mind if I give it a shot? She seems like she'd be a wildcat in bed."

If he wasn't already so upset, Castle would have found the very idea of him having a chance with Beckett as comical. Instead, the question just smacked of bad taste and the taste of ashes from something he'd hung so much hope on. "Knock yourself out," he replied bitterly.

He spent the rest of the day with Slaughter, who occasionally threw him a question relating to Beckett.

"So she's not seeing anybody?"

"Is she really as slutty as that girl in your books, Nikki Heat?"

"You finally just give up on her, or what?"

Castle gave one word responses as he struggled to keep up the mask of indifference he had spent so much energy creating. Underneath that mask, he was seething at every word coming out of Slaughter's mouth. He didn't want Kate dating another man; he wanted her for himself. But quite clearly, she had no interest in him. She had known about how he felt for nearly a year, and she had not only said nothing about his declaration, she had lied about even hearing it. Repeatedly.

At the end of the day, Slaughter dropped him off at the precinct. Castle wanted to just go home, to drown himself in a bottle of something expensive and smooth, but he'd promised to drop off some Knicks tickets he'd procured for Esposito and Ryan. It was sort of a goodwill gesture since he knew the guys were angry at him for leaving their team to follow Slaughter. He wanted to explain, to express to them how impossible it was to be around Beckett, but he didn't want his motives getting back to her.

Of course, Slaughter followed him up in the elevator, probably looking for a chance to score with Beckett. Realizing he would have a front row seat for that conversation, Castle regretted not just going straight home. But he was committed now.

All three of his former team members were still there, although rather than sitting at their own desks, the guys were standing around Beckett's area. Neither had attempted to take the seat beside her desk - his seat - and the picture of them without him seemed wrong, incomplete.

"Hey guys," he greeted them with false cheer. "Look what I got!" He held out the basketball tickets

Esposito nailed him with an expression of rage he must have perfected in the military. Even Ryan seemed angry. Neither man responded to him, but each gave a knowing nod to Beckett before turning and heading back to their desks. Castle forced himself not to look at Beckett, who had turned back to focus on her paperwork without acknowledging him. Instead, he followed the guys.

Behind him, he noticed Slaughter also stop at Beckett's desk. "Detective," the man said in a gruff-but-friendly tone.

She didn't look at him either, responding with a dull, "Slaughter."

Then the man did the unthinkable. He sat down in Castle's chair.

He realized he was staring at them when Ryan tapped him on the shoulder. Turning back, he looked at the Irish detective in surprise. "What are you doing here?" Ryan demanded. "And why'd you bring him?"

The 'him' in question had launched into small talk, but Beckett was doing her best to ignore him and focus on her paperwork. The picture of them together like that, with Slaughter in Castle's place, was so horribly wrong...

"I didn't bring him. He tagged along. Probably trying to get Beckett's number."

This time Esposito shot him a look of warning. "Well you better get him out of here now or we're going to be investigating one of our own for murder."

Beckett clearly was not pleased by Slaughter's presence. Whatever the man was saying to her in low, intimate tones was rapidly turning her irritation to anger, and from there to flat-out fury. Suddenly, he said something which must have struck a particularly sensitive nerve, because she swung her eyes towards Castle and Slaughter did the same. Her expression held not only anger but also hurt and humiliation.

What had Slaughter said to her?

"Looks like you're the one she's going to kill," Ryan said as Beckett pushed herself out of her chair and stalked towards them. Even the clicks of her heels on the floor sounded furious. Ryan and Esposito took a few steps back, abandoning Castle to her ire.

"What the hell, Castle?" she demanded. Over her shoulder, he saw Slaughter grinning as he checked out Beckett's ass. He was really starting to hate that guy.

"What?" he responded, genuinely not sure what he was in trouble for.

"You told Slaughter you thought he and I would be 'good together'?"

He snuck another glance at the gang detective, who shrugged in feigned innocence. Scratch the 'starting to.'

Castle answered, "I didn't say that."

"Then what did you say?" She moved her hands up, and for a second he thought she might slap him. But she merely folded her arms across her chest.

"He just asked if you were available, and I said you were."

She stared at him in confusion and horror before taking a small breath and looking away. Before answering, she blinked rapidly, as though to clear tears that were forming. "Well maybe you should check your facts before you try setting me up with one of your buddies, Castle. Because I am NOT available."

Her statement hit him like the proverbial ton of bricks. Whatever weight he had been carrying multiplied tenfold at the idea of her involved with another man, one she obviously hadn't told him about. He forced himself to sound nonchalant as he remarked, "Well I didn't know you had a boyfriend."

"I don't have a boyfriend," she shot back immediately. "And you know it."

"You sure seemed pretty chummy with Mr. Scotland Yard," Castle pointed out.

Her eyes narrowed into a glare. "I'm surprised you noticed anything what with being up to your eyeballs in bottle blonde bimbettes."

Castle forced out a laugh. "Jealous, Beckett?" he asked. But she just shook her head at him. The anger was melting away, leaving in its wake only sadness and pain.

"You know what, Castle," she began, "I don't think this is fair. You may be over this-" she gestured between them "-this whatever it was between us that we almost had. You may have gotten sick of waiting and moved on to flight attendants and whoever else you're seeing. I understand that; I missed my chance. But it isn't fair for you to come in here and try to make yourself feel better by getting your new friend over there to ask me out in some insanely misguided attempt to force me to move on. I will get over you when I'm good and ready, not on your time schedule." He opened his mouth to speak, to argue with her, to clarify a few things he wasn't sure he heard correctly, but his mind wouldn't work. He couldn't process what she was saying fast enough. "So just go home, Castle. And take Slaughter with you."

A moment later, she was gone. Castle looked around, but he had been so distracted by what she'd said, he had no idea which direction she had left in. Three pairs of eyes stared at him - Esposito and Ryan looked at him expectantly while Slaughter's expression read simply as, 'What the hell just happened here?'

The gang detective was the first to speak. "I thought you said you two weren't knocking boots?" Castle ignored him.

Instead, he looked to his friends, both of whom seemed as surprised as him, although Esposito perhaps less so. "I think I may be the world's biggest idiot," he told them finally. "Did she really say..."

Esposito nodded. "Yeah she did, and you are the world's biggest idiot, bro."

"What did you think, that she didn't have feelings for you?" Ryan asked. Upon Castle's nod, he observed, "You must be completely blind if you didn't see it. Everyone saw it. We all just thought you were letting her get herself together after the shooting."

He was still so confused. "But she lied... She's known all this time how I felt, but she pretended like she didn't hear me."

"And what did she say when you confronted her about it?" Esposito asked. Castle's guilty look answered his question. "Yeah, that's what I thought. You two have such communication issues."

"Speaking of which," Ryan put in, "Why exactly aren't you going after her?"

Castle's eyes lit up, as though the fog around his brain had finally lifted. "Right! I gotta go." He turned once, then back, locked in indecision.

"That way, bro," Esposito pointed towards the stairs.

Castle took off in that direction leaving a confused Slaughter behind him. The abandoned detective looked over at Ryan and Esposito, who had resumed their previous glaring, this time at him. "What?" Slaughter asked.

"Not your chair, man."

When Castle failed to catch up to her in the lobby or on the street, he flagged down a cab and gave the driver her address. As the car pulled into traffic, he realized he should call her. Of course, after five rings, it went to voicemail. He left a message but without hope of her calling him back. Putting his phone away, he resolved not to call her again before getting to her apartment. But within thirty seconds, he had it in his hand again and once again, five rings later her familiar voice was advising him to leave a message.

The next call went straight to voicemail. She must have turned off her phone. Just in case, he typed out a simple text message: *I'm coming over.* Beckett still hadn't responded by the time he paid the cab outside her apartment.

She also didn't answer her door when he knocked. Just to make sure she wasn't screening her door as well as her calls, he beat on it frantically like a madman and screamed, "Kate!"

This got the attention of two neighbors - one elderly woman with her hair in curlers and one body-builder type guy with scary looking tattoos - and he promised to keep the noise level down. Besides, he felt certain that if she were home, Kate would have answered him by now.

Kate. It felt so good to think of her as 'Kate' again and not 'Beckett.'

Unsure what else to do, he lowered himself to the ground and leaned against the wall beside her door. He would wait for her. As long as it took this time.

Some time later - he had no idea how long - he heard her voice, surprise mixed with something else, as she said, "Castle?"

He blinked his eyes open and realized he must have dozed off waiting for her. And there she stood, looking the same as she had in the precinct, except now her eyes were puffy and swollen and moisture from unshed tears still lingered in her eyelashes.

Scrambling to his feet, Castle said her name, "Kate."

Wow. Saying it still felt good.

"What are you doing here?"

"I was... I was waiting. For you."

The double meaning of his words were not lost on her, but she snorted in disbelief as she put her key into the lock of her apartment door. "Go home, Castle."

"We should talk," he suggested as she pushed the door open.

While she didn't protest as he followed her inside, she responded, "I think the time to talk has passed, don't you?"

"I don't agree." He watched her carefully, as though she might break if he did this wrong. He wanted to get through this so desperately, this messy fight they were surely about to have. He wanted to move past the hurt and the pain and the resentment and get to the actual communication part Esposito had mentioned.

"Well, you will be happy to know that I figured it out," Kate said, her tone somewhere between flippant, annoyed, and utterly defeated. "After my little breakdown at the precinct, I went to see my therapist. Did I tell you I was seeing a therapist? Ever since that first case when I got back, and also for the PTSD. With his help, I figured it out - why you're so upset with me. You were in the observation room when I was interrogating Bobby Lopez, weren't you?"

He nodded.

"Yeah, that's what I figured out. So you know I lied to you about what I remember from the day I was shot." It wasn't a question. Neither was her next supposition. "And you think that means I don't feel the same way."

He couldn't stop himself. "Do you?" slipped from his lips before he could stop it.

She gave a sort of fake half-laugh and looked away, focusing her gaze on a nearby bookshelf. "Does it matter, Castle? I mean, at this point, does it matter how I feel? You've made it pretty clear you've moved on. You've stopped waiting. Instead, you've got Vegas, flight attendants, and Slaughter."

Finally, it was his turn. "When I thought you didn't feel the same way, yeah, I tried to move on. Pretty unsuccessfully, I'd say. Kate, I love you. No matter how much I try to ignore it or deny it, it's still there. My mother was right - it isn't just a switch I can flip."

She signed, deeply.

"Yeah, well, I love you too." The acknowledgment didn't seem to bring with it any joy. She said it like it was a weight hung around her neck, something she was unable to escape or hide from. "I was going to tell you about remembering that day at the cemetery. I've been working with my therapist for months, trying to just... get there. But then you started to pull away, and I thought maybe I'd waited too long. Rick... I'm so sorry."

She didn't have to say for what – her contrition showed on her face. Sorry for lying. Sorry for hiding. Sorry for taking so long.

He stepped towards her, the use of his first name reviving all his hopes. "I'm sorry, too," he said, and he genuinely was. His actions had been so foolish, so hurtful. He had seen her reactions - he knew how he had been effecting her - and yet, he'd done it anyway. Perhaps out of spite or his own angry stubbornness. Either way, no excuse could justify his behavior.

"Where do we go from here?" Kate asked. She wore her vulnerability openly, no longer disguised by anger or sadness. It was suddenly so clear to him, her need shining through, despite the repeated rejections he had lobbed at her.

Wanting to give her comfort, to give them both comfort, he pulled her into his arms and held her as tightly as he dared. "We go forward. Together."

"Together," she agreed. Even if they still had a ways to go, at least they were finally headed in the right direction.

They pulled apart just enough to allow for a kiss. At first it was soft and chaste, just a peck on the lips. But recognizing the need for more, their lips met again, this time with greater passion as they finally let themselves succumb to their mutual desire and affection. So much better than the 'undercover kiss' they'd shared before, Castle decided. They were both breathing hard by the time they broke apart.

"By the way, I'm going to kill your friend," Kate said, and for the first time in a long time, she smiled.

Castle looked at her in confusion. "What friend?"

"Slaughter. He's a real jackass."

He laughed. "You can't kill him if I get to him first. Not only did he hit on you, he sat in my chair!"