October 13, 2045

The bedroom was cast in a warm amber glow, lit only by the flickering flames of a few candles on the dresser and the light of the moon streaming in through the sliding glass doors. It was nearly full and shining brightly, glistening off the landscape and shimmering in time with the rhythmic cresting of the gentle waves.

Laying in their bed gazing out over the water had never gotten old, even though they'd been living out here in the Hamptons full-time for almost four years now. Not long after Kate retired, they'd made the decision to move away from the city they'd called home their entire lives. It was time for a slower, quieter life.

Alexis had taken over the loft and Connor and Emma, who were now teenagers, spent roughly half of their time there as well, spending the remainder with their father. Connor had just begun his senior year of high school, and Castle was having trouble reconciling the little brown-haired baby boy with the six-foot-tall, baseball-playing young adult he'd become. He knew Jim would've loved the fact that one of his grandchildren was so enthusiastic about the Beckett family's favorite sport.

But as much as Connor and Emma had grown and matured, the biggest change in their family in recent months was the addition of a new member. Matt and Lily had tied the knot two months prior, in a lovely ceremony here in the Hamptons, with the moon rising in the background and the entire property decorated with strands of white lights that mimicked stars twinkling overhead.

After a two week honeymoon in Europe, they had settled back into their apartment in California, where both were well-established in their respective careers – he as a firefighter and Lily as a lawyer. Castle was beyond proud of his daughter and son-in-law, but he did often find himself wishing they lived closer. However, it had been wonderful to have the entire family back in Manhattan for the weekend in celebration of Lily and Matt.

And it was fun to reminisce now as Castle and Kate sat cuddled in the middle of their bed, surrounded by a pile of blankets with Cocoa the fluffy cat – the other recent addition to their family – curled on their feet.

August 20, 2045

Dear Kate,

Lily is married.

I've been through this before with Alexis. I thought it would be easier the second time around. But maybe it's just never easy to watch your daughter get married. I wonder if I'll feel this way if and when Jake and Reece get married? I wonder if it ever gets easier to watch your children grow up and move on with their lives… lives that we're no longer as much a part of?

Matt is great. I'm thrilled that Lily found someone as wonderful as him, and I'm forever thankful that she's in a solid relationship with a man who is much more responsible and mature than I ever was at that age. You told me once that girls who are close to their fathers are likely to end up dating guys just like them, and that terrified me for years. Especially with Alexis.

"You know that's not true, right?" Kate asked.

"That girls end up dating guys like their father?" Castle echoed.

"I mean, maybe that's true," she amended with a shrug. "But in your case it's not a bad thing, even though I meant it to be at the time."

"Except, at the time, you weren't wrong," he argued. "I was terrible husband material. For most of my life."

Kate leaned in to press her lips to his cheek, nuzzled her nose against the day's worth of stubble dusting his skin. "Babe, any woman would be lucky to marry someone like you."

Castle slipped an arm around her shoulders, held her closer.

I have to say, though, it's been comforting and also somewhat amusing to watch you freak out over this wedding. As tense as I've been, you've been a hundred times worse. Ninety percent of the time you're so calm and collected, so I sometimes forget how panicked you can get. I didn't see you immediately before our wedding, but from what I did observe, you were more nervous about this one.

I suppose that makes sense. I wasn't terribly nervous for our wedding either. I just wanted to be married to you, and despite all the planning that went into it, when the time arrived I didn't care about the details. You were there and our families were there, and that's what mattered. But as parents we obviously want our children's weddings to be perfect.

All in all, I think things went according to plan. There were no major catastrophes and only a couple minor hiccups. I'm not even certain Lily and Matt noticed them. Perhaps the biggest drama of the day was when the mother of the bride accidentally drank a little too much champagne.

Kate groaned and rolled her eyes. It turned out she'd become much more of a lightweight in recent years, something she hadn't realized until after she'd lost count of the number of glasses of champagne she'd consumed.

"You were so drunk," Castle laughed.

She ran her fingers through her hair before resting her forehead against the heel of her hand. "My hangover the next morning can attest to that."

"I'm not sure I'd ever seen you that drunk."

"And you never will again," she promised. "I'm far too old to drink that much."

"If you're too old to drink, what does that make me?"

"Age is wisdom, babe."

"Nice save."

Kate smirked and averted her eyes, dropping them back to the last few lines of text on the page.

Drunk or not, it was a beautiful ceremony and I'm so proud of Lily and so happy for them both. But, as usual, it's hard to believe she's already old enough to be married. It seems like just yesterday that she was a little girl, and now she's a lawyer and a wife and I don't think I'm ever going to fully come to terms with it.

"Me neither," Kate admitted. "I never thought I'd feel that way, but I do."

"Then we can commiserate together."

Sometimes I wish the world would just stop for a little while, but I swear it's moving faster and faster every day. I suppose the best we can do at this point is to be thankful for the time we've been given and enjoy every moment of the time we have left.

As long as you're by my side, I know I'll never have any issues with either of those things. You're my life, my love, and my everything. Always.

Love,

Rick.

Kate found herself lingering on the last two paragraphs, re-reading them again and again and relating very easily to Castle's words. How she was five years into her retirement with three grown children, Kate didn't know. It was a place that, for many years, she never imagined she'd be. And though they'd had their fair share of ups and downs, though there were regrets and moments she wished she could forget or do over again or remain trapped in forever, she was immensely grateful for the life that she had.

With Castle.

Thoughts?