I got the idea for this fic from a list of post breakup AUs (link on my profile) and tweaked it to fit Castle and Beckett's relationship. Thanks to Pigeon for being the best editor and friend I could ask for.

As they walk down the stairs together, Beckett starts to thank Castle for his help finding Eliska Sokol's killer.

"Thank you, Castle. I, uh, I never would have been able to solve this case without your help." She pauses and considers what to say next, knowing it's likely the last conversation they will ever have. "Well, uh, good luck on your next book. I know you'll do it proud."

Castle is dumbfounded by her sincerity but manages to smile and say, "Thanks."

The silence that follows is filled with the things neither of them is quite brave enough to say out loud. Finally Castle holds out his hand and Beckett takes it with a reserved smile.

"You take care of yourself, and… give the boys my best." Beckett isn't sure how he intended to end that sentence, but from his change of tone it is clear Castle decided to go a different route. She promises she'll relay the message.

The handshake ends shortly after that and Castle walks across the lobby alone. At the doors he glances back to see Beckett on her phone, likely getting a call about another case. With a little regret Castle pushes past the door and focuses on his next book, his new obsession. Goodbye, Nikki Heat; Hello James Bond.

Several months later…

Castle walks through Central Park, coffee in hand, ruminating on what he just heard from Paula. The publishers loved his take on the British Secret Agent. He submitted the first draft a few nights ago and was still waiting on more critical feedback to do rewrites, so for now he was happy to take in the morning air and not be holed up and chained to the computer.

Based on how this book ended, he had a few ideas of where to take the next one. In fact, it was already half written between the outlines on his computer, sticky notes on his fridge (and the bathroom mirror), and ideas floating around in his head. If the weather weren't so nice he'd probably be inside trying to gather everything and sort it out while he still had the spark. But with the sun shining so bright it seemed everyone decided to come outside this weekend.

Just in this part of the park Castle could see families having picnics, couples holding hands, children playing soccer, people jogging, and a giant golden retriever running right towards him.

He sees it coming from a distance but Castle still stumbles back when the dog launches itself at his face. He drops his coffee to catch the dog, but otherwise there's no harm done. He laughs at its energetic tail wagging and gladly kneels to give it a belly rub.

"So who do you belong to, buddy?" Castle asks, checking its collar for a tag.

"Sorry!" a woman's voice calls, sounding breathless. She sounds so familiar. "I am so sorry, Rook is never like this with strangers!"

"It's no problem, Beckett. I see you got a dog." Castle looks up and gives her a knowing smile.

Beckett is speechless. Her face turns bright red with embarrassment and she just barely chokes out Castle's name in response. He holds his hand out for the leash hanging in her hand and she passes it to him, still trying to compose herself. It's clear she never thought they'd come face to face again.

Once the leash is securely clipped to Rook's collar, Castle stands and hands it back to Beckett.

"How are things back at the precinct? I kept meaning to stop by but a certain secret agent has been demanding most of my time."

"Fine, everything's fine. Ryan and Espo, Montgomery, Lanie, we're all good. Things have been hectic with this case for the past few weeks but we finally caught the guy so we're all taking a break," Beckett replies, sounding distracted. Castle notices she looks in his direction as little as possible and tries to not feel too smug about it.

Beckett spots the spilled coffee her dog tries to drink and finally makes eye contact with Castle.

"I'm sorry, did Rook – um, did my dog do that?" she winces. Castle momentarily ignores the dog's name to give her a break.

"Yeah, don't worry about it. It was almost gone anyways." He picks up the now empty cup and looks for a trash can. Instead he sees a coffee cart not too far away and gets an idea. "But we could get more and you can tell me about that case you were working on. My treat."

"No," Beckett blurts. "My dog, my treat."

Castle nods in agreement and they start walking as Beckett describes the crime scene and initial clues. He starts pelting her with questions, but they are always perfectly timed and coincide with what she was about to say or help her recall small details she almost left out. They way they're talking is so natural; it's as if they had left off a conversation and were just now picking it back up.

By the time she wraps up, they're sitting on a bench together, coffee cups empty. Rook is asleep at their feet and they're both feeling ready for lunch. Castle is about to suggest Remy's when Beckett's phone goes off.

"It's Espo," she says, taking the call. She's very aware that Castle is pretending not to listen while petting the dog, and as she hangs up she feels a bit sad their coffee break has to end. "There's been a murder uptown. I have to go, but it was nice to catch up with you."

"It was very nice. Next time I'll get the coffee," Castle says. He offers his hand and she shakes it, smiling at next time. Then he reaches down to pet the dog and gives her that mischievous grin. "Goodbye Rook."

Without another word they part ways, and Beckett is relieved to have avoided the awkward conversation of why she named her dog after Castle's fictionalized persona. She had very specific, defensible reasons for doing so, but those reasons would not stand up to Castle's inflated ego.

Beckett stops by her apartment to drop off the dog and have a quick lunch before heading to the crime scene. When she arrives, she scopes the crowd as usual before crossing the tape and finding Ryan and Espo huddled together with matching frowns. She asks about the body and they give her all the details, but nothing explains their sour expressions. Finally she asks what's wrong, and in response they both point behind her.

Beckett turns around and sees Castle holding two coffee cups and walking straight towards her.

"Montgomery just called and said the Mayor is pushing him on us again," Espo says.

"Yeah, it seems he didn't get enough info the last time around and wants to do some follow-up for his next book," Ryan adds.

As he approaches, they go talk to Lanie so Beckett is thankfully alone when Castle comes up and presents her with the coffee.

"Detective Beckett! Nice to see you again," he says with a smile.

"Castle, what are you doing here?" she asks sharply, refusing to take the coffee.

"Didn't you hear? I'm starting a new Nikki Heat book," he replies, eyes sparkling. "My publisher offered me a deal since the Bond thing is going so well, and I already have a story in mind."

Beckett rolls her eyes. "You're a fiction writer, Castle. Go write some fiction. I doubt you got to trail any British secret agents for your last book, so you can write this one without following me again."

"I'll admit, research for Bond was mostly done through clandestine meetings with my intelligence contacts on public transportation or untraceable online chatrooms. It worked, but secondhand information just can't compare to being in the field."

"Well you've 'been in the field' before, so why–"

"Beckett, if you answer just one question I'll go away and write this book without one more word to you," Castle interrupts. Tempted, she asks what it is. "You have to answer honestly, and completely, or else I'm gonna stick with you for this case and as many more cases as I need to write a different story than the one I have in mind."

Beckett doesn't hesitate, as this was Castle's usual theatrical nature after all, but she regrets it immediately.

"What is your question, Castle?"

"Why did you name him Rook?"

She really should have seen that coming. That small knowing smile on Castle's face is maddening. Beckett either has to admit why she named her dog after her favorite author, or she has to put up with him hounding her for the next few weeks – or months.

Beckett takes the coffee from his hand and seals the deal. "So our victim is Linda Russo. She's a customer relations worker at a cable company."

She turns around and heads down the alley, knowing Castle will follow her like a loyal pet... a golden retriever.