Title: Smile Big

Author: Maggienhawk

Disclaimer: If Castle was mine, we wouldn't be counting down the hours until the premiere.

Summary: Castle makes a tough decision and reflects on it 10 years later. *Spoilers for season 4…don't read if you are unspoiled*

A/N: It always amazes me when I sit down and start writing how my stories run away from me in an entirely different direction than where I intended on going. Enjoy!

He could never get sick of the playground. All those years ago, he would spend hours there with Alexis, watching with her as she climbed around like a monkey, pushing her on the swings, chasing her around, listening to her laugh with glee. And now, he gets to repeat it all with his three year old granddaughter, a spitting image of her mother at that age. He watches from the swings as she runs around with the other kids, laughing gleefully.

It's not exactly how he pictured his life at this point. He always figured he'd get married again; settle down finally, maybe think about having another kid. And for awhile, it seemed, he knew exactly who he would share that life with. But that's not the way it played out.

Ten years. It was ten years ago they sat on these every swings. She told him that she was open to a relationship, but she wasn't in the right place for it. She needed to close her mother's murder. She needed that closure. He could understand that. He could accept that.

Until he got the call. They threatened to kill her if she didn't back off. And he had to make a choice. Either support her in her search for her mother's killer and possibly lose her. Or, discourage her and never get to truly have her, but she stays alive. It was the hardest and yet the easiest decision he ever had to make.

He remembers the day vividly. He went over to her apartment, and told her about the call. If anything, it made her even more determined to find them, to make them pay. Eventually, he calmed her down enough to get her to listen to him.

"Kate, I know you want justice for your mother. I want it, too," he started, sitting next to her on the couch. "But so many people don't want you to walk down this road, to give up your life to finish this. Your father, Esposito and Ryan, Lanie, me. We all love you too much to lose you to this. Think about how you feel about losing your mother, and that's how we will all feel if we lost you."

"Rick, you can't guilt me out of this." She brushed a tear that escaped from her cheek. "And I need the closure to move on, to move forward with this," indicating to the two of them.

"That's why I'm walking away."

She said nothing, just had this hurt, shocked expression on her face.

"I can't help you find your mother's killer, knowing that they're after you, even if I'll benefit from it in the end. If something ever happened to you, Kate…" he trailed off, taking a hold of her hand

"You'd feel the guilt for the rest of your life," she whispered.

He nodded. "I can't in good conscience stay."

She pulled her hand away, running it through her hair. "This…this just isn't fair. I just can't win either way. Either I let down my mom, or I lose you."

"No one ever said life was fair."

More tears began running down her face. "No, I guess they didn't."

He stood up to leave, and she got up and followed. When he reached the door, he turned around, grabbed her hand and pulled her closer. Softly, he caressed her cheek. "Listen, I know you. You'll never stop looking. Just go slowly and stay under their radar. I…I hope that you find them. You deserve it."

All she could do is nod as he leaned in and brushed his lips to hers.

And then he turned and left, and tried so very hard to never look back.

Alexis went away to college, he continued writing Nikki Heat (he did have plenty of material to work with), and he dated a bit, but nothing too serious, because no one could compare to her. No one ever came close.

But he got something back when Alexis brought home a beautiful little girl, and he finally really had someone to live for again. He put so much effort into helping raise little Amelia, that eventually he didn't think about Kate every day.

He is jarred out of his trip down memory lane as his granddaughter runs and jumps onto him, causing them to swing about wildly for a minute. She's telling him about her new friends, when he looks up and sees her staring at them from across the street.

She's dressed for work, and Esposito is trying to get her attention, but eventually he looks across and realizes why she's ignoring him. A small smile graces his lips, although neither Kate nor Rick see it, and he takes a few steps back, waiting, watching to see what will happen.

Rick picks up Amelia, and starts across the playground, but she's quicker and bolts across the street, dodging the midday traffic. She walks quickly from the sidewalk to where he's standing and stops a few feet away.

Neither have any idea what to say.

Amelia saves the day, "Who is that pretty lady, Grandpa?"

Her eyes widen when she hears the moniker.

He laughs, and looks at his granddaughter, "She's a very good friend of mine. Amelia, this is Kate." He looks to Kate, "Kate, this is Amelia."

Kate, still reeling from the new information recovers, "It's so nice to meet you, Amelia."

"It's nice to meet you too, Kate." She turns to look at Rick. "Can I go play some more?"

He smiles, and puts her down. "Of course you can. Be careful." And she runs off, leaving the two adults on their own.

He starts, "It's been too long."

She nods, "Way too long."

"Come on, let's go sit down." He leads her to the swings that he just recently vacated, and they both take a seat, the swings swaying gently underneath them.

They talk for awhile, about Alexis and Amelia, Esposito and Ryan, her job, his books. She still reads them, considering he's sent her every single one, signed of course, since he left.

They fall into an easy silence, just watching Ameila and some of the other kids run around the playground, playing a little game of tag.

She's the one to break the silence. "I got him."

His head whips around to face her, eyes wide. "You did? I didn't know…I didn't hear."

She nods. "We tried our best to keep it out of the press as much as we could, given his position, the danger." She finally meets his eyes. "It was one of the happiest days of my life."

He smiles. "I bet it was. I had always hoped you'd give her the justice she deserved."

"I know you did. And it helped keep me going, even when I felt like there was no hope." She lets her eyes fall to the ground. "Knowing what you had given up…I had to beat the odds. I couldn't lose you both. So, I kept going, under the radar, like you told me."

"And I'm proud of you, and I'm sure she is too." He reaches out and grabs her hand, squeezing it a tiny bit.

They sit there for a little bit longer, until Amelia walks up, rubbing her eyes and saying she's hungry. He lets go of her hand, reaching out for his granddaughter's. They both stand simultaneously and turn to one another.

"Don't be a stranger," he says. "I miss you, all of you."

"We miss you too, Castle," she smiles. That beautiful smile.

He nods, and turns to walk away. She watches him, but as he reaches the sidewalk, she calls out, "Rick!"

He turns, and sees her sprinting towards him, and all of a sudden she's in his arms and her lips on his. He instinctively drops Amelia's hand to wrap his arms around Kate as he deepens the kiss.

Aware of their surroundings, she breaks the kiss after a few seconds, and takes in his shocked facial expression. She pulls back slightly. "I'm sorry, I…I just…"

"Don't." He quiets her with a finger on her lips. "Why don't you come over for dinner tonight? Alexis will be picking up Amelia in a little while. We can…catch up some more."

She can see the double meaning in his eyes and smiles. "That sounds…perfect."

They settle the details, and she walks away, but not until she gives him another small kiss. He smiles as he watches her cross the street and get into her car.

He looks down, and grabs Amelia's hand, and they begin the short trek home. Halfway there, Amelia speaks up. "Grandpa?"

"Yes, sweetheart?"

"I like her."

He raises his eyebrows as he looks down at her. "That's good, because I like her too. Is there any reason in particular you like her?"

"Because she made you smile really big."

He laughs a big hearty laugh. "Yes, she does make me smile big." And they continue their walk home in a happy silence as he thinks how lucky they are. And how much he loves that playground.