Happy Castle Fanfic Monday! This story was inspired by a recent twitter conversation between Lou/InkyCoffee and Lindsey/ipreferwestside. The end result may not bear a whole lot of resemblance to the ideas they were tossing around, but I still give them the blame, oops I mean credit. :)

Big thanks as always to Meg for beta-reading! *heart-eyes emoji*

Imagine if you will that the events of The Squab And The Quail (5x21) took place earlier in the season, shortly after Significant Others (5x10)...

"Well, if he kissed you, why wouldn't you just push him away?"

Beckett bites back a growl of frustration and settles for giving Castle her patented you're being stupid look. Why does her boyfriend have to be so obtuse sometimes?

He wilts immediately under her glare. "Oh," he mutters, looking away, embarrassed. "Which is ... why he's not dead."

She presses her lips together tightly, wishing they were anywhere else, wishing they weren't here in this ostentatious hotel suite, surrounded by cops and still trying to keep their relationship a secret. Castle's expression is making her anxious - a curious mixture of guilt, anger, and something else she can't quite identify lurking in the blue depths of his eyes - and that in turn only serves to feed her annoyance with him.

"Yo," says Esposito from the doorway. "Our man Barber was at the hotel across the street under an assumed name. He made some phone calls from the room. We're tracing them now."

"Okay, thanks," Beckett says. In a split second, she makes a decision. Her irritation at Castle is about to reach its boiling point, and she can't let it explode in front of all these people. "Castle," she barks, and grabs him by the shoulder, shoving him toward the suite's enormous bathroom.

Ryan and Esposito are huddled around Ryan's phone, and the CSU techs carefully pretend not to be watching as Beckett hustles Castle through the bathroom door and closes it behind them.

As soon as the latch clicks, she whirls to face him, recriminations on her lips - but he ignores her anger and wraps her up in his arms, pulling her so tightly against him that she gives out an involuntary squeak of surprise.

"All I heard was sniper," he whispers into her hair. His hands are trembling on her back, and she hears his heartbeat thumping frantically against her ear. "A sniper shooting at you, and I wasn't here."

"Oh, Rick," she sighs. All of the anger drains out of her in an instant and she slumps against him, her posture softening, sinking into his embrace. "Babe, I'm fine. I'm okay."

He brings one hand around, slipping it up under her turtleneck, his fingers finding the little knot of scarred flesh between her breasts. Holding her against him with the other arm, he touches the scar, seeking reassurance.

He still has nightmares sometimes. He thrashes in bed and cries her name into the darkness, wakes wild-eyed with the sensation of her blood gushing out over his hands. She's had to talk him down quite a few times these past few months, since they got together. So many nights she's had to take his hand and guide it to her scar, grounding him.

She aches for all the nightmares he must have had, before, when she was still hiding behind her walls - all the times he probably awoke in the dark, alone, with no one to hold him and remind him that she was alive. Her own nightmares are mostly distant memories now, soothed by the passage of time and the care of Dr. Burke; she hasn't had a panic attack in months; but Castle still suffers, and not infrequently. And he tries so hard not to smother her with his lingering anxieties. Her sweet, strong, stupid man.

"Castle," she murmurs, gently pulling his hand out from under her shirt. He lifts it to her face, dusting his fingertips along the curve of her cheek, cupping her jaw in his wide palm.

"I'm sorry I've been such a jerk about this whole situation," he mutters, not meeting her eyes. "You're just doing your job, and I'm acting like a jealous caveman."

"It's okay," she answers, feeling some previously unnoticed tension seep out of her shoulders at his words. "It really is. And I'm ... I'm sorry too."

"For what?" he asks, lifting his eyes to hers at last. She winces and takes a deep, careful breath.

"Vaughn asked me about you, about us. He asked if it's serious. And I-" Her throat is suddenly tight with guilt. "I said yes, but I hesitated first. I guess that's why he thought he could try to kiss me."

Castle's fingers tighten reflexively on her skull. He pushes his hand into her hair and brings her mouth up to meet his. The kiss is hard, searing, but brief. It's not a kiss that attempts to lay claim or make demands. It's just an overflowing of emotion that he can't hold back, and she welcomes it. The press of his lips feels so right, erasing the lingering wrongness of Eric Vaughn's attempt.

Somewhere deep down, her gut is clenching with trepidation at the knowledge that no other man's touch, no other man's kiss, will ever feel right again.

Castle releases her, self-consciously dropping his hands to his sides. "But ... you said yes?" he asks hesitantly. "It is serious?"

Her voice is shaky and she curses herself for cowardice when she says, "Isn't it?"

Something sparkles in his eyes and she sees him thinking about making a joke, but he stops himself and says quietly, "It is to me, Kate."

God, she loves him so much. It comes swelling up her throat and nearly chokes her, but she manages to get out, "Me too."

Relief washes across his face and he leans forward to kiss her again, softly.

"We should…" he murmurs, and she nods reluctantly.

"Yeah." They really need to get back out there, get back on the case. The rumor mill is probably already churning furiously.

But she needs to get one thing cleared up first. "Castle ... about Vaughn-"

"No, don't." He puts up a hand to stop her. "Kate, last week I invited my ex-wife to stay with us, which was…" he shakes his head ruefully, "incredibly stupid of me. But you put up with it, and the least I can do is return the favor."

"It's not the same," she murmurs, and he shrugs agreement.

"No, but it's in the same ballpark. You put your trust in me, so I need to do the same for you."

"I love you," she sighs, dropping her forehead onto his chest for a brief moment.

"I love you too." He squeezes her shoulders, and then she steps away and opens the door.

They emerge from the bathroom to find that Esposito has identified whom their shooter was calling. But it's late by now, so they'll have to bring her in tomorrow.

Beckett reluctantly takes out her phone and calls Captain Gates.

"Sir, I'm ready to resume protection duty on Mr. Vaughn," she says, keeping her voice steady, although her jaw is clenched tight. Castle stands beside her, not talking, not touching, but reassuring her with his solid presence at her shoulder.

"That won't be necessary, Detective," her boss says tiredly. "We've moved Mr. Vaughn to a state-run safe house for the night, staffed with troopers around the clock. You should go home, get some sleep. We need to solve this thing tomorrow."

"Yes, sir." Beckett hangs up and breathes out a loud sigh of relief. Castle raises his eyebrows questioningly.

"Beckett?"

"Take me home, Castle."

And so they go back to her apartment. They don't talk about anything of consequence. They get into bed and hold each other, and kiss softly, but she's exhausted, so that's as far as it goes. She falls asleep secure in Castle's arms.

They both sleep heavily throughout the night, no nightmares disturbing their rest.

The next day they solve the case and, with a great sense of relief, Beckett bids Eric Vaughn goodbye. She doesn't feel the slightest bit tempted by the soulful looks he keeps giving her throughout their final conversation. There was never any question about the choice she would make.

That evening, Castle calls her into his study to watch him cut the cord on his XBox controller.

"You were right," he says. "I've been taking you for granted, but no longer."

Her jaw drops when she sees all the preparations he has made in the bedroom - massage oil, candles, rose petals, champagne. The man certainly does know how to put together a grand romantic gesture.

He sweeps her into a kiss, but when their lips part, she murmurs, "Castle?"

"Yeah?"

Apprehension gathers in a tight, sick knot in her stomach, but she needs to know.

"Where are we going?"

He studies her for a moment, a small smile lurking in the corners of his mouth and the crinkling of his eyes.

"I don't know," he answers at last, "but wherever it is, you're the only one I want to go with."

The lump in her gut eases somewhat, but she's still not sure. Is it enough?

"Come on," he adds, "you're gonna love this." He takes her hand and leads her toward the bed.

She lets him do it. It's enough ... for now.

A few weeks later, after a disastrous farce with Captain Gates and a pair of earrings, Beckett gives Castle a drawer in her bedroom bureau. She's delighted by the way his whole face lights up when he realizes what it means. She feels light-headed, giddy with how much she loves this man.

He puts his clothes in the drawer and they make love into the wee hours of the morning, caressing and giggling and moaning, whispering I love you again and again as their bodies slide against each other. Then, at last, they sleep.

The next morning, while Castle is showering, Beckett strips the sheets off the bed. As she passes by the bureau, she notices that Castle's drawer is partly open, his pants hanging halfway out, crumpled into a haphazard ball - evidence of the urgency with which he undressed.

She opens the drawer farther to take out the pants - he doesn't have a change of clothes here yet, so he'll need to wear them again - and as she shakes them out, something falls from the pocket and bounces on the floor.

She puts the pants down and leans over to pick it up.

It's a jewelry box. Small, black, square. A lot like the one that accidentally made its way into Gates's pocket yesterday, but some tingling premonition on the back of Beckett's neck tells her that this box doesn't contain earrings.

Her whole body goes still, her muscles and bones suddenly like liquid as she stares at the tiny object in her hand.

"I don't have a comb so I borrowed your-"

Castle stops dead in the doorway, naked except for a towel around his waist. His eyes are as wide as the ocean, fixed on her hand.

"Kate," he manages, and she pulls her gaze up to his face.

"Castle, what..." Her mouth is dry. "What is this?"

"Well, it's a, um." He steps forward, gently takes the box from her fingers. "I think you know what it is."

Her heart is pounding, her breathing fast and choppy. "When?" she gets out. "When, um, how long have you been carrying this around?"

"Since the Eric Vaughn case," he admits, and she feels her eyes go even wider at that.

"The - Castle, that was a month ago."

"I know," he nods, his cheeks turning slightly pink. "I just wanted to, to find the perfect moment. I wanted it to be just right."

She's gazing at him, utterly speechless, so he babbles on. "You know, during the Vaughn case, I realized that I was in danger of forgetting how lucky I am to have you. And if I wasn't careful, I might lose you because I wasn't paying enough attention. And I knew I couldn't let that happen."

"Castle," she breathes. Her eyes are suddenly wet, her voice as unsteady as her knees. "I don't ever want to lose you either."

His eyes flare with pleasure, and he gives that beautiful smile, the one she can never get enough of. "I was going to do this last night," he goes on, "but then you - with the drawer - and I - that was incredible, Kate." He sighs wistfully. "You never cease to amaze me."

"The feeling is mutual, babe," she answers softly, swallowing hard, her throat tight.

"So..." He guides her to the bed and gently nudges her to sit. "This isn't exactly how I had in mind to do this. I don't even have my tuxedo."

"Overkill, Castle," she chuckles, even as her tears start to spill over.

"Right, I know. I know." He gazes down at her, so much tenderness in his eyes that she can almost feel it flooding into her, filling up all the cracked and broken spaces in her heart.

"I just don't ever want you to think that there's any chance of me taking you for granted. Or forgetting how extraordinary you are. I don't ever want you to doubt how much you mean to me."

The words strike into her like lightning, sending shivers up her spine. Of course he knows exactly the right words to give her. It's everything she has needed to hear from him, to put all of her fears to rest.

Then he drops to one knee and she's already crying before he even gets the little box open. The whole room, Castle's beloved face, and the diamond ring glittering in its velvet bed, all swim blurrily before her eyes.

"Katherine Houghton Beckett, will you marry me?"

"Yes," she gasps almost before he finishes the sentence, "yes, god yes." She's crying and laughing at the same time, as he slips the ring onto her finger and surges up to kiss her. His momentum knocks her over backward and they land on the bed, his bare chest pressing her down as their tongues slide together.

"I love you," he murmurs, breaking the kiss at last, lifting her hand to admire the ring. "So much, Kate."

"I love you too," she whispers back, squeezing his fingers. She feels her lips curve devilishly as she adds, "Eric Vaughn never had a chance."

Castle pauses, narrowing his eyes at her. "Promise me you'll never again mention his name in our marital bed."

"It's a deal," she grins, her heart fluttering at the word marital. Oh god, they're getting married. She's going to marry Richard Castle. Oh god.

He relaxes, smiling down at her. "Don't be nervous. We're gonna be great."

"I know," she replies, an unaccustomed feeling of confidence suddenly flooding through her. Nerves or no, he's right: they really are going to be great. She's sure of it at last.

She smiles back up at him. "Now are you gonna kiss me, or what?"

"Always," and he does.