"When black cats prowl and pumpkins gleam,

May luck be yours on Halloween."

"Beckett, no," he whines, warily eyeing the creature in her hands, nuzzling into the cup of her palm. "Everyone knows black cats are bad luck and it's Halloween. You're practically ensuring our deaths right now."

Kate huffs and finishes cleaning up the kitten's paws, ensuring the soft pads are free of their previous crimson stain, and scratching behind the animal's ears. They had found the cat at the crime scene earlier this morning, no collar or signs of ownership despite his presence in the victim's apartment.

They had caught the killer, but the kitten has still gone unclaimed.

"You're seriously taking it home with you?" Castle presses, sounding sincerely distressed, but she merely rolls her eyes.

"Yes, Castle," she sighs once again, lifting the pet carrier back onto the slab in Lanie's morgue, where the cat had spent most of his day. "He's only a couple of months old and no one else volunteered. I wouldn't expect you to encourage ditching a helpless animal."

He scoffs in offense and she smothers her grin.

"I'm not encouraging abandoning him, but just – take him to a shelter?"

"No, Emerson says she might want him if her landlord approves, so I'm babysitting for now," Kate murmurs, guiding the cat into the carrier with surprising ease, stroking the fine black hair on his head before easing the door shut. "Besides, I'm more than capable of protecting myself from bad luck and evil spirits and whatever else you were going on about."

"Did I mention that it's Halloween? Aka the night when said spirits roam the earth?" he continues, on her heels when she draws the carrier from the metal table and starts towards the morgue's exit.

"Then maybe you should come with me," she hums, already smirking as she glances back to him over her shoulder. "Aid in protecting me from any potential horrors that may befall me during the witching hour."

Kate chuckles wryly under her breath once they're standing on the sidewalk and she's hailing a cab. Superstitious as he's proven to be, she knows Castle won't have the guts to defy his own ridiculous fears, but when he says nothing, she cuts her eyes to him with an inquisitive quirk of her brow.

"Don't worry, Beckett," he states, puffing his chest out and squaring his shoulders. "I got your back."

The amusement falls straight off her face.

"What? No, Castle, I was kidding-"

"Ah, too late," he quips, the corner of his mouth twitching, and damn him. "Sergio may be bad luck-"

"Sergio?" she repeats incredulously while a cab slows to a stop in front of them.

"The cat," he replies, nodding to the carrier in her grasp and opening the door for her. "Suits him, in my opinion, but as I was saying - despite his unfortunate appearance, hopefully together we can ward off the negativity energy he attracts from the universe."

Kate casts her gaze to the evening sky, momentarily ponders how she ended up here with a supposedly unlucky cat and a ludicrous writer both accompanying her home on Halloween night, and steadily ignores the foreign comfort that bleeds through her chest at the idea of Castle joining her tonight.

After Tyson… she preferred to keep him near.

Though, it didn't mean this is how she had planned to do that.

"You slide in first," he prompts, brushing his hand at her bicep, almost causing her to stumble in her four-inch heels. "Then Sergio can sit between us-"

"His name isn't Sergio," she mutters, but if she's being honest, she does quite like the name. Would have picked it herself if she'd thought of it first, but like hell is she telling Castle that.

He follows her into the cramped backseat of the cab, waits until she gives her address to the driver to shoot her a smile in the fading light.

"We'll stop on the way, grab some Halloween candy and cat food."

She rolls her eyes once more and slumps back in the seat, turns her attention to the window, but temporarily fostering a cat with Castle on Halloween doesn't sound so bad.

Not bad at all.

Castle chuckles as Sergio pounces on his chest, pawing at the buttons of his shirt, and runs his hands down the cat's small but prominent spine.

"Oh yeah, Castle," she states, standing over him where he lays across her couch, two glasses of wine in her grasp, and oh, he so wishes she didn't have a boyfriend right now. But that's nothing new. "He's a total demon."

"I didn't say he was a demon, I said he could elicit the presence of them," he corrects, glancing back to the cat that is still just a kitten staring up at him with those glowing yellow eyes. "But maybe you're an exception to the rule, huh, Serg?"

Beckett shakes her head, but lowers one of the wineglasses to the coffee table.

"So what's your plan, Rick? Camp out on my couch all night?" she questions, one of her eyebrows arching as she takes a sip of her wine, and he tries not to watch the line of her throat ripple when she swallows, tries even harder not to acknowledge the spark of heat in the pit of his stomach the sound of his name in her mouth strikes.

"Perhaps," he muses, roving his eyes over the interior of the one bedroom apartment, naked walls and excess bare space, unloved and unlived in. "I don't necessarily feel comfortable leaving you alone here on a regular night, let alone on the day of the dead."

"You do know Dia de los Muertos is different from Halloween, right?"

"Yes, but it's especially hot that you know that," he tosses back, jostling Sergio with a rumble of soft amusement when Kate rolls her eyes, nudges his foot with her knee.

"Scoot over," she murmurs, watching him cradle the cat to his chest and shift into a sitting position to make room for her on the cramped couch he knows she's far from crazy about. "You're getting attached."

"I am not," he protests, but Sergio is nudging to fit beneath his chin, purring into the column of his throat, and okay, fine, he may be just a tad attached to the unlucky kitten after just a few hours, but- "So are you."

"I don't have the time for a pet," she sighs in lieu of an admission, her arm stretching out towards him to stroke along Sergio's spine. "Did he eat any of the food?"

"Not yet, I'm going to try again in a few minutes," Castle answers, rubbing his thumb along the harsh bone of the kitten's cheek. "We may need to take it out of the can, put it in a little bowl or feed it to him with a syringe."

Kate nods, the expression claiming her face thoughtful while she studies the cat that's barely larger than his palm, and props her elbow atop the head of the sofa. "Must have been an alley cat, lost and looking for a safe place."

"Lucky he ended up with you on his case," Rick quips, watching with triumph as her lips curl into a smile that she tries to smother, one that abandons her mouth when her phone begins to vibrate on the kitchen counter a few feet away.

She exhales, long and heavy and he knows even an unexpected call from dispatch wouldn't elicit that kind of reaction, and pushes up from the sofa to check the caller ID.

"Precinct?" Castle inquires, his tone light, but she's frowning down at the device as she silences it, shaking her head in reply.

"No. I'm going to change," she murmurs, forcing a strained lift of her lips for him and crossing the room to snag a small pile of clothing from the edge of her bed that he can see easily from here, and disappearing into the tiny bathroom.

He hates that she lost what had once been a fantastic apartment only to move into this cramped space with so little privacy, unreliable locks on the door, and a broken heating system. He never stopped wishing she would have remained at the loft longer, until she found the kind of home she deserves; he never would have left this past summer if he was coming home to Kate Beckett every night.

Well, technically, she'd be coming home to him, but he knew that wasn't something she wanted. Though, it could have been, it could have-

His treacherous line of thinking is disrupted by the repeated buzz of a phone on her countertop and Castle rises this time with Sergio still propped against him, crosses the distance in two long strides to peer at the face of the device, grimacing at the photo of Josh smiling back at him.

Sergio bats at the thing when Rick sets him on the counter and he knows it's only because the light and sound has the cat intrigued, know it's childish of him, but he finds satisfaction in the disapproving slap of Sergio's paw to Josh's grin.

"Beckett," he calls as the phone silences, glaring back at him with the notification of two missed calls from her boyfriend. "Phone's ringing again."

"Ignore it," she calls back and he finds sick satisfaction in that too.

"It was Doctor Motorcycle boy," he mutters to Sergio, plucking the kitten from the surface, letting the tiny claws penetrate his shirt to pierce his skin when he tries to climb Rick's chest. "I'm sure he's a good guy – actually, he saves lives for a living, so that's automatic greatness unfortunately, but he's not…" Me, he refrains from confessing to the cat like some selfish, lovesick idiot. "As long as he makes Beckett happy," he compromises on a sigh, venturing back into the kitchen, snagging the canned kitten food they had picked up for Sergio on the way to her apartment. "But I could make her happy. Well, I'd like to think I could, that I can."

Sergio descends from his arm to perch upon the edge of the kitchen sink, watching Castle fiddle with the top of the can and fish a spoon from Beckett's silverware drawer.

"You really did get lucky, you know," he muses, stirring the food, softening it to a near liquid texture. "Which is ironic considering the mythology that you inherited, but finding Detective Beckett is going to be the best thing that ever happened to you, trust me."

Kate lingers just outside the bathroom, her head resting against the thin slab of wall that hides her from sight, from the kitchen, where Castle was running his mouth to the cat, pouting over Josh and praising her, talking about how he could make her happy. As if he doesn't already.

How she's the best thing that had ever happened to him.

To Sergio, the cat, not – not Castle. He wouldn't… no way could she ever hold that title in his life, no way could she ever deserve it.

She counts to thirty before she finally emerges, strolls into the quaint kitchen area to find Castle coaxing the kitten to consume the morsel of wet food on the spoon he presents to him. And unsurprisingly, the cat trusts him, nibbles slowly at first before devouring the proffered food with long-harbored hunger, eventually following the direction of the empty spoon Castle holds to the still full can of cat food on her kitchen counter.

"He must have been starving," Kate assesses softly so not to startle either of them, and Castle glances back over his shoulder, shoots her a proud, crooked smile.

"Yeah, I'm shocked it took us this long to convince him to eat," he murmurs, brushing two fingers down the cat's back before stepping back, allowing the kitten the chance to eat in peace. "It wouldn't be such a bad thing if he stuck around, you know?"

The corner of her mouth quirks. "From convincing me that he was a sign of certain death to suggesting I keep him? Make up your mind, Castle."

He huffs a laugh and brushes past her to plop down onto her couch again. "There's a slim chance I misjudged him. He could be the single exception to the superstitions."

"A slim chance?" she echoes, but Castle narrows his gaze on her.

"The night is still young."

Kate rolls her eyes, checks over her shoulder to see Sergio still content and dining on her counter (that'd be a habit she would have to break quickly), and follows Castle's footsteps to the sofa, snagging her laptop from the coffee table before she takes a seat.

"Ooh, Detective Beckett, are we going to watch a scary movie in honor of Halloween?"

His giddiness is ridiculous but sincere, so much so that she can't help sighing out in defeat, logging into her Netflix account while Castle bubbles with excitement beside her.

It's dark in her apartment, the glow of the laptop in front of them the only source of illumination, and he has a hard time paying attention to the horror film playing on the screen, distracted by the flickers of light that play along her face while she watches halfheartedly. Her eyes in slits and her fingers treading through the fur along Sergio's back, she's listing towards him more with every passing minute, shifting on her side to curl her legs beneath her, drawing the blanket up to her chin as she gets comfortable.

"Sure you don't want to go to sleep?" Castle murmurs, reaching across to touch her knee, but Beckett shakes her head, blinks a few times and focuses her attention on the screen, resumes her gentle combing through Sergio's fur when the kitten stretches between them – half of his body draped across Kate's thigh, his head pillowed by Rick's. "I can leave if you want to head to bed, I know you've had a long-"

"Castle, I'm fine," she argues on a mutter. "It's only nine o'clock and I'm just a little drowsy."

"Uh huh," he chuckles, earning an elbow to his ribs for it, but she reaches for him a moment later, steals a few of the M&M's mixed with popcorn in the bowl on his lap.

"See?" she hums around the chocolate in her mouth. "Awake and enjoying the perks of the holiday."

Castle grins back at her for that, delighted with this soft but wry version of her, this Kate driven side to Beckett that he often only catches glimpses of at the precinct or in the field, enjoying the privilege of sitting on her couch with her guard down and a dozing kitten between them while a Halloween classic plays on the small screen atop her table.

"Thanks for letting me stay," he says casually, risks unraveling it all, but Beckett takes it with a shrug, even offers him a subtle spread of her lips that he almost misses in the darkness.

"Did it for Sergio's sake. He obviously likes you," she answers with a shrug, but she's watching him from the corner of her eye, and he covers the urge to kiss her with a pleased smile.

"That's the first time you've called him by his name," he points out and she groans in annoyance, has the cat twitching in his sleep at the sound before stilling once more. "Admit it, Beckett. You like his name."

"I've accepted that it's not horrible," she mumbles, but he preens with victory nonetheless, laughs when she nudges him in the shoulder for it, tries to concentrate on the movie again.

But the rattle of her front door has them both jerking upright, scaring Sergio into awareness, huddling into Kate's lap for safety. And like a scene from the film playing in front of them, her apartment door swings open to reveal a tall, shadowy figure standing in her doorway.

"What the hell, Kate?" Oh - oh no, he knows that voice and so does Beckett. All too well. The figure strides inside, flicking on the light next to the door. "I've been calling you all… night."

Josh pauses in his rant of annoyance once he's finally able to assess the sight in front of him, of Kate curled up on her couch with Castle mere inches away, a shared blanket draped partially across them both, the startled kitten in Kate's arms.

"What the hell is going on?" he repeats, far more indignant now, his eyes murderous when they land on Castle.

Beckett sighs and eases Sergio from her lap, deposits the kitten into Castle's arms and shoots him an apologetic look as she stands to approach Josh. Rick hears her murmur something to her boyfriend that sounds like 'we need to talk' and watches as Kate proceeds to usher him back out into the hall.

"Uh oh," he whispers to Sergio the second the front door to her apartment clicks shut.

He doesn't stop the movie, not wanting to hear the conversation happening on the other side of the door, but he does place the popcorn on the table, prepares to gather his coat, his shoes, and leave. He'll do his best to bow out before he can ruin the potential for a night in with her boyfriend any more than he already has.

But Rick is already mourning his night with her, the convenient bonding they'd done over the kitten now trembling against his chest, already missing the sound of her amusement in response to his movie commentary and the warmth of Kate Beckett at his side.

He doesn't want to leave; he wants to be the one to make her happy.

Josh storms off down the hall, fighting off another fit of sneezes as he head for the stairs, his head down and his eyes blinking rapidly from the sudden onset of swelling, but the scowl is still carved into his lips. She doesn't blame him for the anger, for the accusations he'd thrown her way, and Kate slumps back against the wall outside her door for a long moment, tries to regain the small pieces of composure that had begun to slip during her conversation with Josh.

She hadn't cheated, but he'd been too upset to believe her, not only because of tonight, but because of previous nights, days, weeks, where she's chosen her job, chosen Castle, over him. And her halfhearted apologies weren't enough for Josh; he deserves better and she would never argue that.

Didn't make hurting him any easier.

Beckett inhales another deep breath, pushes off from the wall to turn back towards the door, only to see a tiny black paw reaching out from beneath it. She huffs, watches the kitten strain to extend his little paw, the thin limb of his arm, out into the hallway carpet.

When she eases the door open, Sergio moves back, stares up at her with those wide eyes, so patient and needy despite his lack of mewing cries, and she bends to scoop the kitten up from the floor, hug the ball of fuzz to her chest. But when she glances towards the couch for Castle, he's already standing, stepping into the shoes he had kicked off before the movie, adjusting his jacket.

"Castle?" His head lifts, a waning smile on his face that strangles something inside her chest. "You're leaving?"

"Yeah, yeah, of course," he tells her, like a reassurance, like he's an inconvenience she's ready to be rid of. "I hope Josh didn't get the wrong idea about what I was doing here tonight. Not that I'm implying he has any reason to think that, just… you know."

She nods, dumbly, but then her head is shaking, an ache through her skull beginning to build. "Josh and I just broke up."

Rick goes still, a compelling mixture of anguish and relief blending through his eyes. "Oh, Kate, I'm – I really hope it's not because I was here tonight. I can go talk to him, explain everything-"

"It wasn't because of tonight, Castle," she promises him, closing her front door behind her and returning to the small area she considers a living room. "It was… other things. Inevitable, really."

"I'm sorry," he blurts, but Kate raises a hand to stop the apologies before they can begin.

"Never would have worked out anyway," she muses, scratching between Sergio's ears. "Josh is allergic to cats."

A startled laugh breaches Castle's lips, spreads to hers, and she hands him the kitten when Sergio stretches for him, already close enough to pounce into Castle's arms.

"You unfortunately weren't completely unlucky tonight after all, buddy," he murmurs to the kitten, allowing Sergio to curl in the crook of his arm before returning his attention to Kate. "Not to celebrate your breakup in any way, but this does make the idea of co-parenting the cat with you a little less awkward."

She chokes on a laugh of her own and scrapes a hand through her hair, bumps his side while she leans past him to silence the movie playing nothing but concluding credits now.

"Who says I want to co-parent the cat with you?" she challenges with an arch of her brow, but Castle merely grins back at her, charming and crooked and reawakening the ever-present urge to kiss him.

Not yet, but soon.

Very soon.

"Come on, Beckett. He loves me and well, you're just stuck with me," he shrugs and she scoffs, but doesn't deny that.

"Fine," she mutters, scratching her nails through Sergio's fur, grinning as he purrs into Castle's chest, and bypassing him to reclaim her spot on the sofa. "It's still early, want to watch another horror movie?"

He practically beams at her for the request.

"Forget what I said about you before," Castle whispers to the dozing kitten while he crosses the room to turn off the lights, bathing them in the comfortable glow of the laptop screen once more and spilling another secret smile onto her lips that she does her best to hide before he comes back to her. "You're the opposite of bad luck."

Castle finds new excuses to show up at her apartment within the following weeks, even after he's helped move her into a new place, claiming that his reoccurring presence is "necessary for Sergio's upbringing". And she doesn't fight it, because she's growing used to his consistent presence outside of the precinct, to having dinners with him in her kitchen and lounging on her couch with him and the cat for an hour or so afterwards.

When he shows up on her birthday after work with an overly expensive cupcake and a tiny, birthday themed sweater for Sergio to wear, she arches on her toes in the doorway, smears a kiss to the corner of his mouth, doesn't stop him when he cups her cheek in his palm, holds her there.

She welcomes the seal of his lips, the tentative stroke of his tongue that has a moan rising in her throat; he drops the cupcake, bands his arms around her waist, and avoids the inevitable fight with Sergio over that stupid sweater.

"Stay," she murmurs, her fingers hooking in his collar to guide him backwards with her, towards the path that leads to her bedroom.

Castle nods, catches her bottom lip between his teeth and sucks, has her gasping and burying her fingers in his hair to hold on.

"Not – not in front of the cat," she pants, hastening their stumble to her room, glancing over his shoulder to see Sergio content and curled on her couch, oblivious to the unexciting development in his owners' relationship.

Rick laughs against her cheek, low and husky, and she pushes him up against the door to her bedroom once its finally closed.

"Luckiest cat ever."