Naked Heat wound up being the last Nikki Heat book, contract be damned. Richard Castle just didn't have it in him to write another one. The second one took just about everything out of him.

To be more precise, he'd grown so emotionally attached to the inspiration for Nikki Heat that when he saw Detective Beckett find her emotional haven with another detective — some square from Robbery named Demming — it shook him far more than he'd anticipated.

So no more Nikki Heat books. No more shadowing Detective Beckett. No more Gina, even; when he broke off their attempt at reconciliation, shortly after the release of Naked Heat, it also marked the end of their professional relationship.

Over the past five years, Castle found a new publisher and a new genre. He'd tried to avoid the vampire craze, but the dollar signs — and a burst of inspiration — wrought Jackson Blood, namesake of the bestselling Tainted Blood.

There have been three Blood books, including the just-released Soaked in Blood. Critical acclaim was through the roof; book sales likewise. It made getting Alexis' tuition bills from Stanford more bearable.

Martha's rent, borne from the success of her acting school, also helped.

Castle lost track of how long he'd been signing books — he could almost feel the stubble as it grew into his cheeks — and every fan sounded exactly the same.

I'm your biggest fan!

I love your work!

Why did you kill off Derrick Storm?

Man, when's Nikki Heat coming back?

"So…vampires, huh?"

The voice brought Castle to a halt mid-signature, and when he looked up, he couldn't believe his eyes. Detective Kate Beckett, from the NYPD's 12th Precinct. Her hair was short again, flared out at the ends like when they first met. Castle felt a smile tug at the corners of his mouth, suppressing it by clearing his throat.

"Detective." He tried to keep his voice neutral, signing another few books before the person in charge of the store cut off the line and told everyone it was time to go home.

Was it closing time already?

Castle said his thank you's and goodbye's to everyone who put the signing together, even joking that in the future, people should bring physical copies of his book. He had mistakenly signed three Kindles and two iPads that day.

Castle pushed through one of the back doors, eager to get home. No way his past had just come back on him like that in there. No, he'd imagined that; there was no way the woman he walked away from five years ago and hadn't heard from since would just show up out of the blue.

But the voice brought him to a halt again.

"What, you shadowing Buffy now?"

His shoulders slumped. Castle turned around with an exasperated sigh, regarding Kate again. Her dress was more formal than in years past. A black tie hung around her neck, and his own latent curiosity nearly got the best of him.

"It's good." She held up her copy of the new book. "Nice to see you finally letting your imagination take over, instead of just basing all your characters on people you know."

"People I knew," he corrected, pushing past Kate and walking across the street to a nearby park. There was an empty swing set in the park, and he took a seat there, secretly hoping that was the end of their interaction.

She sat in the swing next to his. No such luck.

"You never called after that summer." A simple statement of fact. No ulterior motive. No accusations.

Castle shrugged. "Neither did you."

Kate looked down, her fingers absentmindedly flipping through the pages. "Touche'."

The pair sat in silence, which given their proclivity years ago for witty banter, constant back-and-forths, and undeniable chemistry was pretty jarring. They stole glances at each other, and there were a lot of things Castle wanted to say, but couldn't bring himself to.

In fact, it was Kate who broke the silence.

"How's the family?"

Castle stared straight ahead. "Good. Alexis loves Stanford." He tried to ignore Kate's smile when he mentioned her alma mater. "Martha's as happy as I've ever seen her, teaching."

Kate studied Castle's features, a small frown creeping onto her face. "And what about you?"

"What do you mean?"

"I haven't seen you on Page Six since you fired Gina." She leaned forward, hoping to catch a glimpse of his eye — anything to get him to look at her. "What happened to the goofy, fun-loving playboy that I—"

She cut herself off. Oh, sure…now he was going to look at her.

"I just don't remember Richard Castle being so grumpy."

She was teasing. He knew she was teasing. But that didn't stop the anger from threatening to boil over. He sucked in a deep breath to keep it in check, stealing a glance.

"It was Demming, wasn't it?"

He frowned at her, startled by how frank she was — and how that name seemingly came out of nowhere. Castle sucked in another ragged breath, his hands clasped together in his lap. He couldn't think of anything to say, but he figured his non-answer was all the answer she needed.

She nodded and stared at the ground. "I broke up with him, you know." She swallowed, tried to ignore the hole his eyes were burning into her. "The day you, uh…"

Understanding washed over Castle. He sighed, closing his eyes — which only made the bags more visible. He was physically exhausted; the publicity push for Soaked in Blood had run him ragged. It seemed like the marketing got more intense with each book he wrote, which was weird, because he was pretty sure he had the name recognition now that the words "new Richard Castle book" would suffice.

Why did he feel guilty all of a sudden?

"And when you said you wanted to talk…"

She averted her gaze again. "Yeah."

"I guess we missed our chance." Castle smiled, but there was no humor or joy in it. It didn't even reach his eyes.

"Maybe." Kate shrugged, finally meeting Castle's look. His eyes flickered briefly, but he held his gaze. That was something. "Maybe not. I mean…I'm here, aren't I?"

"And why is that?" No accusations. No anger.

She shrugged, her fingers idly tracing over the cover of his book. "Guess I got tired of just…letting things slip by. It doesn't work to solve murders, and I guess it doesn't work for anything else in life…does it?"

His featured lightened considerably, and he could feel the iciness beginning to melt. "No, I guess not."

She stood, the book clutched under her arm. She held out a tentative hand toward Castle, and when he looked up, he saw hope filling her eyes. Awe crept into his, and he felt a grin tug at the left corner of his mouth.

"You wanna go get some coffee, Castle?"

He stood, taking her hand into his. The contact was light, and brief, but despite himself, he felt like something was happening. He didn't know what, or why, or where from, but there was something going on here…and what kind of writer would he be if he didn't see this story through to the end — even with the unexpected epilogue?

"Lead the way, Kate."