I cannot emphasise this enough **SPOILER WARNING**!

Seriously - all of the dialogue at the beginning (before the phone call - after the phone call is ALL me though :)) is taken directly from the recent sneak peek and from the promos (both the Canadian and US ones). If you don't want to be spoiled for the Finale - DO NOT READ!

Disclaimer: They're not mine. In fact, this time around, many of their words aren't even mine. This story is a bit of a pastiche of snippets and bits and pieces that I've stitched together into what I think is a plausible play out for the finale. Do I want it to be this dark? Nope. But I can only play with the toys that Marlowe gives me. And he's not being very nice right now.

Rabbit Hole

He stands, facing her down in her own apartment, gun in her hand, fury in her eyes, and no small amount of fear. And he's afraid now that he's crossed that line – the line that can't be uncrossed.

His cards are on the table now and they can't be taken back. Then again, maybe they just won't talk about that too.

As she's walking away from him again he feels his own anger and frustration begin to boil over.

"You know what? This isn't about your mother's case anymore. This about you needing a place to hide – because you've been chasing this thing so long you're afraid to find out who you are without it."

"You don't know me Castle," her voice is raised now, her words thick with anger. "You think you do, but you don't," she nearly spits the words out at him.

"I know you crawled inside your mother's murder and didn't come out. I know you hide there. Same way you hide in these nowhere relationships with men you don't love," he knows he's crossed the line now, but his own anger eggs him on. "You could be happy, Kate. You deserve to be happy."

He realises after the words are out that he's not ready for her answer.

"Castle, we are over."

And that was it. There was the slap in the face. The shove out the door. He wished who could have said that he'd seen it coming. He really should have. This was her mother's murder. And he'd pushed her back into it.

"Why don't you want to investigate it?"

"Same reason a recovering alcoholic doesn't drink. You don't think I haven't been down there? You don't think I haven't memorised every line in that file? My first three years on the force, every off-duty moment was spent looking for something someone missed. It took me a year of therapy to realise that if I didn't let it go it was gonna destroy me. And so I let it go."

Her words haunted him now. She'd warned him. God, but she had warned him. But as usual, he'd only heard what he'd wanted to hear. He heard the fear and the apprehension in her voice – the self-doubt, the self-recriminations. And idiotically, he thought that somehow, he could fix it.

"It's because you're afraid, isn't it? You're afraid that if you look into your mother's death that you will go back down that rabbit hole and lose yourself again. But it's different this time – we have good leads, we have strong leads. And you won't have to do it alone – we'll do it together."

What if I don't want to know? Did you ever think of that? What if I'm not ready? What if the idea of catching my mom's murderer and then having to sit there and watch as he cuts some deal that puts him back out on the street in ten years make me nauseous? You dredged up my past for you Castle, not for me, and you're too selfish to even see it."

She's tried to tell him so many times. So many times she'd tried to stay away from the case out of her own sense of self-preservation.

And there he'd been, since very nearly the moment he'd met her, pushing her, forcing her to stare back down that dark hole, doggedly believing that the truth would set her free.

And it might still – if she's still alive for it. If she doesn't self-destruct. If she doesn't end up so far down that rabbit hole that nobody, not him, not the captain, not her own father, would ever be able to reach her.

He'd always believed in happy endings. Always believed that, with enough persistence, enough money, or enough resources, anything that he wanted badly enough would eventually be his. Anything that he desperately needed would work out in his favour.

Right now – seeing the finality in her eyes, even as the fear lurked there and something else he couldn't define, he found himself questioning that belief.

The person standing in front of him, staring him down, daring him to make his next move – that person wasn't the Kate Beckett that he knew. He almost wants to laugh at the irony or her words only moments ago. Maybe he really didn't know her after all.

As he's about to stalk out of her apartment, his shoulders slumped in defeat – he's stopped by the simultaneous ringing of both their phones. It's enough to break their staring match as they turn their backs on each other to answer their respective calls.

"Beckett."

"Castle."

The next words either of them hear will knock the wind out of them. It will cut their knees out from under their bodies. And it will shatter their lives in ways they won't fully comprehend for months.

As they hang up, their movements nearly synchronised despite the fight from only moments ago, they find themselves unable to speak, moving as if through water before collapsing under the weight of the burden they just got heaped up on top of them – him on the coffee table, her on the couch.

It could've been minutes or hours before either of them moves, let alone speaks, trying to absorb the news. When their eyes finally do meet, he finds himself staring into the starkest grief stricken eyes he's ever seen in his life – and it cuts through him more harshly than her words form before.

And then he sees it. She's crumbling now. The weight of her world collapsing around her as the tears start to gather just ahead of the coming storm. And he's moving without even realising it. He's catching her before she hits the ground. He's holding her together as she shatters into a million pieces.

"Castle?" her voice sounds so hoarse and broken as it sounds against his chest.

He pulls back from her, not enough to let her go, but enough to let them speak.

"I'm so sorry, Kate," his own voice hitches, his own eyes are glassy.

And she's buried in his arms again without another word. Her grief pouring into the man that, only minutes ago, she had been prepared to throw out of her life again for telling her things that she didn't want to hear. And even in her grief she is amazed by him.

They don't talk about it, but she knows. She always had. He proved it again, and again, and again. And after everything they been through, everything she's said to him, he's still here, holding her together.

Again neither notices the passage of time as they sit wrapped up in their collective grief. Grief for a man who had been like a father to both of them, in many respects. He'd been the father she'd lost, if someone temporarily, to alcoholism. He'd been the father he'd never known or had. And now, that man was gone and it was this case that killed him.

And through the guilt, her resolve to finish this case solidifies even further. She knows he can feel the change in her thoughts – she feels his arms stiffen around her.

"I'm coming with you."

"Castle, no—"

"I'm coming with you, and that's final."

As their eyes meet, there is a temporary truce. This isn't over, but for now, there are larger concerns.

"Don't you dare make me call Alexis."

Her meaning is clear: "Don't you dare make me call Alexis to tell her that I've gotten you killed"

"Don't you dare make me call your father."

He leans in then to claim her lips in a hard kiss. It's not a soft, but harsh and fierce. It's a promise and, though he doesn't want to say it aloud, it's probably a goodbye, for one, if not both of them. He feels her responding and knows that, once again, they're back on the same page.

And then her gun is drawn and she's handing him her spare as they make their way out of the building to her car. Shoulders squared. Eyes forward.

There was a conspiracy to blow open.

Please read and review - I'd love to hear what other people thought of the previews and sneak peeks too!