Nothing in his academy training has prepared him for this moment, even if a lifelong love of ghost stories and urban legends has set him up perfectly. He's stunned, though probably less affected than the woman standing – floating? – in front of him, and he's not sure what else to say beyond the bombshell he's already dropped on the hardwood floor of his bedroom.

Is he supposed to apologize? Offer condolences? Congratulate her?

He sort of wants to hug her, but he doesn't know how that works between the living and the dead.

"I can't be dead. That's just stupid."

His eyes flicker back to hers and he concentrates on replacing pity with something more reassuring. "Well, I don't know about 'stupid.' Definitely wild, though. And the beginning of one hell of a murder mystery novel, so we could probably look into selling the rights if we want to make some quick cash. Although I guess you don't have much use for money now, so I'm all alone on that one."

"Shut up, Castle. And let me see your phone again."

They're only about a foot apart now and he can't find any obvious sign that Beckett is not a living and breathing NYPD homicide detective; however, when he tries to give her the phone, it lands hard at his feet and suggests the absurd is becoming a little less so.

Both flinch at the crack of the case on the floor, but he manages to speak first. "You couldn't hold onto it, could you? I mean, did you even feel it?"

Beckett is on her hands and knees, probably grasping for answers as much as the chance to pick up his phone, but swiping at the device gets her nowhere and she finally growls her resignation and stands to face off with him again.

"There's a legitimate explanation for this."

"You not being able to hold a solid object? Yes, the explanation is that you're a ghost," he affirms. "I'm a little confused about how you keep your clothes on because it seems like they'd be subject to the same supernatural laws and would just sort of float to the ground, but I'll admit I'm not totally up on the details of this undead stuff. It could be a decency thing, I guess. Naked ghosts would be far more distracting. But that's why you don't have your gun or your phone or anything else. Anything unrelated to your appearance seems to have—"

"Jesus Christ, can you stop talking for two seconds? You're like a nine-year-old on a sugar rush." When she paces across the room, Castle can't help but notice there's no thump of frustrated footsteps, the silence haunting. "Stop with the how-to-dress-a-ghost-theories and tell me what you found on your phone."

He doesn't bother to pick it up, his search for her name enough to remind him of why it was familiar in the first place. "Like I said before, I've only been in New York for a few months, so I was still in L.A. when it happened. But it was big news around here and some of the guys were still talking about it after I arrived. Your captain – Montgomery, right? – he was killed in the line of duty, some big standoff in an airport hangar from what I heard. But you already know that part, huh? Anyway, you were giving the eulogy at his funeral when a sniper shot you. The scene was chaos, of course, all those cops on hand, but there wasn't much anyone could do and you died in the ambulance on the way to the hospital. The youngest woman in the NYPD to make detective gunned down, the killer never caught. You made some pretty spectacular headlines and more than a few still hang in my precinct; I can't imagine what it's like in yours. Probably a damn shrine to both of you."

Beckett's shaking her head, willing his words away, but he's spent enough time in interrogation rooms to be able to read people and there's little doubt the story of her death is one she knows too well. And he'll admit to some surprise at that; just minutes before he would have pegged her as the kind of skeptical hard-ass who would break long before she'd bend, evidence outweighed by the most basic logic that the dead and gone are just that. It makes him wonder how long ago her subconscious began to recognize that she hadn't survived that May afternoon. How many silly objects couldn't be held, how many people never acknowledged her presence. How ready she was for someone to confirm that terrible truth.

Vincit omnia veritas. Yeah, Beckett probably feels pretty damn conquered right now.

The abuse of her lip continues and a shaky hand presses against the center of her chest; Castle doesn't remember those details, but he assumes she's covering the fatal wound she's prefer to deny. When she finally speaks again, the sharp edge of her voice has dulled into something he doesn't like.

"I remember speaking at the funeral. Wanting to give Montgomery the goodbye he deserved, and hoping I could someday lead my own precinct with the same warm, quiet dignity with which he led his." She swallows something uncomfortable, but he won't pretend he knows what it's like to reflect on being shot while burying a role model. "I don't—I wish I could remember what happened next, maybe I could help us solve this thing, but it was all so crazy. I'm not even sure I'd say it hurt. Everything was too bright, too loud…the sky, the sun, the crowd—"

Another abrupt stop has him leaning forward to console her until he realizes his touch will have no effect at all; the pressure of his hand would go unnoticed, the intent behind it falling ridiculously short. All he can do is wait while she finds a way to choke out the rest of her story, everything on hold while she suffers a version of grief darker than most he witnesses, one that carries the guilt of being the one who died, instead of the one left behind.

"My father," she sobs. "Oh god, Castle, what the hell did my father have to see? There was so much screaming, and he had to be one of them, but I don't remember. Why don't I remember? Why couldn't I see anything but the sunlight?"

Castle shrugs, painfully aware he has nothing better to offer. "I don't think I heard anything about him when people were talking about it. I know the other guys you mentioned—"

"Ryan and Espo."

"Yeah. I guess they were standing up there with you during the eulogy, so they got to you first. And one of the M.E.s?"

"Lanie. Oh my god, Lanie. She's gonna kill me."

It's not funny. None of the scene playing out before him, nor the memories being shared, are any reason to crack a smile, much less do anything else. Still, her own terrible choice of words snaps her in half and she doubles over in hysterical laughter, the sound light even as it's clouded by the sight of tears streaking her too-pale cheeks.

He lets her ride it out, this wave of sadness and fear that he can't fully comprehend, watching when she finally catches her breath and lowers herself to the floor. It's another several seconds before he steps past her to slide down his bedroom wall and land with an uncomfortable thud, as close to her as he dares while she's this fragile, a stranger he can't touch but could probably break.

"If you make a list of people you want me to visit, friends or family or coworkers or whatever, I could do that."

"Yeah, that would go over well, I'm sure," she mutters. "Let them know the ghost of Kate Beckett says hello and hopes they're doing well in the wake of her untimely demise."

It's Castle's turn to growl. "That's not exactly what I meant. I'm trying to help here. I can just swing by your precinct, see how they guys are doing there. Maybe ask about the M.E."

"And my father?"

"Yeah, of course," he answers. "Whatever you want. Whatever I can do."

They're quiet for quite a while after that, the ebb and flow of wordlessness sweeping them up again, but the subtlety of each breath, the banality of his heartbeat have somehow become distracting, reminders of the chasm between them. He's been unable to look away, content to study each new emotion rippling across her face, even as he hates himself for wanting to remain close to her pain. And Castle is growing tired, but he can't fathom sleep when there's still more to learn about this beautiful stranger.

Tired.

Sleep.

"Wait a minute, Beckett," he murmurs, unwilling to startle either of them after so many minutes of silence. "You were killed four months ago, so where have you been sleeping all this time? Or, I guess, you probably haven't been sleeping per se, but you had to be spending your time somewhere, right?"

"I've been at my dad's cabin, mostly sitting by the lake and soaking up the summer sun. Recovering, or so I thought. Nobody else was up there, so it felt right, like a wonderful chance to be alone and figure out my shit. In hindsight, it seems so obvious; I don't remember feeling any pain, don't think I ever ate or drank or showered or slept. But when I was there, none of that mattered. It was just sunrises and trees and the dock I'd jumped from a million times as a kid. Trails I'd walked, bird songs I knew by heart. It was perfect, and maybe that should have been my first clue that everything was wrong."

He huffs, somewhere between delighted by her recollection and very, very sad. "You must have been a damn good person to earn yourself purgatory with a view."

"Depends on who you ask, I suppose. But now my purgatory has led me here."

"Still not a bad view," he teases, nudging her with his foot though neither of them can feel the contact.

She arches an eyebrow, but her tone is softer than expected. "No, it's not. But why am I back in my old apartment? Is it because it was my home? Did I leave something behind? Am I just looking for a way back to the life I had?"

Castle holds her stare, hoping there's an easy answer in his eyes or hers, a way to make this all better. He'd meant what he'd said earlier, he does want to help her in any way he can, but what can he possibly do for the dead woman by his side? She has so many questions and there's such little he can offer in response. Hasn't her story already come to an end?

And then it occurs to him that perhaps it hasn't ended. Her story. Her captain's. Her mother's. Three lives cut tragically short, but three stories yet to come to a close, the final chapters still unwritten. He knows then that she hasn't returned to her apartment because of the building itself or any miscellaneous object within.

"It's because of me."

Beckett scoffs. "Come on, I already conceded that you're not terrible to look at, but you really want to argue that I've held on to some version of my human form just for the chance to hang out in your bedroom?"

"While I like the sound of that, it wasn't my point," he smiles, excited by a case for the first time since his divorce. Since long before that, really. And he's aware they barely know each other and she's unlikely to want to work with him, but he's also aware she doesn't have much choice. "I meant that I can help solve all three murders. You said you were after justice with no plans to back off no matter how dangerous it got, and lucky for you, I'm just as crazy and stubborn."

"Yes, lucky for me, a total stranger ready to fight my battles," she sighs, the pause that follows almost painful. "Okay, fine, but I don't know who took over at the 12th, so even though I think I could get Ryan and Espo on board, I'm not sure they'd be able to sneak around with a brand new captain."

"What about going to the new captain for support? A full team on this?"

"No way," she snaps. "We're talking high-level conspiracy here and I don't trust anyone else on this. I don't even like putting the boys in the crosshairs, so maybe they shouldn't be involved. And I don't really know how the hell you can go at it alone."

"I'm not alone. I've got you."

"So, what, you think we're going to be partners now?"

"Of course not," he answers. "You can be my plucky sidekick."

"The plucky sidekick always gets killed, Castle."

He's pretty sure she's setting him up, but he can't resist. "Well, then, I guess there's nothing to worry about."

"No, I guess not," she replies. "But I think I like the other idea better."

And with that, she holds out her hand so they can shake, the somber smirk on her face enough to acknowledge that they won't be able to touch the way anyone else would; his nod recognizes that harsh reality, a world he doesn't understand, but has been quick to accept.

"Partners then."

A/N: All the gratitude in the world to both M and A for talking me through this entire fic, supporting me from afar and allowing me to use them as needed. I'm immensely fortunate to have them on my side.