Author's Note: Sorry for the length of time between posts; fic writing appears to be slow-going these days. But business is picking up! Review, please!

"One of us should've stayed behind."

"Alexis will be fine, Faith," Buffy called out over her shoulder as she, Faith Lehane, and Kate Beckett patrolled the south end of Central Park – which mercifully was devoid of people at this late hour. The medieval arsenal the three women carried was all for one notorious, and recently-revived, bloodsucker.

One who had a personal past with Buffy and made the mistake of trying to snack on the wrong redhead. Alexis Castle was unharmed, but the near-miss with Spike had all three Slayers on high alert – to say nothing of the teenager's devoted father, whose eyes had held an anger none of them had seen when he learned of the attack.

"Not Red I'm worried about," Faith countered, stopping in her tracks.

"Okay, I'll bite." Kate hoisted the crossbow over her shoulder, stealing a glance at the full moon before turning her attention to the other Slayer. "What's wrong?"

"Just think one of us should've stayed behind with Ricky."

"Oh, so Castle needs a babysitter?"

"Right now, yeah." Rolling her eyes at the looks of disbelief the other two Slayers were giving her, Faith pocketed her stake and approached the duo. "Think about it. Spike went after his daughter."

"Which is why I made him promise to stay behind."

"No offense, Detective B, but his word doesn't mean jack right now."

Something resembling anger flashed in Kate's eyes, and part of her wanted to ball her fists and approach Faith. Physically, Kate was every bit Faith's equal, and seeing as how Kate had actual training of a sort over the years – the Police Academy wasn't the Watchers Council, but still – she was confident she would have the edge. But discretion held her back – as did the knowledge that she was dealing with someone who had done time for murder. Instead, Kate set her jaw and shook her head.

"He wouldn't break his word like that. Not to me."

"It's not about you, Kate." With a sigh, Faith turned to the blonde. "B, if he had attacked Dawn, would you sit on your ass and twiddle your thumbs while everyone else saddled up?"

"No," Buffy answered, "but I'm a Slayer. He's not."

"You think that matters to him?"

Buffy cursed under her breath as realization washed over her. Faith was right; in the short time Buffy had known the bestselling author, he had proven to be both a capable mind and a doting father. In a lot of ways, Richard Castle was the sort of father Buffy had wished for when she was a teenager.

Alexis was clearly the most important person in Castle's life – though Buffy could tell Kate was becoming increasingly important to him with each passing day – so there was no telling what he was willing to do to protect her.

Before any of them could comment any further, Kate's phone went off. With an eyeroll, she pulled the phone out with her free hand. Work always had a habit of butting in when she was trying to get something else done – it was tempting to sometimes ignore her phone, but NYPD regulations forbid it.

"Sorry," she shrugged before answering her phone. "Beckett."

The tone in LT's voice told Kate something was terribly wrong before the words themselves sank in. Kate's eyes widened and she dropped the crossbow in her other hand before cupping her palm over her mouth. Buffy and Faith both approached with apprehensive glances.

"Yeah," Kate said, her voice cracking. "Yeah, I'll… I'll be right there."

Buffy quirked a brow when Kate ended the call and pocketed her phone with a shaky hand. "Kate?"

"Precinct." Tears brimmed in Kate's eyes, and she swallowed hard. "Now."

Angel Investigations…

"The answer is no, Mr. Castle."

"He attacked my daughter!" Castle's jaw set as he approached Angel's desk, hands curled into fists. Despite his broad shoulders and impressive arms, Richard Castle would never be considered a violent, dangerous person. But the fire burning in his eyes, the way his fingernails dug into his palms… he felt like he could take on anyone, anything, and come out the other side.

"I understand that." Angel leaned back in his chair with a sigh. "You said the Slayers went after him?"

At this point, Castle refused to meet Angel's gaze because logically, he knew what the other man was about to tell him. About how the three women were far stronger, far better equipped to handle a vampire than he, that all the rage and protective nature in the world were no match for Spike's strength and bloodlust.

Screw logic, Castle thought, and not for the first time. He hadn't spent the past near-decade and a half raising and protecting his daughter to let some monster with a bad dye job get his paws on her. What kind of father would Castle be if he sat back whenever the apple of his eye was attacked?

"This isn't just some vampire," Angel argued as he rose from his seat. "Spike is one of history's most ruthless and notorious monsters." Angel's shoulders hunched as he spoke, mostly because his brain was racked with confusion; how had Spike been brought back to life, and how had he been brought back without a soul?

He had a theory, but he didn't dare voice it right now.

Too anxious to sit, Castle had spent his time in Angel's office pacing back and forth. He now found himself staring at all the photographs hanging off the wall, chronicling the P.I. over the years, surrounded by a small ragtag group of allies. They appeared to be a family of sorts, even if they weren't always looking all that happy.

The green-faced man with the red horns and the splashy suits was of particular interest, and in different circumstances, Castle would've asked about him. But he still shook with rage and adrenaline, and if Castle was being honest with himself, he was mad at Angel for not cooperating with him.

"Do you know what it means to be a father, Angel?"

Clearly, Angel didn't – after all, vampires couldn't have children. Yet when Castle turned his attention from the wall to the vampire, he noticed that Angel wasn't meeting his gaze. The broody glum look returned to Angel's face, his hands clasped over his midsection. Angel was chewing on his lower lip, clearly holding something back.

There was a story there. A story he wanted to hear.

Before Castle could press any further, though, the phone rang. The shrill ringing startled both men before Angel grabbed the receiver. "Angel Investigations, we help the helpless."

Angel's eyes widened and he sat up straighter in his chair. Whatever he was being told, it was apparently serious. "What?!" The vampire bolted from his seat, grabbing the black overcoat that was draped over the back of the chair as he hung up without saying another word.

"What's going on?"

"Go home, Richard."

"What?" Castle frowned. "What about my daughter?"

"No offense, but your daughter is the least of my concern right now."

Before Castle could respond, Angel sped out of the office and slammed the door behind himself. He caught sight of an armory in the corner, a chest stuffed full with broadswords, crossbows, and other various weaponry. Part of Castle wanted to load up on weapons and go after Spike himself; in fact, it was very tempting to do just that.

Screw everyone trying to protect him. What kind of father would Castle be if he let someone attack his daughter without repercussions? Then again… he had made a promise to Kate. Something was developing between them; he wasn't sure what, but it was definitely there. His own feelings for her had blossomed since he had weaseled himself into her life.

And really… if he went back on his word to Kate, what did that say about them? About him? No… as badly as Castle wanted to make sure Spike paid for what he had done, he gave Kate his word that he wouldn't go after him.

So despite every impulse screaming for him to do otherwise, Castle simply turned and walked out of Angel's office.

The Twelfth…

As soon as the elevator reached the Homicide floor, Kate Beckett pushed her way through, in a full sprint before the other two Slayers behind her could follow. Tears had burned at the edges of her eyes since receiving the call, but Kate hadn't allowed them to fall. Not even as her heart pounded against her ribcage, not even as her limbs threatened to give out.

She ignored the paramedics tending to Ryan and Esposito, pushing past them. By the time she reached her desk, which was roped off with yellow crime scene tape, her heart skipped a beat and her stomach did a back flip. Kate stopped in her tracks and cupped a hand to her mouth, choking back a sob when she saw Roy Montgomery's body sprawled out over the surface of the desk.

"Roy…" Another sob burst from Kate's lips and she felt both Buffy and Faith grabbing her arms. Tears began streaming down her face. She felt both women tug on her arm, trying to get her to distance herself from her own desk, but Kate wouldn't budge. Other than her shoulders rocking with each sob, she was still.

"Roy!"

Her voice cracked as it carried throughout the bullpen, calling the attention of the detectives and uniforms trying to pick up after the chaos. The body count was relatively low – aside from Montgomery, there were two dead uniforms. No one dared say a word; the only sounds in the precinct were the occasional groan of pain and Kate's crying.

Her knees wobbled and nearly buckled. Her vision clouded by emotion, the streaks on her face burning with despair, Kate tore herself from the other Slayers' grip before slicing through the tape and sinking into her chair. A pool of dried blood stained the hardwood floor, the end of a trail that had run from the side of Montgomery's neck all the way down the side of the desk.

"Letter opener punctured the carotid artery," the ME on scene, a balding man named Sidney Perlmutter, said from the other side of the crime scene tape. "He bled out within seconds."

Clenching her jaw and squeezing her eyes shut, Kate didn't notice when Detectives Ryan and Esposito approached the scene. Esposito was holding an ice pack over her face, while Ryan's arm was hoisted into a crude sling. Their eyes were red and puffy; at some point, they had the same reaction Kate was enduring.

"Who?" Kate's voice cracked. "Who did this?"

"Some British guy," Esposito said, the sound of his voice bringing Kate back to the here and now. "Black leather overcoat, platinum blonde hair."

"Said his name was William Pratt," Ryan added.

Kate's eyes flickered to the other two women, watching as Buffy cupped a hand over her mouth and stepped back. Her eyes had widened in shock and disgust. Faith snarled and curled her hands into fists before she began pacing back and forth in the bullpen, her combat boots stomping against the floor.

"Spike."

Ryan frowned. "What?"

Kate pushed herself out of her chair, stepping on a chunk of broken ceramic. She knelt down to pick up what was left of it, another wave of tears springing to her eyes when she saw it was a trunk from one of the elephants. One of the last ties to her mother… destroyed.

"His name is Spike," she said through a trembling lower lip.

Esposito shook his head. "Who the hell is Spike?"

Ryan turned to the other two women standing at Kate's desk. "And what the hell was up with his face?"

Buffy turned to Kate. "How much do these two know?"

Kate shook her head and swiped under her eyes. The tears wouldn't stop falling, even as they were burning her eyes on the way down. She sniffled and sucked in a ragged breath, unable to tear her gaze away from the dead captain on her desk. "Nothing."

"What?" Esposito closed the distance. "What don't we know, Beckett?"

Buffy gently placed a hand on Esposito's arm, pursing her lips at the glare he shot her way. "Spike's a… he's a vampire."

"A what?!"

"Come on," Faith told the other two detectives, opening the door to one of the conference rooms and cocking her head to the side. "Buffy and I will explain everything to you. Let's just… give Beckett some space."

Esposito turned to look at Kate once more, taking in the wet streaks on her face and the zoned-out look in her eyes. She looked like she wasn't even in the same room as everyone else, the shock of Roy Montgomery dead and sprawled out on her desk apparently too much to bear. Not that he could blame her.

In fact, when Spike had first unleashed hell on everyone, it appeared random, senseless. But once he saw Detective Beckett's desk, things turned personal. For no other reason than that, Esposito wanted answers, even if he knew next to nothing about the other two women.

So he clenched his jaw and sighed before turning to walk into the conference room, slapping Ryan on his good arm. "C'mon, bro. Let's get us some answers."

Buffy led the two detectives into the conference room and Faith followed. Before she shut the door, though, Faith pulled out her smartphone and shot a quick text to Castle. Once the message sent, Faith sighed and pocketed the device before lowering and closing the blinds.

Now in her relative solitude – kept company only by Montgomery's body and the coroner's staff working the scene – Kate sniffled and shook her head. Her mentor dead, her link to her late mother in tatters on the floor. Spike had sent her a message, whatever it was. Why, she didn't know; clearly, the vampire had history with the other two Slayers – Buffy especially – but what was his beef with Kate?

They had only thrown down that one time in the alley, and honestly, he wasn't nearly as dangerous as everyone kept telling her he was. Or at least, that had been Kate's thought before he waltzed right into the Twelfth and went on a rampage.

"Detective?"

LT's voice cut through Kate's haze, and she looked up with bloodshot eyes. His eyes were just as red and raw, and he gave a sympathetic smile that more closely resembled a grimace.

"This… this is for you." He handed Kate a sheet of yellow paper in an evidence bag. "We found it on Captain Montgomery's body."

Nausea nearly doubled Kate over as she took the bag from LT with a nod of thanks, not trusting herself to open her mouth without either vomiting or losing it all over again. She sucked in as deep a breath as she could, even with the weight of the moment crushing her, her fingers shaking as her eyes scanned the paper.

Kate gagged. He had written her a note, and he had used Montgomery's blood to do it.

Sorry about your captain, love. It should've been you.

William sends his regards.

Castle's loft…

In the hours since Castle returned home, he had tried to get some writing done. Even though Heat Wave was in Black Pawn's hands, going through revisions and formatting and everything else to get ready for launch, Gina had already been on his case about writing another book. Why, he didn't know, but he thought starting another Nikki Heat book would calm him.

After all, the closer he and Kate had gotten in recent weeks, the more vocal his muse became. Nikki Heat was calling out to him at all hours, and it was all he could do to jot everything down. He easily had enough ideas for about ten more Nikki Heat books.

Yet here he sat, empty scotch bottle on his desk and a blinking cursor mocking him.

The anger had not been soothed with time, and alcohol had not extinguished it. He couldn't get the idea of that monster going after his daughter out of his head, and even though he made himself stay put at his desk, determined to keep his word, he was too busy imagining himself setting Spike on fire to really do Nikki Heat justice.

Castle closed his laptop with a sigh, leaning back in his chair and staring out the window. Storm clouds were rolling in, covering what had been a bright moon. He glanced at the clock, seeing that it was nearly four in the morning. None of the Slayers had returned, Castle had just realized, and it gave him pause.

Were they still hunting after Spike? Or had something else come up?

His smartphone chimed with an incoming text message, the sound startling Castle and momentarily snapping him out of his scotch- and anger-induced haze. He ran a hand over his face and stifled a yawn, seeing that the message was from Faith.

When his eyes scanned the words, Castle went cold.

Captain's dead. Detective B's gonna need you.