A/N - I found this unfinished in my files. (There is a vast, vast wasteland of unfinished things in my files.) I think I must have started it in between season 3 and 4, so spoilers through the end of season 3. Major character death, several times over.

Than to Survive

(It could have been different.)

Castle's having the best time ever.

This case has everything; stolen fake purses, underground immigration, voodoo - real voodoo, awesome - and it's fantastic, hilarious fun, at least until the shooting starts.

For a second Castle's honestly shocked, because this isn't really supposed to be dangerous. But then he's actually holding Kate Beckett, in his actual arms, her body against his as he flips her behind the couch at the last second, bullets and exploding glass all around them.

And okay, maybe she only tolerates it because he's saving her life, and it only lasts a moment before the gunfire necessitates that they untangle their limbs and crawl behind the kitchen island, but still. Beckett. Pressed against him. And now he's involved in an actual gunfight, and this is bad, bad but it's also a little bit awesome.

Well, perhaps he isn't directly involved in the gunfight. He's more crouching and trying to shield himself from the astonishing amount of flying glass, but Beckett is shooting things and wow, he would have said she couldn't get any hotter than she already is, but he would have been wrong. And she's got this, she's so got this, this guy's toast, she's…

Almost out of bullets. Wait.

The guy fires off another round, Beckett barely ducking behind the counter before a shot whizzes thisclose to her head, and Castle's frenzy of excitement abruptly twists into something…not fear, but…

The gunman shouts that he'll walk away if they give him what he wants, and yeah, okay, like Castle's never written this before.

"We give him what he wants and you know how this ends?" he hisses at Beckett. "Badly. And by badly, I mean us dead."

"Just stay down," she says, even though he isn't up.

"You stay down!" This isn't fun anymore.

"I can't shoot him from down here!"

"Yeah, well, he can't shoot you either!"

She half rolls her eyes and barely lifts her head over the counter before dropping back down. "I can't see him."

"Shhh." There's a pause in the gunfire. "He's moving."

But then another round rings out. The guy is obviously desperate, there's no way he can see them to get a good angle. The shots fly wide like all the others.

Except for one. One ricochets off the stainless steel counter behind them just as Beckett turns her head, absolutely perfect timing. The bullet slams into her temple, and just like that everything is over.

Castle doesn't remember much about the rest of that day. He tries not to remember. Tries not to think about how the whole world can change in an instant from light to dark, how hope and possibility can just disappear. It's the worst day of his life.

He writes one Nikki Heat novel. It gets a lot of critical attention for its excessively dark tone and violent ending, but has only modest commercial success. He loses his touch and his taste for mystery writing, and retires at 40. The rest of his life he's haunted by the vague but constant feeling that something is missing.

Castle never forgets the date of Kate Beckett's death. His grief at the loss of her always seems out of proportion and somehow embarrassing, like something he hasn't really earned.

(So many times…)

The flames are sharp and sudden against the night sky, the explosion knocking him to the pavement.

Or maybe it's the sick shock that brings him to his knees.

But not for long. One minute Castle is on the street blinded by the fireball where her apartment should be, and the next he's busting in Beckett's door, screaming her name, his throat already raw with smoke and fear.

He finds her sprawled across the bathroom floor. Her eyes are closed, her body mostly covered by the towel still tangled in her fingers, and for one miraculous moment – the last miraculous moment of his life – Castle believes she's okay. Then he sees the blood and the bone where the back of her head should be, and he knows that nothing will ever, ever be okay again.

Everyone tells him that it isn't his fault, but he knows they're lying. Castle clings to it, that guilt. He tells himself that it's the reason for the raw and empty place in his heart. Alone in the dark of night he knows that isn't exactly true. The emptiness is where Kate used to be, a wound that will never scab, never heal, but in the day he can't bear to think that way, or his regret at what could have been will be more than he can stand.

He writes half-a-dozen Nikki Heat novels. The narrative thread weaving throughout all of them is Nikki's hunt for the elusive serial killer that murdered Jameson Rook. In the end Nikki catches his killer. She's triumphant and happy, riding into the sunset with her partner, a fellow homicide detective who always has her back, and never puts her in the cross-hairs of danger with his stupid, asinine schemes.

Castle never returns to the 12th precinct, can never again walk down the street where Kate lived and died, he never, ever fills the hollow ache in his heart.

…he could have failed to save her.)

They're going to freeze to death.

At least they'll go together.

Castle returns to consciousness all at once, his vision lagging behind, the edges still smeared and out of focus. He sits up, pain shooting through every extremity, his indrawn breath like a knife to his chest. He's shouting her name, entangling himself in the lines of his oxygen tube and his IV.

A paramedic is at his side immediately, pushing him back, making soothing noises without meeting his eyes.

"Mr. Castle, I need you to relax."

He twists away from her hands, still caught in all the cords. His heart beat is so hard it hurts as he shouts for Kate again, and then suddenly Esposito is there, his eyes red-rimmed and devastated.

Castle takes one look and shrinks back, his hands to his face, trying to hide from what he knows Esposito is going to say. Memory is filtering in now, filling in the blanks, and he fights it, denies it. He can still feel the ice of her hand, the weight of it as it slipped from his.

"Castle. Beckett, she…" Esposito starts, but has to pause, his fist against his mouth.

Castle curls into the fetal position and throws out his hand to stop the unspeakable thing Esposito is about to say. "Stop. No. Just…where is she? Don't…"

Esposito swallows hard and meets Castle's eyes. "I'm so sorry, Castle. God. I'm so, so…"

"No." It hurts to shake his head. Esposito reaches for his shoulder, but Castle flinches back. Accepting comfort means it's real, and that's impossible. He doesn't need comfort because there's no way this is true. Kate is fine. She's standing in the parking lot, wrapped in a blanket, waiting for him to wake up.

But she's not. And Castle doesn't ever wake up. Not really.

The morning of her funeral he leaves before the sun is up and goes to her apartment. He lets himself in with a key procured from Lanie, who handed it over no questions asked, her face crumpled, her hand shaking as she squeezed his. She didn't try to ease his pain, didn't pretend there was anything that could, and Castle was grateful.

Once inside, Castle uses his phone to take pictures of her mother's murder board. Then he carefully packs it away in a box, every picture and newspaper article, every note written in Kate's hand. The murder board was private, an expression of Kate's deepest secret, and Castle figures that when you love someone, you protect their secrets.

That's his secret. That he loved her. He'd kept it from everyone, even himself.

That night, late, half a bottle of whiskey gone and an untouched sleeping pill by his bed, Castle pulls out his pictures and the box. He recreates the murder board exactly, right down to the Post-it notes.

It takes him two and a half years, but he finds the man who killed Kate's mother. When Senator Bracken is finally exposed and arrested, Castle doesn't feel relief or triumph or vindication. He feels empty. Vengeance is a cold, lonely road, but it was all he had left of her, and now he is lost.

Frozen Heat remains unfinished. He doesn't write at all, and Black Pawn has long since canceled his publishing contract. The loss of his livelihood, his writing, should make him feel something, but it doesn't. It's just that the loss of Kate is so all encompassing, has emptied his soul so completely, that there are no pieces left to lose, and Castle can't give what he doesn't have. He's frozen, suspended, and he never gets over it. Over her. He never really leaves that freezer.

Castle never understands why he lived that day when Kate did not. It's arbitrary, irrational and totally incomprehensible. They should have died together.

They should have lived together.

(All worthless if she doesn't live today.)

The sun glints off the scope. A prism of light, oddly beautiful.

Dread punches him in the gut and throws him across the podium before his mind can even articulate the danger. Sniper.He hears the flat, muffled pop as he slams into Kate and takes her to the ground.

"Castle?" She's out of breath with shock, with the impact of hitting the grass. He's too heavy, a dead weight across her ribs and chest that won't let her breathe, but he can't move. His body is offline, disconnected somehow, except for the hand cradling her head. Her hair is slippery and soft against his fingers.

"Oh my god." Kate struggles beneath him, manages to roll them so they are both on their sides. He wants to help her but he's stunned. He can't catch his breath, can't quite focus, and only has a fraction of a second to recognize that the sniper missed, she isn't shot - he saved her - before his whole world tunnels into a vortex of pain and Kate.

She isn't shot.

People are screaming. Above the din Castle can recognize Esposito's voice, but he can't make out the words, and he sounds far away and somehow long ago. The only thing that is now, right now, are Kate's eyes beside him, wide with shock and disbelief. She lifts her hand to cup his face, his blood obscenely bright against her white gloves.

"Castle, just…" Kate presses her other hand to his chest. "Oh, god."

Her voice is shaking. That's how he knows it's bad.

He hopes someone is holding back Alexis. His mother.

(He hopes Alexis will understand. He knows his mother will.)

"Castle…no… what did you do?"

There isn't time to explain. "Kate. I love you." It's explanation enough. "I love you, Kate."

(He's glad he gets to say it. Wonders how long he's known.)

"Castle?"

She's crying, but it's better this way. Any way where Kate lives is better. This leap was self-preservation, not heroics. He couldn't have lived without her.

(Maybe this makes him a coward. He does not know.)

"No, Castle, please."

He hopes Kate can forgive. Coonan. Lockwood. Montgomery.

Him.

"What did you do?"

They don't deserve it, but she does.

Kate deserves to be happy.

He hopes she'll be happy.

(It could have gone like this.)

I should rather die of love

Than to survive without giving all

-Phillip Pulfrey, Madness, Love, Abstraction and other Speculations