Author's Note: Apologies for the length of time between posts - on this and all my other fics. This is the busiest time of year for me at work, and it has been kicking my ass. But these fics have not been abandoned! Thank you for the support and the reviews!

If Kate Beckett was that determined to make sure Richard Castle couldn't follow her more supernatural exploits, then he figured he'd best learn about those types of things on his own. Which meant walking through a cemetery in the middle of the night – alone. Perhaps not Castle's best idea ever, but certainly far from his worst.

Besides, how else was Nikki Heat supposed to be a kickass monster hunter if Castle had no idea what all went into monster hunting? He supposed he could've asked Faith for an assist – she at least seemed more cooperative than Detective Beckett, and truth be told, he was dying to hear more of her story – but he wasn't drawn to Faith the way he was drawn to Kate.

Oh, Faith was fun. In fact, Castle had no doubt that she was fun in several different ways. Were the writer about a decade younger, he would see the Slayer with the dark hair and the arm tattoo and the apparent rap sheet as a challenge worth pursuing.

Still, the thoughts were nice.

Slipping between tombstones, and noting that none of them were fresh, Castle was about to leave the graveyard in disappointment when sounds of a struggle from the other side of the plot caught his attention. Pulling his smartphone from his coat, Castle crossed to the other side of the cemetery, using a particularly large headstone as cover.

Peeking over the top edge of the stone, Castle saw two men in a knockdown drag-out brawl. One man wore a sleeveless black tee, silver chains dangling from the belt loops of his black jeans. The other man wore a billowy black coat and had an air of familiarity to him, even if Castle couldn't get a good look amid the tussle.

The man in the coat wound up on his back with a grunt, and Castle saw the pronounced ridges and yellow eyes on the other man. Recognition triggered, and Castle stood a little more upright. It looked just like the creature that had attacked him at the book party – the night that changed everything.

To Castle's surprise, the creature had a stake in both hands, hoisting it above his head with the clear intent of jabbing the other man in the chest. Confused, and honestly, not sure what else to do, Castle emerged from behind the headstone, his left foot kicking against the base of it.

"Hey!"

The creature's head shot up, confusion in its eyes. That confusion soon morphed into something more sinister, as the vampire dropped the stake with a snarl and broke off into a sprint, heading right toward Castle.

"Aw, crap," he muttered with wide eyes. His brain told him to run, yet the most Castle could muster was a few awkward steps backward.

So busy trying to extricate himself from the situation, was Castle, that he hadn't noticed the other man getting back to his feet, grabbing the stake that had been dropped, and slipping an arm around the vampire's neck. By the time to hunk of wood had been jammed into the vampire's chest, a stunned look frozen on the monster's face before he disappeared in a cloud of ash, Castle noticed his savior was none other than the P.I. named Angel.

Only…something was a little different about him.

Angel dropped the stake, panting from exertion. Castle had feeling in his legs again, even if adrenaline and fear were still pumping through his veins. He stared at Angel's face, noting the same ridges and feral eyes that he had seen in the monster that had just been dusted. When Angel lifted his head, Castle saw fangs, and he nearly stumbled over a tombstone as he backed up.

"Geez!"

"Richard Castle?" To say Angel was incredulous would put it mildly. "What the hell?"

"What do you mean what the hell?" The writer shot back, his voice raising an octave more than he liked. "What the hell should be my line! You're one of them?!" He shook his head, nervous laughter bubbling from within. "Does Beckett know about this?"

Angel sighed, his face shifting back to its more human visage. "What are you doing here?"

"Book research," Castle's answer was automatic. "What are you doing here?"

"Hunting."

"So…" Castle quirked a brow. "You hunt your own kind?"

Angel shrugged. "The evil ones."

"The evil-?" Castle sighed and shook his head. "Okay, what aren't you telling me?!"

"So much, Castle." Angel shook his head with a smirk and the ghost of a sideways grin. "So very much. But…if you must know…" He leaned in, fighting the urge to smirk when he saw the writer back away from him. "I have a soul."

Castle blinked. "A vampire with a soul." The writer smirked. "God, how lame is that?"

"Don't make me regret saving your ass."

Once Angel started walking off into the night, Castle fell in lockstep with him. "Funny, Beckett said the same thing once."

Angel stopped on a proverbial dime, and Castle nearly ran into his back. But in turning to keep from running in the vampire, Castle caught his left foot on the edge of a tombstone and nearly toppled over. Angel's cold hand on his shoulder was the only thing saving the writer from sure embarrassment and potential injury.

"What is it with you and Beckett, anyway?"

"Book research."

There was that stock answer again. An answer with just enough truth in it for Richard Castle to seem entirely on the up-and-up, when the reality was that it went a little deeper than that. He was attracted to Detective Beckett, sure, but more than anything, she intrigued him. Why someone with her looks and smarts would become a cop, and how in the world she was chosen to be this kickass demon fighter.

Angel's eyes narrowed. "Book research."

"Yeah." Castle placed his palm on the top of the headstone he nearly face-planted over before realizing it was a tombstone and removing his hand as if he had just touched a hot stove. "I've created a new character to replace Derrick Storm. I shadow Detective Beckett for research."

"I see." Angel stuffed his hands into the pockets of his coat, chewing on his lower lip. "Set aside the fact you should've never killed off Storm in the first place…why her?"

Castle blinked. "Why not her?"

"You wanna shadow the NYPD to lend authenticity to your books? Fine." Angel shrugged. "But why Detective Beckett?"

"She's good at what she does," Castle answered with a shrug.

"You mean with a badge or with a stake?"

"Why do I get the feeling I'm being accused of stepping on your toes here?" Castle took a step toward Angel, momentarily forgetting the fact that Angel was a vampire and – soul or no soul – much stronger. "Come on, Angel. Why does my presence in Beckett's life bother you so much?"

Angel faltered. "It doesn't."

"Please," Castle scoffed. "I don't know how old you actually are, but you're a terrible liar, and you're acting like I did in tenth grade when Cecilia Jenkins went to the fall dance with someone other than me."

"I warned you about her."

"And I still don't know why," Castle pressed. "I saw you at the precinct the other day, skulking about in the background. You were looking at her, and I could see something there. Not really sure what – your forehead kind of gets in the way – but I don't buy for a second that you're warning me off of Detective Beckett out of the goodness of your unbeating heart."

Angel's dark eyes flickered to the tombstone Castle was standing next to, arching a brow. "Mr. Castle, what exactly do you know about Kate?"

"I know you just used her first name," Castle answered. "Which no one does."

"Look at the tombstone, Mr. Castle."

More confused than before, Castle reluctantly took a step back and turned his attention to the gravestone – the same one he almost did a nosedive over just a few minutes ago. He did a double-take once he saw the name etched into the stone, his hands instinctively balling into fists as he regarded the vampire again.

"Johanna Beckett."

Angel nodded. "Yep."

"I read about her in the paper," Castle said, returning his gaze to the stone. "Must've been…what, almost 15 years ago?"

"Johanna's her mother," Angel explained. "Kate was home on break from Stanford when she was murdered."

Castle shook his head. "I had no idea."

"Johanna's murder is what made Kate become a cop," Angel cast a sideways glance toward Castle. "I'm sure you thought the same thing I did when I first met her: how does someone who looks like her, who comes from a family of lawyers, become a cop? Homicide, even?"

Castle couldn't tear his eyes from the tombstone. "It crossed my mind. Has the case been solved?"

Angel shook his head. "Official NYPD stance is that it was a random act of gang violence."

Castle finally tore his gaze from the tomb to regard Angel again. "You don't believe that."

"Neither does she." Angel shrugged. "This was one of the first cases I worked when I moved to New York. She wanted me to see if I could find anything the NYPD had missed."

"Did you?"

Angel fell silent, his gaze darkening as he stared at the tombstone. Castle noted the Latin phrase permanently marking Johanna's final resting place before turning his attention back to the vampire, studying the subtle shifts in his pale face and the way his shoulders seemed to tense. Castle cocked his head to the side.

"You didn't, did you?"

Angel turned away from the writer and started walking again, trying not to roll his eyes when he heard the soft footsteps following from behind on the grass. The vampire stopped again, but didn't turn to look at Castle.

"Six months."

Castle frowned. "Six…months what?"

"Kate and I," Angel sighed. "We were together for six months."

Castle shrugged, hoping his legendary poker face extended to middle-of-the-night chats with goody-good vampires. "I didn't ask."

Angel scoffed. "Yeah, you were not asking very loudly." The vampire finally turned to regard Castle again. "Look, Kate and me…we're too much alike. We were wrong for each other. When it was good, it was…" A ghost of a smile trickled onto Angel's pale face. "But when it went bad, oh…it was bad."

"Congratulations," Castle joked. "You just described my first marriage."

"She's headstrong, driven," Angel explained. "As driven as anyone I've seen in a long time. But…there's no balance to her life. It's the job, it's the slaying, it's her mom's case. And I'm not any better."

Castle arched a brow. "Meaning?"

"My soul is a curse," the vampire said. "Long time ago, I ate a Romani girl one night, and her family cast a spell on me. Restored my soul so I could live with the guilt of all the terrible things I did."

"Damned to live out your endless days wracked with despair," Castle mused with a single nod. "Rather ingenious, as far as punishments go."

"That's not the worst part." Angel shook his head. "I experience pure happiness, I lose my soul. I revert back to Angelus."

"Angelus." Boy, Castle wished he'd brought along a notepad and a pen. "And…on the scale of Count Chocula to Vlad the Impaler, how bad was this…Angelus?"

Angel shook his head. "Some things, Mr. Castle, you're better off not knowing."

That non-answer was actually all the answer Castle needed. "So…pure happiness." The writer cast a sideways glance. "What would pure happiness entail, exactly?"

"It wasn't with Kate, if that's what you're asking."

"It wasn't."

Okay, so it totally was.

"Look," Angel said with a sigh, "you're clearly going to be a part of Kate's life for the foreseeable future, so…look out for her, will you?"

Castle frowned. "Are you…asking for my help?"

"More or less." Angel glanced over his shoulder. "So long as you're in the way over there, maybe you can be useful. Captain Montgomery's been acting strange lately."

Castle arched a brow. "Strange."

"I think he's hiding something from Beckett. I just don't know what." Okay, so that was a lie. Between Montgomery's offer and Senator Bracken's visit the other day, Angel thought he had a damn good idea what was going on. "But I have reason to believe it's related to her mother's case."

"You want me to spy on Captain Montgomery," Castle shook his head. "Beckett's boss and one of my best poker buddies."

"He knows who killed Johanna," Angel argued.

"Which would be her business," Castle countered. "Unless you're still on the case."

Angel turned to walk into the night again, and this time the writer didn't follow. Angel glanced at the grass as he walked, his hands trapped in the pockets of his coat. He could practically feel the confusion coming off of Castle in waves, silently wondering if maybe he'd said more than he should.

"Just keep your eyes open, Richard."