Title: Rock Foundation

Disclaimer: I do not own the Castle characters or their story lines. I just borrow them for fun.

Summary: A Sequel of sorts for my one-shot Rock Solid. Kate and Rick deal with the aftermath of Knockdown and move forward with their lives, learning to balance their partnership with their budding relationship.

Author's note: I'm really excited by the response to this story. I'm enjoying writing it and am interested to see what you guys think of the things that are coming our favorite duo's way. Thank you for reading!

Chapter III:

They sat on a bench in Central Park and watched the world move around them in an odd moment of quiet. A little kid ran past, quickly followed by a young father. He swung the girl up into his arms and she giggled wildly as he spun them around, before the mother walked up with a pretzel and the trio moved away down the path.

"Do you ever think you'd want that again?" Kate asked as they watched the small family go.

"To have more kids?"

"Yeah." Kate took a sip of her coffee and looked out across the park. "To have another child, a family?"

"Sometimes," he replied. "I would only want to do it if I knew the mother would stick around though. I wouldn't trade Alexis for the world, but I want any other children I have to have a truly stable home— to have more than just me all the time."

Kate nodded thoughtfully and played with the rim of her cup.

"Do you think you'd want it? Kids, family, dog?" Rick asked, looking sideways to study her response.

"Oh, someday, yeah. I mean…but…you know, it would be hard with my job."

"Sure, but I bet you could work it out so that the father would spend time with the kids during the day. If not, there's always daycare or a nanny."

"I don't want my kids brought up by a nanny or raised in a daycare," she replied quickly. "They're my kids, you know? Well, they're my hypothetical kids."

"I know. Being Alexis' full-time Dad was something I think I'll always cherish."

"You didn't ever want a nanny?"

"Never. She was too much fun," Rick smiled. "It didn't seem like it would be fair to her either; I could always write when she was asleep, or busy. And then she went to school, and, well, when she was home, I just wanted to spend time with her."

"Mr. Mom," Kate teased gently.

Rick laughed. "And proud of it." They sat quietly for a minute. "I'm sure you could work it out so that you could be home some days, and the father the others."

Kate shook her head. "That only works if the Dad is someone with a flexible job."

"Dating a doctor doesn't really give you a good model for that?"

Kate gave a dark chuckle. "Finding time to see each other, let alone talk or, God forbid, have a real date, is tough. Somehow I don't see us finding time to put a child into that equation. Especially not when he's off in Africa every few months."

"What's he doing there?" Rick asked.

Kate looked over at him and saw only honest curiosity in his eyes. "He's working for the Smile Train. Every couple months, a group of the surgeons at his hospital volunteer and fly out for two weeks."

"I thought he was a heart surgeon? Or is he also a plastic surgeon on the side?"

"He is a heart surgeon, but they send the doctors who are willing to go. He does the more straightforward cases; the really difficult surgeries go to the plastic surgeons. He also does other minor surgery and diagnosis when they set up, since they're probably the only doctors those villages will see for years."

"That's very impressive."

"It is," Kate agreed. "It's a really worthwhile program." She closed her eyes for a minute, feeling selfish for having been upset with him for leaving for a month to do an extra rotation. He was saving the world. That was more important.

"It's got to be tough to have him gone so much," Rick said.

Kate snapped her head to look at him. "Are you in my head now?"

He laughed. "No, you just don't look that happy about him being gone."

"Does it make me a horrible person to wish that he wasn't gone so often? I mean, having dinner and watching a movie is hardly more important than changing lives in third world countries."

"In the grand scheme of things, no, I guess it's not so important. But to a relationship? Yeah, it's a pretty big deal. Not loving the long distance?"

Kate sighed. "Honestly, I'm just not loving the distance. We don't see each other much to begin with, and then it's just, you know…fun."

"I'm sorry, are you saying you want a difficult relationship?" Rick asked, his mouth falling open.

"No!" Kate laughed. "It's just…I don't know," she shook her head and stared at the ground.

"You'd like to share those parts of your life, which is the majority of it, I'd guess, that aren't all about smiles and laughs?"

Kate looked back at him, feeling like she should stop being so surprised when he pegged her for whatever she was thinking. "Yeah."

"Maybe you just need more time," he said after a pause. "When does he get back?"

"Sunday."

"You gonna tell him about what happened this week?"

"I don't know. We don't talk about work much."

Rick just stared at her. "What do you talk about then?"

"Movies, books…our other interests," Kate shrugged. "I mean, sometimes, if I look like death warmed over, he'll ask. Or if someone dies on the table we just have a stay-in night…but that's only if we happen to be free at the same time. Most cases, I'm back too late, or he's still on shift or…" she petered off.

"I'm sorry," Rick told her.

"For what?" she asked, surprised.

"It doesn't sound like you're very happy, and I like to see you happy…so I'm sorry that you're not."

"Thanks."

They sat in silence for a few minutes, watching people go past, before Rick stood and offered her his hand. "Shall we go, Detective? We could walk to the Zoo."

Kate laughed and took his hand, letting him help her up. "The Zoo? Really, Castle? You want to go to the Zoo?"

He began to drag her in the direction of the Zoo across the park. "Oh come on! You can't tell me that you don't like the penguins."

Kate tried to scoff, but failed as a smile broke through. "Ok, no, I can't. Lead the way." She slipped her hand out of his and linked their arms together as they walked down a little hill.

"So, can I ask you a question?" she asked as they wound around a small pond and past a few food carts lined up along the path.

"Shoot."

"Why did you end it with Gina?"

She felt him stiffen for a second before he relaxed. "Does it sound bad to say it just wasn't right?"

"I guess not."

"We just…we were content. I mean, I like Gina. She's smart, and funny, and beautiful, but we're just not connected, you know? We were doing better than the first time; I was being less defensive and she was slower to go in for the kill, but that didn't change the fact that we weren't in love. In the end, we were fighting over how much we were fighting, and it just seemed better to break it off before it got worse. We still have to work with each other, after all."

"Sounds like it was the right choice."

"I think so," Rick replied as they reached the ticket booth for the small Zoo. "Two please." The ticket man gave them their passes and Rick pulled Kate through the turnstile and into the first exhibit.

"I could have paid for my own ticket, you know," Kate told him as they walked through the reptile room.

"I know. If it really bothers you, you can pay me back."

"I do have enough money to do things, Castle."

"Hey," he caught her arm as she began to walk on without him. "I know you do. I'm just used to paying for things because, well, I'd have to spend obscene amounts of money to even dent what I have. I don't usually think about paying for other people. But really, if it isn't something you're comfortable with, that's totally fine, and I'll make an effort to stop. I'm not trying to be condescending or anything."

Kate considered him. "Let's make a deal. If we're out, you try to remember to ask me if I want to split, and I'll try not to take offense when you inevitably forget."

"Deal," he smiled and stuck out a hand. Kate rolled her eyes but shook on it.

They wiled away the rest of the afternoon looking at the many display cases and tanks at the Zoo and ended up at the Old Haunt for dinner, taking what had become Rick's signature booth in the corner.

"It looks good, Castle," Kate told him as they sat down and took the menus offered by the waiter.

"Thanks. It's a great place, and I'm happy to be able to help keep it alive."

"Doesn't hurt that the whole precinct gets discounts either," she added as she spotted Velasquez across the room with her husband.

"A bar is a place for friends and family. The 12th counts as both."

Kate was about to respond when her phone pinged. "Sorry," she told him as she reached for it. He waved her off and ordered for them when the waiter came. Kate looked down and saw that she had a message from Lanie.

Girls' night tomorrow. No excuses. And not at Castle's bar.

"Looks like I'm having a girls night with Lanie tomorrow."

"Then I suppose," Rick began, but his cell pinged and he fished it out to read the message. "That I'm having drinks and poker here with Ryan and Esposito tomorrow," he laughed.

"And they want us to think that they're not dating," she shook her head as their drinks arrived.

"I figured a beer and milkshake would have been too much, so I got you the beer, and we can have cake or something with dessert?"

"Well played, Mr. Castle," Kate smiled as they clinked bottles.

They ate and talked for hours, rehashing her Mom's case again, talking about Alexis and Martha, discussing movies, sharing memories and doing that banter they both so enjoyed. When they had more than overstayed their welcome (though, to be fair, Rick was the owner) they made their way out and into the chilly night. They hailed a cab and made their way to Kate's building.

Rick walked her in, the doorman smiling at them as they made their through the lobby and into the elevator. When they reached her door Kate turned to Rick and smiled.

"I had a really great day, Castle," she said as she gave him a quick hug.

"Me too. We should do it again sometime."

Kate bit her lip and gave him a small smile. "Sounds good," she said after a pause.

"I've got a publishing thing Saturday during the day and I know you've got some things you'll want to do tomorrow," he said, waiting for her nod. She was glad he hadn't offered to go with her to see Lockwood; she wouldn't have been able to say no. "Maybe Saturday night?"

"Sounds good," Kate replied quickly, almost too quickly.

Rick grinned. "Good. I'll call you tomorrow so we can decide what we want to do. Have a nice evening Detective," he leaned over and kissed her cheek before turning away and getting into the elevator.

Kate watched him go and shook her head as the doors closed, before she unlocked and entered her apartment. It wasn't good that a kiss on the cheek from Castle gave her more butterflies in her stomach than the last time she and Josh had kissed…and more, was it? She sighed as she dropped her things and made her way to the bathroom to think things over. It might not be a swimming pool, but her bath would have to do.