A/N: So, Vaughn, huh? What about that bad boy. Let's see what happens next, shall we?

Chapter 10 – Potholes On The Road To Paradise

Previously...

"Kate, will you marry me?" asks Castle impulsively, just as the elevator doors open, and in walks Eric Vaughn.

Castle freezes. But Kate is too stunned by his question to notice; the simple words of his proposal still echoing around inside her head like a mantra. When her brain does begin to function again, she sees that, instead of looking expectant, hopeful, joyous, or even nervous, like the man in love he seemed to be just a second ago, Castle looks stricken, shocked, maybe even a little angry, and he's looking past her, instead of at her, to boot.

She's on the point of asking him what's wrong and turning round to check where his gaze seems to be fixated, when she hears the cool, clipped tones of a familiar English accent, a cultured voice that instantly sends a shiver down her spine.

"Good evening, Detective. We meet again."

Kate looks up at Castle and he nods at her imperceptibly confirming her fears, his eyes dead, mouth drawn into a firm line, robbed of his moment of triumph - victory so close – by the man who has become his most recent nemesis.

Kate slowly pivots on her heels, turning to face the man who almost ruined the best relationship she's ever had.

"Kate," smiles Vaughn, warmly, his voice coated in honey that drips over the syllables of her name, as he holds out his hand to her. "So good to see you again. And don't you look ravishing."

And in that split second, it's as if she's seeing this man afresh, seeing him for who he really is for the very first time. And she's surprised to find that she doesn't like what she sees at all.

Kate shakes her head slightly, standing her ground, her right hand hanging limply by her side as she refuses Vaughn's handshake, the left one clutched tightly around her Champagne flute, her knuckles turned white.

"And Mr. Castle," sings Vaughn, looking past Kate at the writer, seemingly not put off in the slightest by her rebuff. "What a surprise to see you here."

"I…" stammers Kate, turning back to look at Castle, the ruins of his proposal lying in shattered, invisible fragments at their feet.

Just when it seems that things can't get any worse, Captain Gates appears along the corridor and she's headed right in their direction.

Kate makes a split-second decision, seizing the opportunity to head her off at the pass. She touches Castle's arm, speaking to him in barely more than a whisper.

"Be right back," she promises, communicating as much with her eyes, as by anything she says.

She doesn't hang around to see how he responds.

"Kate," beams Gates', peering past her to where Castle is now in something of a Mexican standoff with Eric Vaughn. "Having a good time, I hope?"

"Sir, can I have a word?" she asks, taking her boss by the arm and leading her back around the corner out of earshot.

"Is there a problem, detective?" asks Gates, unamused by Kate's tone and the firm grip her subordinate has on her elbow.

"Why didn't you warn me that Eric Vaughn was going to be here?" asks Kate, plaintively, her head reeling with all that's just transpired.

Richard Castle has just proposed to her. Actually proposed. And now she can't tell if the only reason he did so is because Eric Vaughn showed up on the scene.

"Kate, I did try. On two occasions," Gates assures her.

"Sir?" asks Kate, shaking her head in confusion, wondering how on earth she could have missed that.

"When we met downtown, and my dear, sweet, clueless husband invited you two along tonight. If you remember, I did try to dissuade you from coming…" she explains, pursing her lips and raising an eyebrow, waiting for the penny to drop.

"Oh," nods Kate, remembering the look of discouragement on her boss's face when the invitation was made and then hearing her say something about them having better things to do on their weekend off than spend it with a bunch of cops. "And the second time?" she asks.

"I fully intended to warn you as soon as you got here tonight. But then I got side-tracked when the Kellys arrived. I'm sorry. I know things got a little…difficult for you and Mr. Castle when you were assigned to protect Vaughn. But this is something you will both have to learn to navigate if you want to continue working together," advises Gates, with more sympathy and understanding that Kate honestly expects. "You know, Department rules are these for a reason, Kate. Not just to spoil your fun. This is one of those reasons," she points out, patting Kate on the arm.

"Thank you, Sir," says Kate, nodding thoughtfully. "And thank you for entertaining us tonight. But I think maybe it's time we went home," she says, quietly.

"You're very welcome. Both of you," she says politely, turning to walk away. But then she backs up a few steps to add, "You should know that everyone has been saying what a fabulous couple you two make. And, Kate, I might not acknowledge it most of the time, but I have witnessed first hand how devoted that man is to you, how hard he works for you and your team. Don't let momentary distractions sway you from your path. Enjoy the rest of your weekend. I'll see you back at the precinct on Monday."

When Kate turns around, both Vaughn and Castle are nowhere to be seen. She feels sick to her stomach. This should be one of the most special moments of her life, of both their lives. In her one-and-done view of the world, a woman should hear only one proposal in her lifetime, and hers has just been ruined; thrown into question by the untimely reappearance of Eric Vaughn. They've spent the last couple of days tearing each other to shreds over this. No way is she going to let the progress they've made go to waste.

She sets out looking for Castle, intending to get them both the hell out of there so she can talk to him in private. She heads for the kitchen, believing that might be where he'd go, seeking solace in food perhaps.

But when she enters the kitchen, she is confronted by a perfectly coiffured Eric Vaughn instead, his slim frame clad in custom made suit, shirt and shoes, lingering over by the canapés, deep in conversation with his personal assistant.

"Sonia, could you please give us a moment," she hears him telling the slinky young woman the second his eyes alight on Kate.

The assistant tosses Kate a haughty, starved-looking stare and then gavottes past her out of the room on the highest pair of Louboutins she has ever seen, curls bouncing perkily against her bony back.

"I hoped I'd see you again," says Vaughn, with trademark directness, just as Kate turns away to follow the assistant out of the room when she realizes that Castle is obviously somewhere else in the apartment. "In fact, I tried hard to make certain that I would."

"Excuse me?" she replies, turning back to face Vaughn, not believing what she's hearing.

"Oh, don't be naïve, Kate. How do you think I got to where I am today? By holding back when I saw something I wanted? No," he says chillingly. "If I see something I want, I go after it, just like the majority of the people in the next room."

"Are you saying what I think you're saying?" asks Kate, wondering how on earth this man and his pushy candor ever held any sway over her.

"I'm saying you're the sole reason I came here tonight. I thought there was a good chance that your boss and her successful husband might include you on the guest list. You are elegant, poised, articulate, an asset in any social setting, and Victoria's high-flying, most successful protégé. And I was right," he adds, sounding almost as if he's gloating. "Here you are," he purrs, appraising her like a piece of fine art.

"I'm here with Castle. We were invited as a couple," explains Kate, keen to disabuse Vaughn of any ambiguity he might have sensed from her over her relationship. "And whatever impression you might have gotten from me, whatever you think you might know about our relationship, you're wrong. Now, I accept that that was partly my fault. I wasn't clear enough at the Fairmont. But I'm telling you now, so that there can be no misunderstanding. I'm with Castle."

"No. No, Kate, we made a connection in that hotel suite, you and I. This is destiny," insists Vaughn, still failing to take no for an answer.

Kate snorts derisively, but he surprises her, catching hold of her arm when she makes a move to leave the room.

"I don't believe in destiny," she tells him, coldly. "Now let go of me," she insists, slowly lifting her arm, hoping he will simply release her without any more trouble.

"Kismet, then. Fate," he attempts, not giving up, gripping her more tightly, until her bracelet digs painfully into the bones of her wrist. "Whatever name you want to give it, Kate, this meeting was meant to be."

"I don't believe in fate either," says Kate, through gritted teeth, trying hard to remain calm, since she is in her boss's home, there's a room full of influential people right next door and she does not want to make a scene. She draws herself up to her full height, and rounds on Eric Vaughn, her voice low and threatening as she kills this dead once and for all. "But I'll tell you what I do believe in. I believe in Richard Castle. And he's twice the man you'll ever be. So, once again, let me go. Before I knock you on your ass."

She's just wrenching her wrist free from Vaughn's grip when Castle appears at the entrance to the kitchen. He sees them standing close together and freezes, his face turning to stone. Then he turns on his heel and flees.

"Stay away from us," hisses Kate, as a parting shot, jabbing a finger in Vaughn's direction, immediately leaving to go after Castle.

She catches up with him out by the elevator. He's pacing the floor when she first sees him, then he pauses, tapping his foot impatiently in front of the elevator doors, muttering 'Come on, come on,' to himself, as she watches from a slight distance away. He has his hands jammed into his pockets, and his posture is stooped. Kate's heart twists like a tourniquet in her chest watching him torture himself over what she suspects he thinks he just witnessed.

The pianist in the lounge begins a rendition of Billy Joel's 'Piano Man', and a few tuneless voices join in to sing along with the rousing, melodic number, the party atmosphere suddenly kicking up a notch. Kate's heart clenches when she hears the song, memories of Roy and the boys and a bottle of ancient Whisky Castle paid far too much for coming back to flood her mind. How close they all were that night, how happy. The song taunts them both, though neither says anything, and suddenly she can't wait to leave the party either.

"Let's get out of here," says Kate, sweeping into the elevator ahead of him when the doors open just as she arrives by his side.

Castle stands on the outside, frozen, as if he can't bear to be in her company.

"Castle," she says, putting a hand out prevent the doors from closing on him, the elevator operator evidently having left for the night. "Let's go."

He's still hesitating when another couple of people appear from the party and he's forced to get in alongside her lest things look really awkward.

They make polite small talk all the way to the ground floor, while Castle stares at his feet, failing to join in.

"Do we have to call Sam?" asks Kate, looking up and down the street for Castle's car service.

"I already did," he says grimly, pointing to the black Mercedes idling on the other side of the street.

"Great. Then let's go home," says Kate quietly, heading for the car.

"Not until you tell me what that was back there. You and Vaughn in the kitchen having a cozy little chat," he says, sounding spiteful amidst his hurt.

"You may think that's what you saw, but believe me you didn't," Kate tries to reassure him, not wanting to get into an argument over this out on the sidewalk.

"Then tell me, what was that?" he insists.

"Rick, don't do this," sighs Kate. "Don't…ruin a perfect evening over nothing."

"Ruin—?" gasps Castle, as if she just slapped him. "I just proposed to you, Kate. And before I can even get an answer, I find you alone with that guy having some kind of intimate conversation. What am I supposed to think?"

"Is that why you proposed?" asks Kate, voicing the one question that's been praying on her mind since Vaughn showed up at the party; materializing like a specter come back to haunt them.

"Seriously?" asks Castle, his face like thunder.

"It's a valid question," insists Kate, standing her ground. "One minute we're talking about moving in together and then this guy shows up and all of a sudden marriage is on the table? Seems like suspicious timing to me."

"I asked if you wanted to have a baby with me tonight," points out Castle, his voice frighteningly controlled all of a sudden. "And you doubt whether marriage was on my mind?"

"Let's just go home. I'm tired. I don't want to do this here."

Castle catches Kate's arm to prevent her stepping off the curb when a car suddenly approaches from the left, and she winces, pulling away from him to cradle her wrist.

"What the hell is that?" asks Castle, gently reclaiming her arm to examine her wrist, which now has a purple mark around it where her bracelet was forced into her skin by Vaughn's grip.

"Nothing," she tells him, pulling away and hurrying across the street to get into the back of the car.

"Kate, that is not nothing. Did he do that to you? Did Vaughn hurt you?" Castle demands.

"I said it's nothing, Castle. I handled it. Okay? Now let's just go home."

They begin the car ride in stony silence. Kate is heartbroken by how tonight has turned out, as much for Castle as for herself, but she can't seem to find the words to tell him that. The one question she's fixated on is whether Castle saw Vaughn and only decided to propose to her as a result. She can't get it out of her head, that the proposal was a knee-jerk reaction to seeing the entrepreneur again; just some way to lay claim to her in front of the guy. But if that's what it was, his planned failed spectacularly.

The car glides along the edge of Central Park, past Grand Army Plaza, some of the best, most romantic sights New York City by night has to offer passing them by. But both remain oblivious to its beauty, too deep in mourning for the wonderful finale tonight's party could have held for them.

All too soon, the car is turning off Fifth Avenue onto East 8th Street, bringing them to the junction with Broadway. Kate stares out of one window and Castle out of the other, a cold, silent space opened up between then again. Her wrist aches in her lap, a painful reminder of how she got things so wrong when she fell for Eric Vaughn's charm the first time she met him. Five more minutes and they're turning left on Spring, right onto Lafayette, before covering the final few blocks to the corner of Crosby and Broome.

The driver bids them goodnight and thanks Castle for the tip he presses into his palm when he holds the door open for Kate.

She feels like weeping, but is too emotionally exhausted, devastated that things have turned into such an unholy mess, none of it of their making, if she's honest, save for a failure to communicate.

Another silent, sullen elevator ride up to the loft, and a weary fish around in her clutch for the single set of keys they have with them, follows.

Martha is sitting alone watching television, a glass of red wine in one hand, and she raises a welcoming, smiling face to them as soon as they come in.

"Well?" she asks, cheerfully. "Did you knock 'em all dead?"

"Not now, mother," snaps Castle, marching straight past her towards the bedroom.

Kate shakes her head silently at Martha when she begins to ask, "What did I do?" advising her just to let him go.

She's about to sit down beside Castle's mother when he reappears, his jacket off, but other than that still dressed as before.

"Can I talk to you for a second?" he asks Kate, his face fractionally more open, though he still looks unhappy or serious or something Kate can't quite put her finger on. Maybe determined is a good way to describe him. But she's not sure she could read him if she tried right now.

"Uh…sure," she says, following him into the bedroom with a frown.

She casts a concerned glance at Martha as she goes, raising her hand in a half-wave when the older woman offers her a smile of encouragement.

Castle is standing on his side of the bed waiting for her, hands clenched by his sides. His back is turned to her, so she can't see his expression when she enters the bedroom.

"Close the door," he tells her, tersely, rubbing a hand down over his face, one leg jiggling ceaselessly.

"Look, I don't know what you think you saw tonight, Castle, but…"

"It's fine, Kate. You don't have to explain," he cuts in, shaking his head, almost as if he's afraid to hear what she has to say.

"But, I want to. And I think you need to hear this. Castle, I went into that kitchen looking for you, not Vaughn. He just happened to be there when I…"

"I said none of that matters anymore," interjects Castle, the tone of his voice alerting her to a finality in what he's just said. "As long as he didn't hurt you," he adds, finally turning round to look at her.

"No," Kate reassures him, shaking her head. "No, he...he didn't. But, I did get a chance to set the record straight. To tell him what I should have told him in the first place. That I'm with you and it's serious. We're a couple. And I'm sorry if I ever made you doubt that."

Kate takes a few steps towards him, but is halted midway across the floor when Castle holds up a hand to stop her getting any closer.

"Please. I just…I need to say something now. If you'll just listen."

"Uh...yeah. Sure," she replies, hesitantly, wrapping her arms around her own body, terrified of what she believes to be coming next.

"Kate, you asked if my proposal tonight was in response to Vaughn showing up at that party. And I can understand why you might have thought that. But, you were wrong. Nothing could be further from the truth. And if you need proof," he tells her, suddenly dropping to one knee and holding up the engagement ring, "then here it is."

The room is silent, save for Kate's sudden intake of breath.

"Kate, I love you. I love you with all my heart. I asked you once already and I didn't make a very good job of it, so, I'm going to ask you again. Katherine Beckett, will you marry me?"

The anger is suddenly gone from his face, smoothed away to be replaced by a look of loving tenderness and hopeful expectation she has come to expect from him.

"Castle…" she whispers, a nervous bubble of laughter building in her throat, half choke, half sob.

"Look, I don't care about any of that other stuff. This just feels different to me. How we are with one another. You've stopped running, and I'm not saying that things between us are perfect. We still have work to do. But everything we've talked about today, how close we were tonight after almost tearing each other apart… That tells me that this is right, Kate. That we have something real. And...I just...I want to be with you. I want us to make a future together, and I'm pretty sure we have what it takes to make that happen. Now, if you need time, I understand. Two proposals in one night might be…"

"Yes!" blurts Kate, her hand flying up to cover her mouth, shielding her tearful smile from him and capturing a sob, the other hand pressed over her racing heart.

"Was…was that your answer or are you just agreeing with me?" asks Castle, his eyes wide, breath held in anticipation.

Kate nods vigorously.

"No. I mean, yes. Yes, is my answer. And yes, I agree with you too. To hell with everything else. I love you, Castle. This is it for me."

Castle immediately gets to his feet, hurrying towards her. They meet in the middle of the room, and Kate holds out her arms to him, and they fall into a dizzying embrace, holding onto one another as tightly as they dare.

"Oh, I love you," he whispers, soothing her, rocking her, kissing her damp cheeks, her eyes, her smile, her hair. "I love you so much."

"We're getting married," whispers Kate in disbelief, her forehead resting against his, her breathing shallow, her heart hammering, hands reaching up to cup his face. "We're getting married."

"Sounds crazy, doesn't it?" acknowledges Castle, stroking his hand up and down her back. "So, how about you let me put that ring on your finger and we make it official?"

Kate eases back enough to hold out her left hand, fresh tears welling in her eyes to blur her vision.

"Your hands are shaking," remarks Castle, as he slides the diamond-encrusted, platinum band onto her finger.

"It's so beautiful," breathes Kate, staring at the ring in amazement – an unusual oval cut diamond, bordered by two smaller diamonds on either shoulder, the band itself encrusted with pave gemstones that dazzle in the lamplight.

"And you had this? The whole time we were fighting, you already had this?" she asks, looking up at him to search his face.

Castle nods, admiring the engagement ring now that it's actually on her finger, instead of sitting lifeless in a box at the back of a drawer, as she twists her hand back and forth letting the diamonds catch the light just as he did, all by himself, not four hours ago.

"I needed to be sure," he admits quietly, kissing her temple.

"Of me?"

"No. I needed to be sure of me. That I could count on myself to work through the things that were holding me back from committing to you and not just…shut down again. You know me, Kate. And yet you're still here."

"And you know me," she insists, squeezing his hand. "So...trust issues?" she suggests.

"Trust. My own past failures. Jealousy. Wondering if I deserved you, if this was what you wanted. Was I good enough, smart enough. All of that."

"And you picked Gates' party to reach your epiphany?" she smiles, giving him a tender, indulgent look.

"I didn't want to wait anymore. Tonight...it just...it felt right."

"You never were one to do things small, were you?" laughs Kate, kissing him again and running a hand through his hair, cradling him to her.

"Nope. Go big or go home about sums me up. And now that we are home…" he grins, gently smoothing the hair away from her face, caressing her cheek with his thumb. "Come to bed with me?"

Kate kisses him, her body set on fire the second their lips meet, chasing after one another, tongues probing, teasing, both breathing heavily, her head spinning with a surge of desire for the man she's just agreed to marry.

When they part, it's on a groan of displeasure from Castle, his fingers clutching her body tightly to keep her close to him. Kate drops her head onto his chest and leans into him, wrapping her arms around his waist.

"Your mom. Castle, she's out there by herself wondering what the heck is going on. You should go talk to her. Let her know that everything is okay between us at least."

"You sure you're ready for this? For all the fuss and the hoopla that's coming? Because those two are going to want in on this wedding, I'm warning you."

"Are you?" she grins, eyes dancing with excitement.

"With you by my side? I think I'm ready for anything."

"Now that's just sappy," laughs Kate, slapping his chest.

"You don't like sappy, detective? You want manly instead? Because I can do manly, Kate Beckett," he growls, picking her up and dumping her on the bed in a giggling heap, before draping himself on top of her.

"Your mom," reminds Kate, a couple of minutes later, before they get beyond the point of no return; his hand already under her dress, his pants unzipped.

"Ugh," groans Castle, thumping the mattress. "You're too considerate," he whines.

"Gotta keep my mother-in-law sweet. You'll thank me in the long run," she promises, patting his cheek and rolling out from under him.

"Breakfast in bed tomorrow?" he cajoles, dragging her back into his lap for a cuddle, pressing a kiss to her bare back.

"If you're cooking?"

"When am I not cooking?"

"Are you complaining about your wife already," murmurs Kate, leaning in to brush her smiling lips over his, stroking inside his mouth with her tongue, fingers gently toying with his ear and the soft hair at the back of neck.

"Never," mumbles Castle, his eyes drifting closed at her soothing touch, as they tumble backwards on to the bed again, grinning. "Never."

A/N: Okay guys, we've reached the end of the road on this one. Thank you for travelling with me on this Caskett journey of self-discovery. Until we meet again. Thank you so much for all the funny, threatening, cajoling, heartfelt reviews. You're amazing and you make it all worthwhile. Liv