Summary: She doesn't love him. In his heartbroken state, it's the only explanation that makes sense. Except that trying to move on from the future he was sure they would have is easier said than done.

Author's Note: Because I'm in an angsty mood. Because I feel Castle's pain. Because I'm going to be upset if he sleeps with Ms. Blondie Way-Too-Tan. Because I love the angst on the show but I wanted to give them their happy ending before the season finale. And because I want Becks to be jealous and fight for him. Spoilers for 4x19 and 4x20.

Disclaimer: No. Just, no.

Irreplaceable

"Who is she?" Kate spat harshly, shoving him against the break room counter hard enough to leave a bruise on his lower back.

"Who...what?"

"The blonde. Your lunch date." The contempt in her voice was obvious.

"What's it to you?"

"Castle."

"No really...why do you care?"

Kate fixed him with a defiant glare, but when his expression did not change, she realized that he was serious. He was really going to make her say it, right here, right now, in the break room at the precinct when they were both obviously furious with each other and in no frame of mind to have this type of conversation.

She took a deep breath, struggled to find the right words. This was certainly not a moment to fumble over her thoughts and end up making things worse. Unfortunately, that seemed to be all she could manage lately.

"Because you said...I thought we were...I thought I was who you wanted, Castle."

When he spoke, his voice was devoid of emotion. "Not anymore."

His words hit her with a force she was unaware they could have, causing her to stagger backwards and very nearly fall over.

A few months ago, he loved her. Now, he did not. And really, there was no way that could not be debilitatingly painful.

"Really, that's it? Just like that, you can turn your back on everything we had?"

His face was stoic, eyes hard. "We never had anything, Beckett. I was kidding myself."

With that he turned on his heel, left the break room, the precinct, without looking back.

"Castle..."

Richard Castle was failing. Miserably. He wanted so badly to believe that he was getting over her, that he could be happy without being head-over-heels in love with her. But so far, things were not going as planned. The damage on his heart was irreparable, their love irreplaceable. He was in too far, so far he would never be able to climb out, not completely. Nevertheless, he was going to try, because what was the point of loving someone who would never return his feelings?

He had a date last night, his lunch date today, too, with a shallow, overly-tan blonde he met at a coffee shop. They went out for dinner, had some wine, talked. He even managed to laugh and smile and almost enjoy himself. She was funny enough. She knew enough to carry on a conversation that had nothing to do with reading or current events or anything that Castle and Beckett usually talked about. She was nice-looking, but only with the help of far too much make-up and other body enhancements. Just the kind of woman he would have been all over two or three years ago.

But not now. Not after Kate. She did not have the wit or intelligence or effortless beauty of his partner. She was a filler, was just there to help him forget. It worked after Kyra and Meredith and Gina. But it had not worked this time, because with everything she said, everything she did, he found himself comparing her to Kate. And she never came close to measuring up.

If he was honest with himself, no one ever would. Kate was everything he had ever wanted and more. She had turned his life around, had made him a better man, had made him believe in love and forever when he had been completely disillusioned by the concept prior to meeting her.

Then, with one lie, one slip of the tongue, she had taken that all away from him; though given her feelings, or lack thereof, he had obviously never had it to begin with. It was just a fantasy he had dreamed up and blindly clung to for far too long.

Regardless, he still loved her. Part of him would probably always love her, because how could he ever not love Kate Beckett? The best he could hope for was to find someone who could make him forget, who could make their own mark on his heart.

Whatever it was, some combination of those reasons was why the date last night had gone no further than dinner. At the beginning of the evening, he had fully intended it to. He had planned on waking up in a strange bed tomorrow after a wild evening that would at least temporarily relieve his misery. But when the time came, he could not do it. Could do nothing more than kiss his date goodnight at her door, because her lips were not soft enough and the little sound she made was not seductive enough and her hands in his hair just felt...wrong.

It was all wrong.

He had gone out on this date to forget about Kate, to prove to himself that he could keep working with her and writing about Nikki Heat and not be in love with her. Instead, the evening had only reinforced his feelings for her, reminded him how much he loved her, how badly he wanted them to have a future together. It made him want to keep loving her, keeping holding onto his dreams and hopes for the future, no matter how futile a venture that would be.

That made him insane, right? Doing the same thing and expecting different results? Well, no one ever said his love for her was rational.

It was not the first time he had done something completely crazy for her. But in his eyes, everything he had done, crazy or not, had been completely justified. Because it was for her, and he loved her like he had never loved anyone, and he would do anything for her.

Maybe his mother was right; maybe he could not keep working with her and still expect the feelings to go away. Maybe the only thing to do was to walk away completely, do the one thing he had sworn he never would. He had said always, he had meant it, and he had wanted it, more than anything. Now, it was slipping away, with every moment he spent not in her presence.

Maybe this was one promise that would have to be broken.

After last night's failed attempt, tonight Castle had tried something different; he had gone out alone, to his bar, to have a few drinks and try to make himself forget.

Unsurprisingly, it was only marginally successful, and anything he might have accomplished disappeared completely when he stepped out of the elevator onto his floor.

There, seated on the floor outside his door was Kate. Beckett, he reminded himself. She was Beckett now, all the time.

She looked up at the sound of his footsteps, and he could see from the red rims of her eyes that she had been crying. Ordinarily, he would be worried. Right now, his only thought was that she deserved it.

"What are you doing?" he asked, probably harsher than he intended, but he had had a bit too much to drink and was not at all happy to see her.

She stood but did not approach him. "Waiting for you."

The layers to that statement were not lost on either of them.

"Why?"

"I think there are some things we need to talk about."

He shrugged, stepped around her and unlocked his door. "Not really."

"Castle."

"I'm serious. I don't have anything to say, Beckett." He stepped inside, made no move to allow her in after him.

"Look, I..."

"Please, just go."

He made to shut the door in her face but Kate was faster, wedging her body in the gap, halting his progress. She knew that this was it; this was her last chance. If she lost him now, she would never get him back. And that called for desperate measures.

"Castle, you don't get to do this. You don't get to freeze me out without at least explaining it to me."

"Oh really?" he snorted. "But you can?"

She pushed the door open, stepped inside after him. "What?"

"Last summer. Three months." His voice was cold, his eyes cutting through her like ice. He was standing in the foyer, glaring daggers at her, everything about his posture suggesting that he was just barely restraining the urge to physically hurt her. "And yet you can't give me three days of space."

"This doesn't feel like space. This feels like you running."

"Well now you know how I felt."

"That was different," she protested instantly.

"You're right, it was," he snapped sarcastically. "It was about you, which somehow makes it acceptable."

"It wasn't...I was wrong, Castle," she admitted quietly, though somehow she doubted that her less-than-stellar behavior all those months ago was what was troubling him at the moment.

"Well maybe you should have thought about that before you lied to me for almost a year."

Lied? He knew about that? Oh. Well, that certainly explained his sudden change of behavior, his anger.

"I...you...how?" she stammered in shock.

"It doesn't matter how. It just matters that it happened."

"I..." Shit. She had really made a mess of things. And she certainly had not planned on him finding out like this. But now that it had happened, what choice did she have other than to just admit it and apologize and hope that he would understand? "Okay, yeah. I lied to you. I remember the shooting. I never forgot."

She saw his shoulders slump even more with her words, could see the pain washing over him. God, she was a horrible person.

"That's what I thought."

Castle stalked to the living room, sunk down on his couch with his head in his hands. She knew. Every day for the past ten months, she knew that he loved her, and she used that to her advantage. She used it to keep him coming back. To drag him along. To break his heart, in the worst way possible. If she had just told him back in May, he could be over her by now. Hypothetically. Instead, he was sitting on his sofa trying not to cry as she bumbled her way through and explanation that he really did not want to hear.

"Look, I screwed up, okay," she said softly, crouching down next to him, seeking out his eyes though he refused to lift his head. "I know that. I'm sorry, Castle. I lied because I didn't want to hurt you, but it turns out that was the only thing I accomplished. And I'm so sorry."

"That doesn't make it any better."

"You have to give me a chance, Castle."

He lifted his head, stared her down. "Maybe it's too late for that."

He stood then, headed for his office and the bottle of scotch he had stashed away in his desk drawer. He had given her countless chances, so many hours of his time. He had given her his heart. She had taken all of it for granted. And yet, she still had the nerve to ask more of him. Well, he was done giving. He was done with this conversation. And he just wanted to drown his sorrows alone in the dark of his office.

"Castle, wait..."

He stopped then, turned around, his eyes even harder than before. "I did. For months. For no reason. You really expect me to do the same thing again?"

"It wasn't...there was a reason, Castle," Kate blurted, not bothering to censor her words. Now was so not the time for that. "I know why you waited. And I can't even begin to tell you how much it means to me that you did. That you gave me the time to work through some things, to try to heal and be better, for you."

"For me?" he asked incredulously, the tense lines of his face relaxing slightly.

She took a step towards him and when he did not back away, she took another and then another. She was trembling, her entire body, either from the anger or the adrenaline or the nervousness that was threatening to overwhelm her at finally verbalizing her feelings. Probably the latter.

Kate reached out, placed her left hand over his heart. "For you. I wanted to be more. I didn't want to be broken and enveloped by my mom's case. I wanted to be strong and free of all of that. I wanted to be able to let you in. But most of all, I didn't want to be the person who hides herself away in relationships, who always ends up ruining them by being distant and unwilling to open up. I didn't want to ruin what we have, Castle."

"You..." he forced his brain to catch up, to process her words. "You lied because you thought I'd leave if you told the truth?"

"No, Castle." She raised her free hand, cupped his slightly-stubbled jaw. "I lied because I was afraid you'd stay, and I wasn't ready for that. You're...I love you so much that it scares me. We have so much to lose, and we could hurt each other so badly. And I would never forgive myself if I was the one who destroyed us because I tried to dive in when I wasn't strong enough to keep my head above water."

"You were going to tell me?"

"Yes, but..."

"You love me?"

Kate could not help it; a broad smile split her face, lifting the suffocating tension that had been hovering over them since the moment he laid eyes on her in his hallway.

She dropped her right hand, curled it around his neck, tugging him closer. "So much, Castle."

He could feel her breath on his cheek, her nose almost brushing his. Her eyes were brimming with hope and love and that was enough to make him forget everything and close the distance between them. His arms wrapped around her tightly, anchoring her to him as their lips met, gentle and testing at first, then gradually more confident.

Her lips were soft, her hands caressed his chest, his shoulders, his neck, and it was exactly like he remembered, only better because this time was real and she loved him.

Both of her arms eventually came to rest around his neck, clinging to him as though her life depended on it. His rested on her hips, inching beneath her shirt and tracing patterns on her bare skin. And, God, it was sending heat through her veins, the sensations he was evoking without even trying.

Kate smiled into the kiss as his fingers found the waistband of her pants, dipped beneath it teasingly. She felt him smile back and broke their kiss, burying her face in his neck. She felt him hug her tighter, was almost positive that he had just smelled her hair. Typical Castle.

She relaxed into him completely, allowed his love to overwhelm her as he continued to hold her tenderly. Maybe she had not broken them completely. Maybe this was still fixable. It was not ideal, but they had survived much worse.

Tomorrow, there would be some difficult conversations waiting for them. There were apologies to be spoken, explanations to be offered, and promises to be made. There was broken trust to be healed and betrayal to overcome.

But for tonight, it was just them and their love and his soft caresses and her whispered words as they lay tangled up in his sheets, wide awake until the morning light began to peek through the slats of his blinds.

It was Kate opening up and trusting Castle with her heart, her soul, her love, her everything.

It was the way he woke a few hours later with her curled into his side, hand resting over his heart.

It was unconventional.

But it was love. And it was theirs.

And that was more than enough.

THE END

Thoughts?