A/N: I always wanted to write an epilogue for this story, but it took a while for inspiration to strike and to find an ending I was happy with—hope you like it!

9 Months Later

"Yes, Gina, I know it's my launch party," Castle says into his phone with slight exasperation.

"Are you on your way, at least?" she asks in a shrill panic.

Kate slips the phone from his hand and puts the cell to her ear.

"We're just around the corner, Gina," she says. Nodding her head, she hums as his editor yells about punctuality and the mayor. "I'll make sure he comes in time for the speech. I'm not letting him out of my sight, I promise you." Her fingers grasp his tightly. This time he was going to arrive.

He peeks out the window at the police escort guiding their path towards the venue. It was just Ryan and Esposito, but Kate insisted on the added protection.

When Alexis had seen the flashing siren on the undercover unit, she'd begged to ride with Uncle Javi and Kevin. Martha had laughed, joking that the girl was taking after her father before volunteering to ride with the four-year-old and stepping into the squad car.

Kate snaps the phone closed and tucks it into his coat pocket. "All set," she sighs. She pats her free hand on his chest and lays her head on his shoulder, closing her eyes briefly.

His heart cracks open at the sight of her so relaxed and content. Happy.

"Stop staring at me, Castle," she says.

He chuckles and smooths his thumb over her left hand, resting it on the ring he'd put there last week. She lifts her head at his touch, a knowing smile on her lips.

One Week Earlier

Kate fumbles with the key to the loft as she tries to open the door. Work went longer than she expected and Castle had left early for a last-minute book meeting. It was a tough case and she missed his silly theories and reassuring smiles.

She finally eases the door open, and she spills into the loft, her bag dropping from her shoulder as she removes her coat.

"Castle, you home?" she calls out as she puts her things in the closet. The place is silent. Beckett's eyebrows pinch together. She checks her watch. His meeting was supposed to be over by now.

"Martha? Lex?"

That's when a small redhead comes barreling down the stairs. "Kate, Kate!"

"Woah, slow down," says Beckett as the little girl crashes into her. "It's good to see you, too," the detective laughs as Alexis throws her arms around her.

Giggling, the redhead pulls away and then tugs at Beckett's hand. "C'mon!" She starts leading the brunette up the stairs.

"Where are you taking me?"

"Daddy has a surprise," Alexis says matter-of-factly.

"A surprise?" Beckett says, amused. She follows the girl into the hallway and stills when she sees the ladder to the roof. It's wreathed in fairy lights and Martha's standing next to it with a smile on her face and tears in her eyes.

"What's going on?" Beckett asks, nerves fluttering in her chest. She looks down at Alexis who covers her mouth with a finger.

"Can't tell," she whispers.

"Martha, are you alright?" Beckett asks, reaching out a consoling arm. The older redhead waves her off.

"I'm sorry, darling," she says with a sniffle, "You how I get emotional. Richard's waiting for you," Martha gestures upstairs as she wipes under her eyes. Alexis pushes at her legs and Beckett chuckles.

"Okay, okay, I'm going!"

She grabs the rungs of the ladder and starts to climb, cool air brushing the top of her head. When she reaches the top, she stops and sucks in a breath. She knew Castle was renovating the roof for the past couple of weeks, but he kept everything a secret. Now it's covered in flourishing greens, swirling rock paths, and blooming flowers—a real garden. In the middle is a circular patio surrounded by vine-draped arbors. And there are candles everywhere, casting the roof in a soft, shimmery glow.

Castle stands in a ring of candles on the patio. He's wearing a well-fitted suit and blue collared shirt that makes his eyes pop.

"Is that your ghost outfit?" she asks, her lips quirking in mirth.

"I didn't have a last minute book meeting," he says.

Her heart is suddenly beating out of her chest.

"Because I wanted this to be big and…"

"Intimate," she finishes, her eyes meeting his.

He offers his hand out to her, and she takes it, his palm enveloping hers. He tugs her to him.

"Hi," he says softly.

"Castle, what is all this?" she asks, already knowing the answer.

"I thought this place could use a little sprucing," he says with a shrug.

She rolls her eyes at him.

"Your mother is practically crying her eyes out downstairs."

"That's the last time I ask her to help in a surprise proposal," he says, huffing in mock disappointment.

"Is that was this is?" she asks, a smile taking over her face. "I don't see a ring."

"You really don't miss a thing, do you?" he says, reaching a hand into his pocket. He pulls out a tiny velvet box and brings it between them.

She can barely breathe. He's really doing this.

"This is where I fell in love with you. I'm wearing this because this was how I fell in love you—a ghost of myself."

She snorts.

"You're such a writer."

"That's why you love me."

"You're an idiot," she says, her eyes welling with emotion.

"You made me feel whole. You inspired me. And you broke me out of a hospital. No one's ever done that for me before. And I've never met anyone like you." He moves to open the box, but she stops him.

"Wait, I want to say something," she says. "When I first saw you, it scared the hell out of me. But you got under my skin and I couldn't stop thinking about you," she says, bringing her other hand to play with his collar, "Because you were the one whose words saved me when I was drowning."

"Kate," he says, palming her cheek and she shakes her head.

"I'm not done," she whispers.

"Right after my mom died, you had a book signing in the city. I waited over an hour in line to see you."

"You've never told me this," he murmurs, rubbing his fingers soothingly on the shell of her ear.

"Because it used to be a painful memory. A reminder of a time when I couldn't think of anything but my mom's death. But you…" she trails off, gazing into his eyes, "You made me laugh. You did that thing where you read right through me and said exactly what I needed to hear."

"You look like you need a drink," he says suddenly, a light sparking in his eye.

Beckett opens her mouth, stunned. "You remember that?"

"I didn't know that was you, but I always remembered the incredibly gorgeous girl with sad eyes from the Union Square signing. I think I wrote a short story about you."

"You did not."

"I did. I wrote that I was going to marry that girl."

"Okay, you definitely didn't write that."

"You're right, but…" he cracks open the velvet box, "But I'm asking her right now." He bends down on one knee, the simple but elegant solitaire diamond glinting in the candlelight. A tear sneaks down her cheek as she takes in the moment and the beautiful man in front of her.

"Will you marry me?" he asks, his blue eyes glistening.

"Yes, yes, I'll marry you."

She reaches up and kisses him, squeezing his finger.

"Are you sure you want to announce the engagement now?" he asks, "We could just release a statement after the book hype quiets down."

"I'm sure," she says and his heart expands.

"And this morning, with the papers? You didn't have to sign those, you know?"

"Castle, stop it," she says, bringing a calming hand to his jaw. "I love Alexis," she presses, "She's my family, too. I just decided to make it official, okay?"

His throat clogs as he takes her in—the beautiful and caring woman who adopted his daughter without hesitation.

"I love you," he whispers.

"I know," she says.

He chokes on a laugh.

"You Han Solo'd me."

The car pulls to a stop in front of a red carpet.

"Come on, Princess, we have a party to attend," she says, smirking.

Their driver opens the door and they step out together into the flashing lights.

"Look, it's Nikki Heat!"

She steps out her heels when he opens the door to the loft.

Martha carries a sleeping Alexis upstairs.

"Now I know why you didn't let me see the final draft," she says, running a hand over the dedication page of Heat Wave.

He rests his chin on her shoulder, his arms booking her waist. "I mean it, you are extraordinary," he says, dropping a kiss behind her ear.

She turns in his arms, winding her own around his neck.

"You didn't have to give me a co-author credit, too. Those were all your words," she says softly.

"But it was our story, and you helped me write it."

Her eyes shine as she looks up at him.

"I wish my mom could see it. She would've loved it. And you."

"Really?"

She nods, too overcome for words.

"Wherever she is, she's proud of you," he says.

She raises up on her toes and kisses him. She pulls away with a look in her eye.

"I, uh, have something for you."

She walks into their bedroom and grabs a bag from the nightstand, handing it to him. She bites her lip with barely concealed excitement.

"What's this?" he asks.

"Just something I bought for Alexis."

"For Alexis?"

He plucks a soft, cotton shirt from the tissue paper, confusion creasing his brow.

"Why are you giving this to me?"

Beckett gently takes the pink shirt from him and shakes it out so he can read the text.

"World's Best Big...Sister," he says.

His mouth falls open as his eyes find hers.

"Does this mean you're—"

"Six weeks. I took a test yesterday, but I wanted to make sure so I went to the doctor's today."

"That's what your secret trip after lunch was!"

She nods, a huge smile splitting across her face.

He looks at her in awe.

"You're pregnant."

She nods again, beaming.

"Does this mean we'll have a shotgun wedding?"

"Or we could wait until the baby is born," she says.

"Whatever you want, but I can't wait to be married to you."

He bends to sweep his hands under her legs and lift her into his arms.

"Castle!" she squeals.

He peppers her with kisses. "Put me down," she giggles.

"As you wish," he says, and falls backward onto the bed, taking her with him. They become a tangle of limbs and breathless laughs.

Later, he lays a hand on her stomach.

"Do you think it'll have ghost powers?"

"Do you really want a baby that can walk through walls and disappear at any moment?"

"So you have thought about it," he says, grinning widely.

She shakes her head with a bemused smile. "I think I've had enough of ghosts for a while."

His mouth turns into a pout. "But if you had never seen mine, then where would we be?"

Her fingers play with the hairs on the nape of his neck.

"I think we would've found each other somehow."

He shifts in the bed to face her.

"Katherine Houghton Beckett, are you telling me you believe in fate?"

"I think I believe we'll always be each other's unfinished business."

He kisses her, his eyes gleaming.

She puts a hand on her belly.

"But if we do have a ghost baby, then we'll have to switch our diaper bags out for proton packs."

His jaw drops open. "Are you saying what I think you're saying?"

"Yeah, Castle."

Her lips curve into that dimpled smile that's just for him.

"I ain't afraid of no ghost."

A/N: Thank you for reading and reviewing. If you recognize the baby reveal scene, I took a cue from Grey's Anatomy—another great ABC show. I can finally mark this story complete! And if you haven't seen "Just Like Heaven," I highly recommend it.