Your feet will bring you to where your heart is.

~ Irish Proverb

Kate chews anxiously on her bottom lip and watches the red LED numbers flash on the wall, can feel her pulse spiking with each silent flicker. The bell chimes and she's out of the elevator as soon as the part between the sliding doors is wide enough to accommodate the width of her body; is halfway to their front door before she can even suck in a full breath.

She stops outside the loft, her fingers wrapped tightly around the door handle, the smooth metal cool against her palm. She knows what's on the other side and though she's been moving toward it all day she finds herself needing a moment to let it sink in. Castle is proposing to her. Tonight. Now. They've talked about marriage at length over the past few months, have been brutally honest with each other about their expectations and needs. She voiced her fears about his divorces and he explained his need to be certain before even considering marriage again. She's known this day was coming, has been anticipating it since she caught him looking at rings on the internet while he thought she was napping one rainy Saturday afternoon in March. But the reality - the knowledge that all that stands between her and marriage is a four inch thick slab of wood and metal - gives her a moment of pause. Makes her chest ache with so much love and want that she's certain her ribs will splinter from the pressure of keeping it all inside.

Castle is waiting for her. With a ring and more than likely a self-satisfied grin. Her heart flips as the image of his face floats through her mind and she pushes the key into the lock, letting out the breath she hadn't known she was holding as it slides home and the handle twists, the silver tongue slipping into its nest inside the door. Pulling herself up, she shoves the heavy door open and steps into the loft, finds -

Nothing.

The apartment is dark. Empty. She'd been expecting dim lighting, every available surface strewn with gently flickering candles and fragrant flowers, the soft strains of something romantic and jazzy floating on the air. She'd been expecting him to go completely overboard. Her keys and bag clatter to the side table as she steps further inside and closes the door, a streak of mild disappointment zipping through her chest. She doesn't need the romance. It's not in her nature, really. But it is in his and she can't help but wonder -

Shaking off the doubts, she slips out of her heels and smooths her hands through her hair. There is nothing to wonder about. Nothing to fear. He's been planning this for months. He left a trail of his love for her across the city, recruited their friends and family to help guide her through their past and back to him.

He wants to marry her.

The clacking of keys catches her attention and she moves into the loft, drawn like a moth to the gentle yellow light spilling out of the open bookshelves that make up one wall of his office. Grinning, Kate slips across the living room, her breath quickening as she catches sight of him through the ajar door. He has his feet up on his desk, laptop sitting on his thighs, fingers feverishly flying across the keyboard. She smiles and wonders what he's working on, if he's typing out a final letter or writing this love story of theirs for the rest of the world to see. She always claimed she wasn't Nikki Heat but late one fall night, months after they started to date, she had quietly admitted that she wanted to be; she wanted to be that version of herself, the one he had created. It fueled her, made her want to be more.

He made her want to be more.

"Detective Beckett, are you ogling me from afar?"

She can't help the smile that blooms across her lips, fills her entire body with warmth. She steps into the room, lifting herself onto his desk. Her feet swing and she feels like a child, carefree and innocent and so exceptionally happy that she doesn't know whether to laugh or cry.

"Don't flatter yourself, Castle."

She bites down on her lip and looks around the room. It's not that she doubts his proposal, but this isn't him. He's loud. He pulls ridiculous stunts like sending her across the city on a scavenger hunt; enlists random strangers to gang up on her during a paintball battle. He loves crazy gestures even if she -

Oh.

Castle sets the laptop down on the desk and rolls his chair closer to her. Her feet rest on his thighs and he runs his hands over her calves, light and teasing. "Thank you for going along with everything today. I know it's not you but -"

"I loved it," she interrupts. "It was - Castle, it was amazing."

"How long did it take you to figure out what this was really about?"

Kate lets out a laugh. "I'm a detective; how long do you think?" Castle smiles at her and it's overflowing with everything he's given to her in the past year of their relationship, the four years before that. She drags her fingers through his hair, tries to find the words that he's always managed to be so much better at. "Those letters. Castle, I - You are the most amazing man. You annoy the hell out of me sometimes-"

"Sometimes? Are you being generous because you know I'm proposing?"

The words fall from his lips so easily like it's nothing and everything at the same time and it's incredible to her how much she just loves him. "No, I just forgot for thirty seconds how aggravating you can be. That's my mistake."

It's his turn to laugh, blue eyes sparking with love and joy as he stares up at her. "Glad I was able to bring you back to reality so quickly. Wouldn't want you agreeing to marry me while harboring any illusions about my ability to drive you crazy."

She swallows the sarcastic retort that bubbles up in her throat. The fact that her acceptance is a foregone conclusion for him makes her heart swell. It's taken them so many years, so much heartache, to get to this place and his trust in her is almost as awe inspiring as his love.

Her feet slide off his lap as he rolls the chair back and stands, his shirt and pants wrinkled from hours spent in front of the computer. Grabbing her hands in both of his, he tugs, tries to dislodge her from the desk. Kate shakes her head and tenses her arms, pulling him toward her; she wraps his arms around her waist before snaking her own around his and leaning forward to rest her head on his chest. His heart thunders under her ear, a counterpoint to her own syncopated rhythm. She holds him tightly, hands coasting over his back as she lets the delicious anticipation that has flooded her body all day slip away and settles herself in the moment. She wants to remember this, wants to be present.

"You okay?" His breath rustles over her crown, soft and warm, and she nods, her nose brushing against the worn cotton of his shirt.

"Yeah." She loosens her grip and leans back, smiling up at him; he sweeps a hand over the top of her head, his thumb lingering at her temple. "I'm good."

Kate lets him help her off the desk, his hands broad and warm on her waist, and lead her over to the overstuffed leather chairs in front of the bookcase. Castle aims her toward the chair nearest the window, the one he knows is her favorite. She loves to sink into the deep seat, her legs tossed over one arm, the light from the bay window spilling perfectly across her body, leaving her warm and comfortable. It's her favorite place to read and nap; to curl up and watch him while he works, his body swaying to some internal melody as he spins their life into bestselling fiction.

When she's seated, Castle moves to the opposite chair, pulling it around to face hers. His fingers tremble slightly as he reaches for her again, an airy laugh caught in his throat. "I'm nervous," he states, shaking his head. "Didn't expect that." Kate smiles at him reassuringly and tightens her fingers around his, her chest humming with emotion.

Sucking in a deep breath, he leans forward, forearms braced on his thighs, both hands clasped tightly around her left. "I sent you all over Manhattan today because I wanted you to remember each and every place I fell in love with you. There are times when I look back on everything and think it was the easiest, most natural thing that has ever happened."

She lets out a laugh; she doesn't mean to, but it bubbles up in her chest, nervous and overwhelmed and she rubs her thumb over his. "Easy?" she asks with a tilt of the head, the laughter turning into a full blown smile.

"You do know you're not supposed to interrupt the proposal, right?"

Kate holds up her free hand in surrender. "Sorry. Go ahead."

"Then there are other times - most of the time - where I look back and realize that it was the hardest I ever worked for something. I think about it, try to imagine where I'd be if Harrison Tisdale used some other author to cover up his murders, if I had never met you, and I can't." She watches the blue of his eyes shimmer and pool with unshed tears, hears the hitch in his breath as he continues, paints a portrait of his love with words she ever wants to forget.

"I'm not the same man I was five years ago. I'd like to think that I'd have made it here on my own eventually but I honestly don't know. I spent my life indulging in romantic fantasies, searching for my other half but you -" He scoots forward on the chair, his body pressing forward with the weight of his words. "You opened my eyes, Kate. You made me realize that I wasn't missing half of anything; showed me that I was already capable of being the man that I wanted to be, all I had to do was be willing to work for it. You see me and love me for who I am and you make me want to be more."

Castle pauses, his eyes slipping closed. She gives him the moment, allows him to gather his thoughts in silence, her fingers twisting tightly around his.

"The truth is I could have written a thousand more letters and it would never be enough. For all the words I have, and we both know I have more than anyone could ever need," he chuckles and she leans into it, lets the sound of his laughter fill her up, "I don't think I will ever find the ones to tell you how grateful I am that you came into my life. How damned lucky I am that you love me. How much I -" He chokes to a stop, his hands clutching at her.

Tears slipping freely down her cheeks, Kate slides forward in her chair and reaches out, lays her fingers gently on his cheek. "I'm lucky too," she whispers around the knot of emotion lodged in her chest. "So very lucky."

His lips are warm and damp against hers, a fleeting caress. Kate keeps her eyes closed when he pulls back, her hand slipping from his cheek and a happy sound humming in her throat.

"Kate."

He's on his knees in front of her when she opens her eyes, a sparkling diamond grasped between his thumb and index finger. She chokes on a sob, her ribs aching with the frantic pounding of her heart. His eyes track her as she slides down to meet him on the floor. She doesn't want to be above him. Not for this. They're equals. Partners.

"Kate," he repeats, voice thick with tears. "I love you. Will you marry me?"

"Yes." It's instant, the answer pouring out of her lips without conscious thought. "Yes."

Castle slides the ring on her finger, the cut of the diamond catching the light. The stone is moderately flawed yet somehow incredibly flawless and she knows there's meaning behind this. Tonight - when it's quiet and dark, nothing left in the world but them wrapped up together in their bed - she'll ask him about it and he'll continue to spin their story, the whirlwind of events that have led them here.

She can feel the band around her finger, the residual warmth from his skin radiating out of the metal and seeping into hers. She'll have to tease him later about how many times he's taken it out today, stared at it and hoped that it was right. But for now she leans forward, touches her lips to his, foreheads pressed together.

"Did you bring my lucky pen from Remy's?"

The question is unexpected and Kate laughs, happiness pouring freely from her lungs. She leans back against the chair, the ring catching in her peripheral vision. "I think you already got lucky," she answers, wiggling the fingers of her left hand.

"You forgot, didn't you?" He sighs with mock annoyance, shaking his head. "I write you all these letters, Beckett, and you forget my pen. I guess you're going to have to make it up to me."

"I just agreed to marry you. Huge sacrifice on my part."

"Please," he huffs, pulling her into his lap, arms wrapping tightly around her waist, "we both know you've been dreaming about this moment since the day we met."

"You wish." She leans her head against his shoulder, her lips brushing softly over his neck. "Thank you for this. For today. It was perfect."

"Well, it was no midfield during game seven of the World Series but I think it'll be a sufficiently romantic story."

Kate smiles. "Big and intimate."

"I know what you like," he says, lips pressed against her forehead. "And speaking of," his hand runs up her back, fingers warm and strong, "how about we move on to the intimate portion of things. I've been thinking all day about seeing you wearing nothing but this," he runs a thumb over the ring sparkling on her left hand, "and a smile."

Laughing, Kate unfolds herself and stands in front of him. Her heart still beats wildly in her chest, elation swirling like wildfire through her veins. Castle stares up at her, a wide grin stretched across his face and she holds her hands out for him. "I hope you're prepared for this, Castle. I hear engagement sex can be pretty spectacular."

He grips her hands and stands, pulling her up against his chest, love and desire swimming in his eyes.

"Kate," he whispers against her ear and she shivers, her body melting into him, "you have no idea."

fin