A/N: in light of the season finale, i'd love to make this officially AU, but who knows how she'll answer. i do assume, either way, that this is not how season six will actually go... so AU in that sense.

"So we beat on, boats against the current, borne back ceaselessly into the past." – F. Scott Fitzgerald

"You never wanted this to last, did you, Kate?"

She's caught completely off-guard by the sudden question, the swift change in tone, by the deep pain she can almost feel radiating off of him.

She knows immediately that she prefers the anger, the fighting, to this.

"What? How can you even say that? How can you even think that?" She hears the indignation in her voice and is proud of it, proud of the way she has the anger still buoying her.

As though it makes her the better person here, as though it somehow makes him so very wrong.

But he keeps going, answering what she hoped to be a rhetorical question. What ought to have been a rhetorical question.

"You've been looking for reasons to leave for months now, Kate. Every time something has come up, you've questioned this. Us. Me."

"No. No. What? No. Castle. No."

He holds a hand up to stop her, and she shuts her mouth immediately.

He's never tried to silence her, and where she thinks she should feel anger at this sudden display of arrogance, she only feels a deep, dark dread.

"You've let murderers make you question us. Literally. Actually listened to what a murderer said about relationships, about us, and then stood there and wondered those same things. You asked Meredith – of all human beings on this earth to have that discussion with – why our marriage went wrong. And, more recently of course, you let Eric Vaughn practically woo you. You let him kiss you. You let him get inside your head with his charming smile and pretty words after knowing him for all of four minutes. Which, I might add, is the exact opposite of how you treated me for four years."

He stops, seemingly out of breath, out of steam, and deflates. But then he soldiers on, the words pouring from his lips like darts against her skin, leaving her stunned by the dark conviction behind them.

"You've been collecting evidence against us all year, Kate. I should've seen this coming. In reality, I probably should've walked away after you heard me tell you I love you and then said some things are better not remembered. After you stopped speaking to me for three months, lied to my face for a year."

She takes a step toward him before she even realizes she's doing it; his step back is what brings her crashing back down to reality.

A reality where he doesn't want her near him.

"No, Castle. Rick. No." Her voice is hoarse, her eyes burning, as his words cut straight through her heart.

"I shouldn't have forced you into this."

She doesn't even know what this refers to – their partnership in the first place or this relationship – but it hardly matters. She can't even breathe, can't get the words out to make him see that he's wrong, he's so wrong and how can he not see? How can he think that?

But she knows the answer to those questions. He's laid it out before her, the timeline of her betrayal.

She wants to stop him, wants to point out all the good they've shared, how incredible it's been, how much light he's brought to her life.

The Hamptons. Christmas. His birthday.

And all the moments in between. The best year of her life.

But none of those words come out. She's stunned into silence.

"I should've walked away a long time ago. I'm sorry that I didn't, Kate. I'm sorry that I've clearly backed you into a corner, and I'm sorry I didn't hear all of those questions for what they were."

The tears are coming steadily down her face and she does nothing – can do nothing – to stop the flow.

"Rick." The word is mostly air, her throat thick with it all, a knot she can't breathe around.

He looks at the floor, shakes his head.

"It's okay, Kate. You don't have to say anything. Take the job. You'll be amazing. You'll do great things."

He pauses, looks up at her, and she sees how much this is costing him, the shine in his eyes, the tremors running through his body.

"I won't hold you back any longer. You're going to do big things, Kate Beckett."

He takes another shaky breath as the tears start to escape from his eyes.

"I love you. I don't want you to ever doubt that. I love you and even if this was never meant to last, even if you could never feel as much for me as I've felt for you, I won't apologize for loving you. Only for how selfish I let it make me, how much I took from you when all you ever wanted was an opportunity like this."

He smiles softly at her through his tears, his eyes somehow both anguished and adoring.

It's the most hauntingly beautiful thing she has ever seen.

"And this is your chance to catch him, Kate, to bring him down once and for all. I know you know that. I know you still want that. And you can still have it."

He's wrong, it's all wrong, and it aches everywhere, but he's also right and that stings even more.

She's thought about what this could mean for her mother's case, thought about how much more power, how many more resources, she'd have at her disposal. How she could finally take Bracken down.

And here it is again, the break in her life, the moment where everything falls back into place, her mother's murder back on center stage, her heart cowering somewhere on stage left.

It clicks as though it is the right thing, as though this year – and the years leading up to it – have blurred her world, not made it clearer.

As though it was a break, a blip that she will look back on with some fondness.

She's seen this moment over and over again, knew it was really only a matter of time before it happened.

She never imagined it could hurt like this.

She wants to respond, wants to refute his claims, wants to kick and scream and beg.

But he's right and she's frozen, rooted to the spot, the words trapped in her chest, the apologies and the pleas and the love all stuck behind the hard lump in her throat, the grief filling it all as though it never left.

And suddenly the room is spinning and her vision is tunneling and her chest is tight and oh no, not this, anything, anything but this.

And then she is moving, her feet somehow taking steps, her body moving out of his office. Out of his loft.

It takes a full minute for her brain to catch up and realize he is guiding her out, and by then they're all the way at the door.

He places her bag in her hand. She marvels at the fact that it doesn't simply fall off under the weight of it all.

When she still doesn't move, he opens the door for her. He places a soft kiss on her cheek, and then his hand is on her back, softly guiding her out.

The door closes.

She finds herself exactly where she started.

Love and happiness on one side, her fight for justice – whatever that even means at this point – keeping her firmly on the other.

Eight years later she does take him down, just as his presidential campaign starts to pick up, just before he manages to squeak by and become the most powerful man in the world.

It's a victory, not just for her, but for all the other lives he's taken, all the parents and siblings and children whose lives he ruined.

For society at large, really.

She doesn't feel victorious.

It's two years after her father's death and all she feels is so very alone.

It's all over the news for weeks afterwards, of course, so she isn't terribly surprised when she receives a letter from him. Even though it's unsigned, even though it's been years and years – almost a decade, her mind ruefully provides – the penmanship is still unmistakable to her. The message even more so.

Kate,
I hope it brought you the peace you so deserved.

It didn't.

And she feels hollow with the realization that it could never have been enough.