It's about the way she looks at him. The way she rests her head on her hands when she's tired. That little smile that pulls at her lips that she so desperately tries to hide every time he makes a joke. It's all those little things that he forgot to notice after a while. The things that he pays no attention to because he's gotten so used to seeing them every day. He took them for granted. He took her for granted. In his usual Rick Castle fashion he forgot to savour the moment as it passed- and in return, he missed out.

He sits quietly in his usual chair and watches her as she mulls over the case. Flipping each page and soaking up every detail with her teeth biting down on that lower lip. It takes everything he has not to reach out and touch her. Touch her arm, he cheek, her fingertips- anything. He feels a connection- a magnetic force that's drawing him to her, and with each passing moment his ability to resist it gets weaker.

"Stop staring, Castle. And close your mouth while you're at it."

Her words break his trance and his mind comes crashing back down to earth. Images of Kate Beckett plummet, but don not cease to exist; for the thought of her has not left him since the moment he first laid eyes on her.

"Dually noted, Detective."

The simple fact that he did not deny it makes her want to break out into a grin but she withholds it. She focuses on the photographs and paperwork in front of her to distract her from the fluttery feeling going on within her. She wants so desperately to feel him. To have him hold her, but she can't let her hearts desire overcome her minds intelligence. She knows all too well the damage a man like Richard Castle can do to a woman like herself. She knows because the damage has already been done.

She keeps her eyes fixated on her work, but her mind is a breeding ground for old memories, and kept promises. It's been four years, four Nikki Heat books, and hundreds of cases since she first felt his stare penetrating her skin, yet her heart still skips a nervous beat every time his hand brushes hers. The teenage girl inside Kate Beckett is begging to be let free. All she wants to do is throw down her pen and spill all the contents of her heart into Castles lap- but she doesn't. It won't mean anything now. Not anymore. This night, this moment in history sitting in the precinct with Castle by her side is the last one she'll get. Her last chance to cherish every second of that goofy smile, and she doesn't want too spoil it by being too honest.

"What time does your plain leave, tomorrow?" she asks casually.

"Early. Around 5:30am." He replies. She nods a silent acceptance to the fact that the man with whom her heart can't seem forget is leaving. He see's the pained expression on her face and watches as she desperately tries to compose herself, and when she looks up to meet his eye he knows. He knows that they were never just friends. He always knew, but not the way he does now.

He opens his mouth to say something, to console her but before he gets the chance she speaks.

"Have fun in Italy."

"Kate" he interjects. She holds up a shaky hand to stop him as she rises from her seat and collects her things. He stands to greet her, helping her slide into her jacket and standing there like a fool while she does it up. Her heart is beating like a drum within her chest, and when Castle brushes her shoulder with his thumb she feels as though she may explode.

"It'll only be a year." He says. He's trying so desperately to fix what's ever so clearly broken, but instead of helping the situation, he only sees her eyes falter once more as the most delicate smiles graces her face.

"You don't have to explain yourself to me, Castle. I'm not your mother." Her attempt to bring light to the situation only makes his heart ache more. Why can't she just say it? Tell him that she's hurting. Why does she have to cover everything up all the time?

She gingerly brushes her hand against his shoulder, bringing it up to rest upon his neck. Her fingers linger there for such a small moment that he almost misses it. She smiles at him once more, those pearly whites as beautiful as ever, yet he's never seen a smile so unauthentic in all the years he's known her. The she turns to leave with her heels clicking along behind her, and Castle finally looses the war that is raging inside of him- and he reaches out to stop her.

"Give me a reason not to go, Kate." He's not so much asking as he is begging, and he prays with all of his heart that she'll hear the desperation in his voice. Suddenly the books, the tours, and the debut of his novel in Rome are unimportant. His career seems extremely irrelevant to his life, because his life is what he's watching walk away.

What happens next is nothing short of unexpected- It's nothing short of amazing. With his hand still firmly holding her wrist she turns to look at him. She's standing so close that he can almost feel the friction their bodies are creating. She leans her forehead against his, hands circling his neck in the most delicate way, and he feels the heat so strongly he almost forgets to breathe.

As she stands there, their bodies touching in the most intimate way they have in almost four years, she feels it- that earth shattering sadness breaking through her already fractured exterior. With her heart breaking within her, she sees all those years of flirtatious banter and sword play coming to a screeching halt. Suddenly, she's no longer a player in their intricate game of possibilities, she's an outsider.

It's over. This is it, Kate. She thinks to herself. With everything bit of strength she has, she tries to keep herself from doing something irrational and stupid- but this time she slips, and the moment she allows her lips to meet his, she's lost.

It's soft and sweet and delicate and all the tension built up over these last four years suddenly seems to drip away. All the longing, desire, and passion they've worked together to create is gone in an instant; leaving them both wondering why they didn't do this sooner. But the release of all these things leaves in its wake a wave of confusion and hurt. Their lips touch, lying chaste upon each other, with only the glue of passion and hurt keeping them together. Neither one moves. Neither one breathes.

With seconds to spare before things turn sour, Kate pulls back. Castle watches her, as she stares back at him. Their eyes dancing a silent dance- a private screening of what is going on inside both of them. Kate; with a whirlwind of sadness and anger due to his departure and her inability to hold herself back, and Castle; questioning what to do next. In an instant everything has changed. The somewhat childlike relationship that they'd been maintaining has matured and suddenly they're dealing with something much more real; much more serious.

He's heard stories about her past boyfriends, but has heard nothing about anything meaningful. Nothing that says to him that she knows what it means to have her heart completely broken- she's only had it seriously damaged. But the brilliant eyes of Kate Beckett have never been so full of emotion, and the chuckle that escapes her already trembling lips confirms his suspicion; he's the first man to break her this way.

"Go to Rome, Castle. Have the time of your life." She touches her fingers to her lips as she turns to walk away. When she reaches the elevator, she turns back to look at him, and although he's at a distance, he can see the tears that had been threatening to fall all night make their debut. And as the doors close, somewhere in the back of his mind he hears her words as she spoke them that day all those years ago to Mike Royce;

"I was in love with you."