A/N: This is a short post-ep for 6x17: 'In The Belly of the Beast'. As a result, it contains spoilers for that episode. Knowledge of any episode that aired before that date is assumed.

My sincere thanks to Chanhoed for allowing me to borrow her beautiful montage for the cover art.

"Your task is not to seek for love, but merely to seek and find all the barriers within yourself that you have built against it."

- Rumi

The Letter

The small brown envelope arrived in the mail a week later, sealed with CSU tape and marked for Richard Castle's attention.

Kate was at the precinct that morning - half days for a week mandated by Gates - the Captain's order masquerading as some kind of a reward for stepping up when she wasn't even supposed to be on-duty. But they both knew what Gates really meant by this loosening of the reins – that she was easing her best detective back in gently after the disastrous Narco op that came dangerously close to becoming the perfect trigger for a severe episode of PTSD at the very least, if not a deadly, life-ending catastrophe at the extreme end of the scale, had Kate not been such a great cop.

In all honesty, Castle was alert to the potential for some blowback too. He sat up the first night they got home from the precinct while Kate slept, resting against the headboard beside her, waiting and watching for any signs of nightmares or flashbacks, even symptoms of head trauma.

Kate woke at 3am the next morning to find him slumbering while still sitting upright beside her, and she had to physically drag him down beneath the covers to wrap himself tightly around her so that she could fall back to sleep, needing the powerful crush of his body surrounding hers to ward off the bone-deep chill of icy-cold water and the even more chilling flashbacks.

Since then they had barely spoken about the events of a week ago, both too afraid what it might mean for their family now that Senator Bracken's debt to Beckett is paid. Are all bets off? Would he come after her now that nothing but his thirst for power stood in his way? The kind of money he has behind him and the power it can buy is dizzying, could make any man feel omnipotent, invincible, beyond the reach of normal societal bounds and due legal process. The very thought of Senator Bracken's state of mind, if he is indeed 'Lazarus', was terrifying.

Castle walked to the kitchen counter with his stack of mail, flicking through the small pile of credit card statements, promotional offers, the odd fan letter, and a few bits and pieces addressed to Kate and his mother. He paused when he reached the small brown envelope, his brow furrowing when his finger stuck to the line of tape sealing the flap on the underside, and then he turned it over and saw the tiny repeated print running along the seam.

He topped up his coffee and sat down at the island to open the envelope, the rest of the mail forgotten, pushed off to one side. Inside the envelope, he found a folded piece of cream notepaper and a second, slightly larger note scrawled on NYPD Crime Lab headed paper.

The larger note read:

Dear Mr. Castle,

Following an exhaustive forensic search of the property where Detective Beckett was held during her recent joint operation with Narcotics, we found trace evidence which led us to uncover the enclosed letter, which was concealed behind a vent in the wall of the bedroom where Detective Beckett was sequestered. We quickly ascertained that the letter was addressed to you, and so, on Detective Beckett's instruction, we have forwarded it on.

Please excuse the evidence tape sealing the back of this envelope. Our office has run out of Scotch tape and with budget cuts restricting the purchase of office supplies, we're making do for now.

Best wishes,

Matt Gerrard, Senior Crime Scene Technician.

Castle read the short note a second time, slowly. His writer's imagination drew fast, frightening, fiercely detailed sketches of the room where Kate was held, as his brain scrambled to ascertain what trace evidence they could have found that might have led them to a letter she thought to write for him and then had the presence of mind to secrete from her captors.

She truly is amazing, he thought, not for the first time and certainly not for the last.

He took another sip of coffee and then set the CSU tech's explanatory note aside to reach for and read the real thing.

The stiff, cream notepaper was folded up small and tight. He paused before unfurling it, his palms beginning to sweat, his fingers trembling slightly. He was acutely aware that things once seen or read or even overheard could not be eradicated from memory – not fully. So for a second or two he considered just sliding Kate's letter back inside the brown envelope and putting the whole thing in his safe, so that he'd know where it was if he ever wanted to read it.

But then he is a writer, an inquisitive writer who has always poked around, needed to know the full story, even if the subject of his research wasn't always keen on his probing, searching ways. And so finally, curiosity got the better of him and he began to unfurl the sheet of paper.

The first thing he noticed was the smudge of blood smeared along the top edge of the paper, the slight impression of a partial fingerprint, and he swallowed thickly, knowing all too well whose blood this must be.

The second thing he noticed was the handwriting – it may be jerkier, hastier, less carefully laid down than usual, but this was Kate's cursive and he would recognize it anywhere.

He took a deep breath, rubbed a hand over his face and then looked down at the page to begin reading. Tears welled in his eyes within seconds of seeing his own name, and he swiped at them with the back of his hand to avoid damaging the page, before he plunged right in and read it through from start to finish without pausing.

Dear Rick,

I don't know how much time I have even to write this letter. What I do know now is that I am in this and the only way I'm going to make it out alive is to see this through.

I'm sure everyone is looking for me and if they figure out I was here CSU is going to search this house. They are going to look for blood and they will find it, which will lead them to this letter.

Babe, it's your letter, and I hope you never have to read this, that I can tell you all of these things in person. But if something happens and I don't make it, I need you to know that our partnership, our relationship, is the greatest thing that has ever happened to me. You're an amazing man and I love you with all of my heart.

Always

She left everything on that page, kept nothing back, everything she felt for him and for the relationship they had built between them over the years; the life they now shared. She had told him at the precinct, when they first got a chance to be alone, that he was with her the entire time, that it was thoughts of him, their wedding and their future together that kept her going throughout the entire ordeal; kept her fighting through the nightmare of fearing for her life, of torture, of literally fighting for breath near the end.

Kate wrote this letter because she almost died; he can see that so clearly. It is a love letter, but also one of goodbye. They haven't really talked about that period of lost time since the moment their bodies collided in the seconds after she exited the precinct elevator at a run, throwing herself into his waiting arms. He had held her for over a minute, his face buried in her tangled hair, his arms banded tightly around her back, holding her upright though extreme exhaustion and gravity tugged at them both.

Captain Gates had stood discreetly to one side, waiting, and Castle could have sworn she'd have happily made it a group hug with very little encouragement from him, given the look of utter relief and joy on her face at seeing her best detective come back safely.

He sipped his coffee and read the letter through once more, slowly, quietly, savoring each word, every curl, loop, dot and slant, and then he set it down on the countertop so that he could dry his eyes with the tails of his worn flannel shirt.

He was supposed to be editing his latest chapter while Kate was at the precinct, but he found that he couldn't concentrate, couldn't wait even another minute to see her. So he grabbed his wallet, cell phone, house keys and a jacket and headed for the front door.

He couldn't remember hailing the cab as Kate's words played on a loop inside his head; fragments of the letter repeating round and round to form the most amazing soundtrack to his short journey across town.

"…I am in this…"

"You're an amazing man."

"Our relationship is the greatest thing that has ever happened to me…"

"I love you with all of my heart…always."

Castle was dancing on the spot with impatience by the time the elevator ascended to the Homicide floor at the Twelfth, and then he bolted, just as Kate had done, as soon as the doors opened.

He almost ran straight into the chests of two enormous Uniforms, managing to slow and dignify his pace at the very last second, though the men still stared suspiciously at him on their way past.

He peered through the wire mesh surrounding the bullpen, his stride slowed down to that of a power walker in Central Park. And then he saw her and all bets were off. He approached from behind, holding a finger up to signal to Ryan that he shouldn't give him away, before he leaned down to wrap his arms around his fiance from behind, nuzzling his face into her warm neck, getting rewarded by a squeal of surprise in the process.

Kate freed herself from his embrace and managed to spin in her chair to find out who had just assaulted her, though she knew pretty much right away from the feel and the scent and just intuition alone who the man wrapping himself around her would be.

"Everything okay?" she asked with amusement, looking him up and down, checking him over for injuries, bumps to the head, anything that might explain his sudden appearance and even more surprising behavior.

Castle nodded vigorously, his face a serene mask he was attempting to use to conceal the surfeit of emotion swirling beneath the surface.

A mask that kept slipping.

"Can we—?" he asked, gesturing towards the break room.

"Sure. Hey, Ryan. Answer my phone if it rings, would you?" Kate called out to the Irish Detective.

Then she took hold of Castle's jacket and towed him off towards the mercifully empty break room by the cuff.

Castle headed straight for one of the high top tables in the center of the room and took a seat.

"Do you want coffee?" asked Kate, her forehead knit into a frown of puzzlement at his sudden seesawing behavior.

"No. No, coffee. I just—"

Kate slid onto the stool opposite him, and then she reached across the table to cover his hand with her own. "Hey, what is it, Castle? You look…you look as if you've seen a ghost," she said, reaching out to stroke his chin with her fingers.

"What font is that?"

The writer suddenly pulled the letter out of his pocket and laid it flat on he table between them, smoothing it down reverently with his fingers, over and over, to eradicate the creases.

Kate stared at the letter, at this shaky version of her own cursive, at the blood smear in the top left hand corner, and a shiver passed through her as she remembered with pinpoint clarity the moment of the letter's conception – the panic, the fear, the feelings of loss and dread she fought to control. She remembered the sensation of time running out and yet wanting, needing desperately to do so much more before she died. She remembered longing for him, the man she's so in love with she can't bear to think of a life without him by her side anymore.

Kate breathed slowly, touched the corner of the letter with her fingertip, allowing herself to absorb the fact that they were both here now, sitting in front of this memento of that terrible time, still together and very much alive.

She let the fog of panic clear and then she looked up at Castle, at his open, questioning face. "That's not a font. It's my handwriting."

"Exactly," he said quietly, tapping the letter with his fingers. "So, let's forget about Apple Chancery or…or Gaudi Old Style or Lucida Calligraphy. I think we just found the font for our Save The Date cards."

"I—I don't understand," stammered Kate, wondering what on earth he thought of the highly emotional content of the letter, never mind her appalling handwriting.

"This! Your handwriting. Well, yours and mine."

"Castle, I—I'm sorry I'm being kind of slow here, but, babe, you're gonna have to give me more than that to go on. It's been a long, boring morning of form filling and—"

The writer was out of his seat and round by her side before she could finish her sentence. The stool he was sitting on tipped over backwards, crashing to the floor with a loud bang.

But his hands were cradling her face and his lips were on hers, stealing her gasp of surprise and flooding her with everything. She no longer needed to ask what he thought of the letter, because it was all right there in the depth and passion of his kiss and the gentle way his thumbs caressed her face; as if she was the most precious thing in the world.

They only broke apart when Ryan skidded through the break room door on the over-polished vinyl tile to enquire if everyone was okay.

Kate nodded wordlessly to her colleague and he thankfully withdrew, eyes wide, face a little red at the passionate moment he had just had the misfortune to witness.

"Help me out, Castle?" grinned Kate, covering his hand with her own and then nudging for him to sit down again. "What's got you so…excited?"

He righted the fallen stool and then resumed his place opposite her, a glint of that excitement making its way into his eyes.

"I know this amazing typographer, Kate. I don't know why I didn't think of it before. He's a design genius, can make a font for any product, any brand, any…any occasion. I'm going to ask him to design us a font of our own, one that combines both our handwriting…yours and mine."

"You know a guy? Is that what you're trying to tell me?" croaked Kate, laughing as a swell of emotion clogged her throat at his perfect, sweet, romantic and ultimately, just 'so Castle' idea.

Castle nodded, smiling back at her with tears welling in his eyes to match her own. "It's perfect, Kate. You're perfect. And I love you too, with all of my heart," he said, glancing down at the letter that lay between them, his fingers resting on top of the smooth page. "Always."

"Look, I'm pretty much done for the day," said Kate, covering his hand with both of hers. She squeezed it to reassure him that she was here, alive, unbelievably grateful that they hadn't had to use the letter for the purpose she had originally intended.

"So how about we get out of here and I take you somewhere really nice for lunch? We can get a good bottle of wine and then I can tell you all the things I didn't have time to put down in that letter?" she suggested, looking at him with such joy and eagerness that it took his breath away.

Castle grinned at her, disbelieving, a man so much in love. "Sounds…amazing."

"Oh, it will be," Kate assured him, lightly sweeping her thumb over the back of his hand. "And then afterwards, we can go home and maybe put in a little hard work on our…font," she added, with a wink. "What do you say?"

"Where do I sign up?" blurted Castle, hopping down off his stool, realizing for the first time when he caught sigh of his feet that he had left home in such a hurry he was still wearing his slippers.

Exactly one month later, Katherine Houghton Beckett and Richard Alexander Castle's Save The Date cards were sent out in the mail to close friends and family, the unique font a fabulous blend of his and her handwriting that they both have saved on their computers to use from this day forth.

Castle is currently working on the design for a family crest.

The End.

Love to hear your thoughts, if you have time. Thank you for reading. Liv