Ficlet prompt from anon on tumblr: Castle family and Ryan family holiday together in the Hamptons, kids in the pool and water fight antics

Loud, excited shrieks pierce the air as the five kids splash each other repeatedly. The twins like using the hollow foam noodles to blow water at the girls, and Nicholas loves doing cannonballs close enough to send a wave of water over them. Both Sarah Grace and Lily are opting for more traditional methods of sliding their arms across the top of the water and slapping the surface to send spurts of water at their brothers. One thing is clear to the parents watching from the side of the pool – no matter the choice of how to send water flying at another person, the battle has clearly turned into a 'boys versus girls' fight. It's truly a fight with no losers though, because there is nothing but joy on their faces.

Kate sighs happily. "I'm really glad we were able to all come up here."

Castle, Ryan, and Jenny all nod in agreement.

"Yeah," Jenny smiles, "this has been one of the best weekend getaways we've had in a long time."

Ryan laughs, "And it's definitely better than our Labor Day trip was last year."

Jenny groans. "Literally anything would have been better than that dump. That was the last time I ever booked a trip based just on online reviews. Now I don't go anywhere unless I know someone that's been there. Thank you again for inviting us up here."

"Of course," Castle smiles widely. "We were so glad you could come. The kids wanted Nicholas and Sarah Grace up here to play with, Kate and I were excited to have some company too," he chuckles. "Sometimes on vacation the kids just don't want to hang out with their parents, you know?" he laughs again.

"They'll reach a point where they don't want to hang out with us at all," Jenny sighs wistfully. "At least we have times like these to make memories, right?"

The other parents nod and they all look back at the kids, still happily trying to soak each other in the pool. After a few moments Lily notices them watching and gestures for them to join. "Come on, Mom, Aunt Jenny, help us fight the boys!"

"Yeah!" Nicholas calls out. "Dad, you and Uncle Rick could join our team too!"

The adults all glance at each other briefly, then smile before getting to their feet and jumping in the pool to join their kids, who all yell enthusiastically. The water war continues for over another hour, with many other games added in, like chicken and gator. By the time the two families get out of the pool for the last time that afternoon, they're all happily exhausted. They later have cookout on the beach of hotdogs and s'mores, ending the last day of their vacation perfectly.

As Kate curls up next to Castle that night she feels a slight tinge of melancholy. "I don't want to go home in the morning," she tells him. "I don't want this to be over."

"Me either," he sighs as he hugs her tighter. "But all things must come to end, even good things."

"I know. That doesn't mean I have to like it," she chuckles. "You know what though?"

"What?"

"I'll always remember this as one of the fondest times of my life."

"Me too," he smiles widely. "Me too."