It's not a date.

It feels like a date.

She's sitting in front of him, a smile on her face, her cheeks stained a soft shade of pink that matches her milkshake.

He's never seen her like this, so open and…sweet. Without the weight of being a woman in a man's word weighing her down. Without the armor she's built for herself protecting her, disguising her every move as something it isn't.

Sure, he's seen her outside of work, but this is…different.

This is her. A different version of her, a different layer. The woman sitting across the table, unknowingly driving him crazy every time she pops a french fry into her mouth and every time she licks the slightest bit of strawberry milkshake off her lips.

And they talk. About nothing and everything all at once. About the case and the boys and Alexis and his mother, about the failed dates from earlier today.

Never falling silent. The well never running dry.

So, long after his burger is finished and his last few sips of milkshake have come up with nothing, he doesn't want to leave. And she doesn't make a move to, even though it's late and that bath she mentioned earlier—

Okay, he really cannot be thinking about her in a bath right now.

Instead, he focuses on that smile and the passion in her voice as she tells him about her time in Kiev.

The meal has long since been finished, any reason to stay dissipating with every second that ticks by, and yet they stay. For the company, he supposes. For the pleasant conversation that has him leaning over the table and humming his interest.

It feels like a date when she turns to glance at the clock and realizes what time it is, that they've been sitting here talking for much longer than she probably intended.

It feels even more like a date when she hides her blush behind her hair, offers him the smallest of smiles and tells him she has to go.

Her eyes are sparkling with joy and something else and he really wants to kiss her.

But it's not a date, so he just nods and watches her leave.

It's not a relationship.

They do it again. And again.

Midnight dinners at Remy's turn into regular occurrences after they solve a case, quiet conversation, new tidbits of information being revealed every time. He stores away each one, returns everything she gives by telling stories about his mother and Alexis whenever she tells one about Ryan or Esposito.

And then it becomes more than lunch, but rather the unspoken agreement that they do things together. If she needs a drink, they go out for drinks. If he's supposed to be writing, she offers him not only a reason for, but a method of procrastination.

She stands closer, rolls her eyes just as often.

When the teasing escalates, so does his pulse. As she drops hints about leather cuffs, and metal ones, too. As she leans across her desk, voice falling an octave, and drives him crazy with the roll of her tongue over each and every syllable, only to lean back, leaving so much to be wondered.

So much to be desired.

But it's not a relationship, not when she goes home to her empty bed and he goes home to his. Not when the brush of his fingers against hers is the most contact permitted.

Not when he's standing on the street, cellphone in hand, staring at her building engulfed in flames.

It hits him hard, like he's suddenly landed.

He's been falling, hard and fast, this entire time, and she's still standing at the top of the cliff.

But he runs into the building and breaks down her door to carry her out. She's still breathing. Her heart's still beating. Her voice cracked, but still there.

The paramedics check her, give her a clean bill of health and every single one of his tense muscles seems to relax for just a second as he stares at her smile.

He's falling in love with Kate Beckett.

So, when she tells Montgomery she doesn't have a home, he gives her one. When he finds her father's watch in the rubble, he has it fixed. When she cooks breakfast in his kitchen, for his family, his heart stutters.

And when she crawls into his bed one night, mumbling something that sounds oddly like you're alive, you're alive, and curls herself around him, he's powerless to push her away.

It's nothing.

They never label it. They never even talk about it.

She spends three weeks at his place, falling into a routine, cooking breakfast on her days off and dinner when she, by some twist of fate, gets home early.

There's something about the way she leans in towards him when they watch a movie, about the fact that his mother so easily gave up her usual seat at the kitchen table, about the mornings he wakes to find Alexis and Beckett talking in the kitchen that makes the loft feel even more like home.

They fall into a routine easily, from the very first night. During the day, they're friends, partners, bumping shoulders as they do the dishes side by side, playing off each other as they give Alexis what must end up being horrible advice. But at night, when darkness falls, and every time he closes his eyes he sees the blast he couldn't save her from…

That's when they're more. When she curls up against him and thanks him for keeping the nightmares at bay as though she doesn't do the same for him.

And he can't complain, he really can't. Because he's falling in love with her.

So, one night, he dusts a kiss to the top of her head, and his heart swells when she doesn't flinch. And on another, she presses her lips to his cheek for half a second before settling in his arms.

The day before she leaves, she straddles his lap and presses her lips against his hard, and her tongue slips into his mouth before she pulls away, cheeks bright red, and curls up against him like nothing happened.

Like nothing's been happening.

The next morning, she tells him she found a place. Within a day, she's gone.

And he misses her. Enjoys movies less, stupidly hates that his mother is sitting next to him at the kitchen table again, despises finding Alexis alone, reading in the morning. And at night…

He thinks of asking her to come over, of inviting her to a movie or to dinner, hoping she'd stay the night, maybe kiss him again. He debates doing it every time they part at the precinct, when she blushes as though memories haunt her, too.

He's about to do it.

Then Demming shows up. The handsome robbery detective that seems to steal her heart. He flirts, and she flirts back. He smiles, and she smiles.

Suddenly, he's standing on the sidelines, at the bottom of this cliff off which he fell for her, watching her fall for somebody else.

It hurts, but he can't say anything, can't ask his place or stand his ground. Because he has no ground to stand, no place to have. He never asked for any.

And yet he's mad, so he tells her to go on a date with Demming, if she likes him so much.

She looks just as mad as he feels, but she listens.

It shouldn't hurt. After all, they've never been anything. It was never a date, it was never a relationship. It was nothing.

It shouldn't hurt. But it does.

It's something.

Maddie's words break him out of it, this little pity party he's put himself in since he saw Kate walk off with another man.

You have the hots for Castle. You want to make little Castle babies.

And all he can picture, all he can feel is the way her thighs framed his hips, her fingers combed through his hair, her lips pressed insistently against his. The kiss that was everything he'd wanted for…months, but felt strangely like she was saying goodbye.

Well, when she walks out of the interrogation room, cheeks stained pink, he can't just let things remain unsaid.

He can't let that kiss be goodbye.

His fingers curl around her wrist, refusing to let her go when she tries to pull away, and he leads her out of the bullpen, down the hall to a stairwell that he knows is often vacant. He doesn't let her go, though, even after they reach their destination.

When it comes to romance, he's noticed, her fight or flight instinct tends to send her running, but he won't let her run away this time.

He turns to her. She's fuming.

"What the hell, Castle?"

And he says the first words that come to mind.

"Four months."

Her features soften, the angry furrow of her brows fading to one of confusion, of curiosity as her lips quirk with what must be a response that she can't come up with.

So he takes a step closer to her, reaching out with his free hand to splay his palm across her arm, thumb tracing the sharp angle of her shoulder.

"Four months ago, we went on our first date."

His voice is shaking. Even he can hear it, the slight quiver of nerves that robs stability from every word, every syllable. But his eyes stay locked on hers, gaze unwavering as he stares into the hazel of them, past the flecks of green and gold that he loves so very much.

"It wasn't a date. But it was. We talked for too long, flirted too much and sat too close for it not to be. And Kate, watching you walk away from that table, all I wanted to do was kiss you."

She blinks, opens her mouth and the snaps it shut around words she doesn't say.

"And then it happened again. And again. We went out for lunch, for dinner, for midnight snacks. For drinks that had you open and free and giggling, and every time I just wanted to…tell you. To be more than what we were."

It's stupid and sappy, something he would write in a book, or read in someone else's. But words are his specialty, and quite possibly his only way to her stubborn, closed off heart.

"Then your apartment blew up, and for a moment I thought you were dead, but you weren't. Instead, you moved into my loft, my home, and Kate, you made it feel more like home than it ever had. For three whole weeks, you were there. For two of them, you slept in my bed, in my arms. And then Demming shows up and suddenly it's like we're nothing."

She's shaking now, muscles quivering under his hand. He has no doubt that if he was to let go, she would run, and he would never see that smile he loves so much again.

So he doesn't let go. And he keeps talking.

"It made me realize something. It made me realize that we are nothing. We always were. Because I never asked for more. Because I'm the one who uses words for living and yet I couldn't find the ones to ask you out, or to tell you how I feel. Hell, I couldn't even ask for a second kiss. Because we were nothing. And I don't want us to be nothing."

She looks like she wants to slap him, but she doesn't. Instead, she shakes her head, violent and almost desperate and he just now notices the tears in her eyes, feels the pounding of her pulse underneath his fingers around her wrist.

"Stop."

But he can't. Not now.

"Castle, please, just…stop."

She swallows, still shaking her head, her pulse impossibly fast. And for the first time since he fell for her, he realizes she fell for him, too. But while he's been trying to hide it, trying to tamper it to avoid the inevitable disappointment of finding out she doesn't feel the same way, she's been running from it, trying to shield her already scarred heart from further damage.

And now they're standing in a stairwell, hurt and angry when they don't have to be.

Because he fell for her. And she fell for him. And they're finally finding each other at the bottom.

"Let's be something, Kate."

It's a whisper, hesitant, nervous.

But in one of the precinct stairwells, she smiles, and answers him with a kiss that feels nothing like goodbye. And somehow, standing in the middle of the mess they made, it's perfect.

It's everything.