I stayed true to the dialogue in the show, words may not be exact but the content gives the same feel and emotion. (My excuse for being too lazy to want to look up all the dialogue)

For Castle's view, I wanted to get across how hurt he is by Beckett's actions. That his actions over the last four years seemed to mean nothing to Beckett in that instant. (Hopefully I was able to get that across in this chapter.)

Disclaimer: I don't own Castle.

Castle's perspective

It wasn't how he wanted their conversation to go. He didn't want to leave when he had been the only person to ever really stay. Walking out on her hurt more with every step and if his legs had listened to his heart and not his head, they would have turned around and went back to her side. He did what he knew he had to. Everyone expected him to stop her from getting swallowed whole by her mother's case. Montgomery, her father, the guys, even Smith. Every single one of them had told him in slightly different ways he had to keep her afloat. Not let her drown. He told himself he had to be the one to do it too. Everyone kept telling him if he couldn't get her to stop no one could. And he wanted to be the guy who could get her to stop. The one she could cling to when everything else around her crumbled. He wanted to be her solid ground. But he was torn. He was torn because if he told her to stop and she shut him out, then he couldn't be there for her and she may keep him out of her life forever.

And then he saw Kate slipping. Falling deeper into the case and he had to do something. Because the last time she couldn't stop she was shot. He had to watch. The bullet may have hit her but he was feeling some of the pain. With blood on his hands and a hole in his heart, he watched her die. He held her hand in the ambulance. Even as she struggled to fight for her life; he was there. He said always and he meant it every time. And remembering their word and how he left her alone in her apartment, it made him realize they broke the promise.

The promise of always. Shattered when she refused to listen to him and shattered when he gave up trying. Their always broke when he walked away and didn't look back. But as much as it killed him to say goodbye to Beckett, it had hurt him more to stay. He never knew if today would be her last or if tomorrow he would receive the call. A call saying Beckett was murdered. One he would never voluntarily answer.

He still had to deal with the uncertainty of it all. Now he would never know if she was okay, but he had to protect his heart. He left it unarmored since the day she was shot. Maybe even before. And every time he had tried to move forward with her, she had held back. He had been with her for four years. And for those four years he never expected more than her company and friendship. She had all of him and he was alright with only getting part of her.

He knew that having part of her had been better than none at all. But after four years, he needed more. He told her did when he came to her apartment and told her to stop. When he reiterated that she knew he loved her. It wasn't the best time to do so, to have an actual meaningful conversation, but it never was with the two of them. Before he was mad she hadn't let him know she heard him. That she lied. He was willing to forgive. He couldn't forget, but he could forgive. If she would have just told him she cared for him, he would forgive the lies. He would forgive and stay if she stopped looking into the case and chose life over death.

The part of their conversation that hurt him the most wouldn't leave him alone. The part that somehow had the ability to make him furious and feel physically sick at the same time.

"Listen to you? Why should I listen to you? How am I even supposed to trust anything that you say?"

"How are you su—?

Because of everything we've been through together! Four years I've been right here. Four years just waiting for you to just open your eyes, and see that I'm right here…and that I'm more than a partner. Every morning, I—I bring you a cup of coffee just so I could see a smile on your face, because I think you are the most...remarkable…maddening…challenging…frustrating person I have ever met. And I love you, Kate, and if…that means anything to you, if you care about me at all, just don't do this."

"If I are about you? Castle, you cut a deal for my life like I was some kind of a child. My life. Mine. You don't get to decide."

"You keep going like this, they're going to decide. They're gonna come for you, Kate."

"Let them come. They sent Coonan, and he is dead. They sent Lockwood, and he is dead. And I am still here, Castle! And I am ready!"

"Ready for what? To die for your cause? This isn't a murder investigation anymore, Kate. They've turned it into a war."

"If they want a war, then I will bring them a war, straight to their doorsteps."

He knew he wouldn't get her to stop. And after so much rejection he had to be done. Finally protecting himself and his heart before her own. She had a wall around her heart and it seemed to work for her. So he decided it was time for him to do the same. Distance himself and his heart, retreat, out of harm's way and into the safety of his chest.

Even before the words left his lips and his eyes met hers for what he imagined to be the last time, his body slumped in defeat.

"Well, I guess there's just nothing I can say, is there?"

Whatever battle it was here in Beckett's apartment that he was trying to win, he knew he had lost. He couldn't get her to close her investigation into her mother's case and he couldn't get her to admit that she cared about him.

His voice was low and full of dread, each word more difficult to scrape out than the last.

"Okay, um… Yeah, you're right, Kate, it's your life. You can throw it away if you want, but I'm not gonna stick around and watch you."

With the last bit of strength and dignity that he had, he said his goodbye.

"So this is, uh…over. I'm done."

He said all he had to say and there was nothing left. He bared his soul to her and even told her about the deal Smith made. He still remembers Kate's words blazing as they reached his ears.

He wanted to tell her that yes, he made a deal for her life, yes he was selfish to do so, and yes he would do it over again if given the chance. He would have told her he regretted keeping everything between him and Smith from her, but he would have countered that with, I was trying to keep you safe.

He wanted to say that in order for Smith to keep protecting her it was better that she didn't know about him. How he knew if she knew about Smith she would throw herself further into the case. That his action may have been selfish but he didn't ask to be put into this position. Either way he lost. If he would have told Beckett she may have already been killed. That he hated lying to her because they were partners.

But she never gave him a chance.

She basically waved him off and expected him to leave. She didn't offer him anything more than the silent declaration that she was ready to die for her mother's case. And part of him could tell that Beckett wanted him to go.

Castle never left easily before. Even when she wanted him to go he kept coming back. A coffee in his hand and an apology from his heart when he went too far. This time was different. But even now he would have stayed if it weren't for one thing. This time, he was broken.

She was the only person since Kyra that he gave the ability to break him. If she hadn't rejected him or if she had understood the position he was placed into, he may have stayed. If she would listened to everything, instead of picking and choosing words, stringing them together to hear what she needed to justify letting him leave, he may have stayed.

He had become her partner and with that came a responsibility he took seriously. He wasn't a cop so he couldn't protect her with a gun. He was a writer and he could protect better with words. Talking with Smith and making sure she wasn't being hunted down by the guys who killed her mother. Giving her words of encouragement that things would be okay. That was the protection he could give. And she was blind to it.

He would have stayed for a simple, "I care about you Castle," or an, "I cared about you until this Castle," but she hadn't even given him that. He just wanted to know that she had cared. He wanted to know that if this hadn't gone the way it did that they could have had their always. That the one word that kept him coming back hadn't been an empty declaration. Every time he had said it he meant it. He needed to know it had meant something to her too.

But all he received from Beckett was silence.

He replayed his leaving in his head so many times, sometimes it replayed how it actually happened and other times she stopped him from leaving. But he was always hit with the universal truth when the day dream came to a close.

He was alone and he had to move on.

Thanks for reading, would love to know what you thought.

To Be Continued.