Chapter 1

The day Richard Castle found a stray cat strutting through an alley, uncollared, unchipped, but clearly very expensively pedigreed, was the end of his world as he knew it. He just didn't realise it. Then.

He was quite busy enough. Being a world-class playboy, squiring beautiful women around (well, following Beckett to crime scenes: she was certainly a beautiful woman but squiring might have been a bit of a linguistic stretch), writing best-selling novels and keeping a happy home was commonplace, and when he added launch parties, readings and murders to the mix, there wasn't really time for anything else. It didn't stop him wanting to add one thing more, but Beckett was as impervious to his charm as she had been since he'd apologised after the summer and she'd, begrudgingly, accepted.

He needed to take a sneaky break from the latest reading, to have a short respite from the claustrophobic crowds of fans, to rest his voice and refresh the star personality that he needed to project all evening. So he'd slipped out the back of the bookstore into a quiet, dark alley, leant against the wall, hoped he wouldn't ruin his Hugo Boss suit or worse, his hand-made shoes, and simply shut down for a few moments.

He pondered the difference between his day job, such as it was; and the ins and outs of the regimented life of the cops he followed around. Strict shifts – although they all seemed to do inordinate amounts of overtime when they had a live case – strict hierarchy. And, always at the top of the team, the stunning, sexy and still entirely unobtainable Kate Beckett.

He contemplated Beckett with a mixture of lustful enthusiasm and complete unhappiness at her lack of interest in dating him, until he noticed movement at the entrance to the alley. He peered into the gloom, barely making out the motion, until it curled around his legs, close to invisible, and on bending down he discovered it to be a pure ebony cat: not a hint of any colour; moonless, starless midnight black except for its piercing green eyes. He essayed a respectful scratch around its ears, and since it didn't scratch back, petted some more and then picked it up. It settled on to his chest and shoulder, curling into his neck. He stroked it some more, murmuring nonsense to it, and it began to purr contentedly. Castle experienced a sense of considerable pleasure that the cat liked him (so unlike Beckett), and returned the favour in spades by petting it until the purr was continuous.

Of course, right about the time he discovered that this beautiful creature was uncollared, he was also sought and summoned back to his reading: recess over. He gently put the animal down, and, ridiculously, felt the need to tell it what he was doing. He bade it farewell, but the cat followed him in, and sat, very cat-like, right at the front of the audience, to stare at him for the first few moments of the resumed reading. Then it washed a paw, and on completing its ablutions, regarded him curiously, flicked its tail dismissively and prowled proudly away. He lost sight of it immediately.

Around halfway through the second half of his reading, Castle looked up from his extract to discover Beckett, garbed in her normal, formal shirt and tailored pants, watching from the side of the room. He was rather pleased to see her. He knew she was a fan.

"Beckett!" He bounced up to her, high on success and applause. "Did you enjoy it?"

Beckett quirked an eyebrow in her patented sardonic way. "I've heard worse," she drawled, and just as Castle started to pout carried on, "but I'd have been happier if I'd made the beginning of the night."

"Oooh, compliments. I knew you liked me." He stopped at her put-upon eye-roll. "Why'd you miss the beginning?"

"Busy," she said shortly.

"New case?"

"No, admin. Had some stuff to take care of."

"Oh. Never mind, you got here." He looked around, trying to spot the cat again. He didn't want it to be frightened by all the people, or worse, hurt.

"Castle, why are you looking around all the time? I know you have the attention span of a hyperactive flea, but" –

"There was this cat…"

"Cat?"

"I sneaked out back for a break," he explained, "and the cat slinked into the alley. It was gorgeous: coal black, green eyes, very elegant. It liked me."

"Something has to," Beckett snarked. Castle ignored that.

"Strange, though, it didn't have a collar. It looked far too elegant for someone not to own it."

"Maybe it was chipped," Beckett pointed out. "Less obvious, and more permanent. What did you do with it?"

"I brought it in, and it listened" –

Beckett sniggered at his fancy. "A cat listened to your reading?" –

"It did. Paid more attention than most of the audience, too." He frowned at her. "But then it wandered off. I don't know where it went. I hope it's okay."

"Can't say I saw any cat when I came in," Beckett said thoughtfully. "Nope. Sorry, Castle. I'm sure it'll be on its way home by now."

Castle was disappointed by that idea, and showed it. "You think?" he asked.

"Yeah. Cats are pretty independent."

"Do you like cats?"

"Yeah, but I've never had one. We never had pets when I was young, and the job's too random to have a pet now. It wouldn't be fair."

"We never had pets either, but I've always liked cats. Plenty of cats round theatres."

"Why'd you never get one once you had the loft?"

"Alexis was small, and then Mother moved in, and she was quite enough to manage. I guess I just never thought of getting a kitten."

An enthusiastic fan wandered up at that moment. "Mr Castle, I really love your books," she gushed. "Could you autograph this one, please?"

"See you tomorrow, Castle."

"Till tomorrow," he returned automatically, and turned to the fan, who was followed by streams of others, all wanting books signed and a few personalised words so that they could say they'd met their idol. As the room began to empty, late on in the evening, Castle became aware that the cat had returned. It was perched on a chair, head over its front paws in a classical Sphinx-like position, watching him. He couldn't resist going back to it, sitting next to it, gently fondling its ears and then stroking all the way down its back. The cat purred loudly and then leapt into his lap, clearly demanding more petting.

"Okay," he stated to the cat. "I don't know who you ought to be with, but unless someone here owns you" – oddly, the cat extended its claws and growled – "how about coming home with me?" She – Castle had finally worked out that this cat was female – miaowed in approval, and climbed over his chest to pillow herself on his shoulder. Clearly she was well used to being carried around.

All the way home she stayed curled on his lap, perfectly well-behaved, not in any way bothered by the cab or the Manhattan bustle. Castle concluded that whoever's cat she had once been, she had had a very pampered life. Her fur was smooth and flawless under his stroking fingers, her eyes emerald-bright as she stared into the city night, her flexible torso slim and elegant, and even her claws were neat.

The family were long abed when Castle came home, bearing his new acquaintance.

"They'll love you," he told her. "You're beautiful."

He fussed around for a moment or two, pouring some milk into a bowl and taking it through to his study – he was always fired up to write after a reading: inspiration arriving on the high-tide of adrenaline – and making himself a mug of coffee. The quizzical look the cat gave him when he went to put the bowl on the floor made him abruptly alter his movement to place it on the desk. She jumped up after it and lapped happily, the small short movements of her tongue disposing of a reasonable quantity quite quickly. Once satisfied, she positioned herself on his desk with the grace and power of Bast, the epitome of felinity as shown in art from the earliest Egyptian hieroglyphs and frescoes. He stretched out to stroke her, completely incapable of resisting her stare.

A few minutes into both creativity and coffee, Castle noticed that the cat was watching his screen. If he hadn't known better – he was sure that cats could not learn to read – he would have sworn that she was reading his words. When he stopped, she met his confused gaze, mewed, and then padded over to his coffee mug and sniffed at it. He had the most peculiar impression that his lovely new companion liked it, but he was also sure that most cats – all cats? – didn't drink coffee. Beckett drank coffee, of course. Beckett drank enough coffee to float an aircraft carrier. He wondered why the cat reminded him of Beckett. It was probably the cool, everything-on-my-terms attitude. Come to think of it, Beckett was very feline in so many ways. Unfortunately, his chances of having Beckett curled in his lap or purring at him were approximately zero. He couldn't be sure that she wouldn't shoot him, or break his leg, if he so much as stopped her falling over. Not that she fell over, either. How she managed to balance on those heels… Anyway. The cat may have reminded him of Beckett but she wasn't Beckett. She was much more affectionate.

"I'd better find a name for you," he decided. "I can't call you she all the time, or cat." She miaowed, and fixed him with a hard stare. "Something appropriate. Ebony?" She didn't look impressed. It bore a remarkable resemblance to Beckett's expression every time he came up with a way-out theory. "Obsidian?" Some warmth. "I know, Onyx. A black precious stone. Okay, so you're not a stone, but your fur's gleaming just like the polished variety." She butted her head against his hand and purred. "Onyx it shall be, then." Obedient to her clear desire, he stroked her head and back, and then she jumped for his shoulder.

With a little experimentation, Castle discovered that he could type despite Onyx being attached to his shoulder, and did so, encouraged by the gentle purring vibrating against his neck. She was delightfully soft and warm, and since he had been short of any other form of soft, warm, female companionship for some time – ever since he'd really got into the Twelfth – he lavished petting on her. The next day, he decided, he'd take her to the vet and make sure she had had all her shots. Then reality descended. Before he could do that, he really ought to make sure she hadn't been reported missing. He wasn't a thief. The vet would know if she had a chip, though. The thought that she might be somebody else's pet, and that therefore he might have to give her back, made him gloomy, and inspiration began to fade.

"C'mon, Onyx. It's bedtime. Tomorrow, we'd better get you checked over. If you are someone's, they'll be missing you." He watched her prowl across the floor to his bed. "If you're not, then you can stay here." She leapt on to the bed, looking around the room. He had that same odd feeling of familiarity, and pinned it to the way Beckett looked around a crime scene: how she assessed every inch of the site and the corpse. Under the pressure of the cat's stare he shut the bathroom door and conducted his night-time ablutions in privacy. When he returned, the cat appeared to assess every inch of him, then betook herself to the bathroom, much to Castle's astonishment, butted the door almost closed, and a few moments later returned.

"You use the bathroom?" He resolved to get a litter box. If he was allowed to keep this beautiful cat. "Wow." She regarded him with a don't be dumb glare that, if it had only included an eye-roll, would have been exactly the same as the one Beckett bestowed on him a dozen times daily. His mind skittered off as he snuggled down. "I should introduce you to Beckett." The cat looked questioningly at him. "She's my partner. Well, she pretends she isn't, but she is. We solve murders together, and even though she growls at me and rolls her eyes she listens. She'd like you. She's beautiful, too." Onyx purred softly. "She said she liked cats. The only thing is, that the pair of you together would terrify everyone. For a cat and a human, you share a lot of the same expressions." She made a noise of disbelieving disgust. "Okay, everyone knows that cats are infinitely superior to humans." The purr returned.

Onyx curled herself up on the opposite pillow while Castle tucked himself in comfortably. Once he was installed, she placed herself neatly within the junction of his neck and shoulder, and closed her eyes. Castle emitted a contented little noise, and shortly fell into sleep. Strangely, all his dreams were of Beckett. Not that that was in any way unusual: he dreamt of Beckett most nights, but these dreams were less X-rated and more affectionate: he dreamed that she was tucked into his arms, the scent of her hair in his nostrils.

When he woke, Onyx was missing. The only evidence that she had been there was a dent in the pillow and two or three coal-black hairs. He was bitterly disappointed.

"I don't understand where she could have gone," he complained to Beckett. "She couldn't have got out."

"Sure you didn't just imagine it? You imagine everything else."

"No. I have the cat hair to prove it." Castle was determined. "I'm going to check if there are any missing cats. She was so distinctive – if she was lost, it would have been reported."

"Go ahead. I'll just get on with the trivial stuff like solving murders. Maybe Ryan'll put out an APB for you."

"You mock me," he grumped. "At least Onyx liked me. She even slept on my bed."

"Did she? You must have some good qualities, then. To a cat."

"I'm sure you'd appreciate my good qualities in bed, Detective." Beckett made a noise of disbelieving disgust. "Onyx sounded like that too. You should definitely meet her."

"Meet her? Are you seriously suggesting that I should be formally introduced to a cat?"

"Yep," Castle said happily. "You'd get on like a house on fire. Of course, you'd need to be nicer to me. Onyx likes me. She might not take it well if you threatened me."

Beckett looked at him with a familiar mixture of irritation and confusion. "Or we might gang up on you. Which would make far more sense. Anyway, since you can't find this mysterious cat, how about you let me get on with the day job?"

"I'll find her," Castle promised. "She was beautifully pettable and affectionate. She can have a home with me." He smirked evilly. "Of course, it would mean you'd need to share me."

"I wasn't aware I wanted to have any of you."

Castle gave her a scorching look from toes to head, lingering on her form. "Really?" he husked. Beckett acquired a line of high colour along her sharp cheekbones. "Anyway. I'm going to find Onyx and if she doesn't have an owner I'll keep her."

"Knock yourself out, Castle."

Castle spent the rest of the morning making a series of enquiries and, just in case Onyx showed up again, talking to a vet he knew who would give him a late-night appointment. He put the phone down and sighed.

"No luck?" Beckett asked, almost sympathetically.

"Nope. No-one's reported a pure black Siamese missing, but no-one's found one either."

"You're really upset," she said, surprised.

"Yeah. She was gorgeous."

"I didn't realise you were so enamoured already."

"Yeah," Castle admitted. "I guess I fell in love with her straight away."

Beckett raised an eyebrow. "I thought you only fell in lust straight away."

Castle failed to reply for a minute. Running through his head was I fell in love with you, didn't I? Not that that had been straight away. It had taken at least two months, right about the point he had first saved her life. But if he couldn't have Beckett, he could at least have Onyx, who was proving to be affectionate and lovable. He would have rather had both, but Beckett seemed to be as unattainable as ever.

"I can't explain it," he eventually said. Beckett didn't press him. She was, in fact, looking rather confused, which swiftly changed to sympathy.

"Why don't you get yourself a coffee and then concentrate on this nice messy murder for a while," she suggested. "Then you can go home and see if your cat turns up. She's probably sleeping in your linen closet by now, on the towels."

"Hope so," he said miserably.

"I'm sure she will. Better get some treats for her, though. That'll coax her out of her hiding place."

"Mm." He made an effort to cheer up. "What sort of treats would coax you out, Beckett? Wine? Chocolate?"

She rolled her eyes. "Bribing a cop is an offence."

"Who said anything about bribery? I'm not asking for illegal favours in return." His smile was salacious. "Just trying to make sure that when you come and meet my cat you'll be satisfied with every aspect of the evening."

She groaned, and then turned to her work. Castle continued to search through missing cat stories, becoming more unhappy with every tale of traffic accidents or fatal encounters with stray dogs. He eventually took his moping self home, but on the way stopped off to purchase a large packet of top-quality cat treats. It might work, he supposed, but a full scale search of the loft failed to find a single hint of felinity.

Around seven p.m. the doorman calls up. "Mr Castle, you know you said if I spotted a black cat…?"

"You found her?"

"Sure. She was sitting right here on the doorstep, so I let her in."

He practically ran to the elevator.

"Onyx, you naughty cat. Where'd you go off to? I was worried about you." He hoisted her on to her already-accustomed place on his shoulder and she purred into his ear as she settled. "I looked all over for you. I still don't get how you got out."

He took her upstairs and fed her a small handful of treats, watching as she neatly nibbled at them and drank some water. He'd done a little more research, and found that too much milk was bad for her stomach.

"Now, let's take you to the vet," he said. "I need to know if you're chipped or not."

From the look Onyx gave him, she didn't want to go to the vet. However, she consented to be picked up and snuggled against him, and didn't complain when he hailed a cab.

Thank you to readers and reviewers.

This is gentle, silly fluff in six chapters, for the Halloween Bash. Posting daily, as it's complete.

Inspiration came from InkyCoffee's cat, which featured in the CastleFicStreamCon - check it out on Twitter/Tumblr or via Griever11, to whom all thanks are due.

For those of you of a Beckett-ly cynical nature, I had a friend some years ago whose two Siamese cats did indeed use a normal human toilet.

For those of you reading What's in a Name, I really, really appreciate all your support. Although my eye is recovering well, Name is complicated (as if you all didn't know that!) and requires a lot of cross-referencing/checking back, which I am currently finding very difficult as I can't put it side by side (too small). I certainly haven't forgotten it, and indeed I have been able to continue it, but until I'm happy that I can proof read it properly I can't inflict it upon you. Maybe this will make up for the lack.