Chapter 1

"You want to do what?" Petra's parents gasped.

"I want to take a year out. Travel. Be independent."

Castle stared. Beckett smiled, slowly. She'd had an inkling that this was coming – not least because Petra had been more and more impatient with David recently.

"But what about college?"

"Dad, I got practically a perfect SAT score. They'll wait for me. You know they will."

"But you're not even eighteen."

"So? I'm perfectly capable of travelling alone." Petra's smile had more menace and teeth than a human ought to have had. Of course, that was because she wasn't entirely human.

"I think it's an excellent idea," Beckett said briskly. Everyone's jaw dropped.

"Beckett!" Castle wailed.

"You do?" Petra gasped.

Beckett certainly did. She'd had nothing but attitude from Petra since the day she turned ten, though since Beckett had multiple doctorates in attitude herself, from her teenage days, they hadn't had much of an effect. The arguments had been spectacular, but Beckett had won, every time. Castle, and swiftly David, had hidden. Or gone out. Or gone out and then hidden.

"I do. The only stipulation is that you don't get caught, and you either call home once a week or e-mail."

"No-one uses e-mail." Her tone said dumb parents.

"You will. Or you'll give me your newest Instagram password."

"Mom!"

"I can hack it, you know."

Castle blinked. He was sure Beckett couldn't – but on reflection, Ryan and Tori the tech certainly could. Petra's blush was something into which he really didn't want to inquire.

"Where were you thinking of going?"

"Uh…South America. Or India, or Indonesia."

Beckett waited. When it was clear there was no more to come, she tapped her fingers lightly on the counter. "You have a month to come up with a plan – including an itinerary, costs, flights, and duration. Maximum, three to six months. Not a whole year, and you have to prepare and submit your college applications before you go. We'll pay the airfares – economy only. Everything else is down to you. I expect to see a plan for not being discovered, too."

Petra stared at her mother, disconcertingly physically similar in face, figure and expression. "I don't want you following me. And I'm not taking David."

"We won't," Beckett said over Castle's distressed noises. "And no, David won't be going with you. If David wants to travel, he'll have to do it without you. He hasn't finished high school yet." David would almost certainly not want to travel, when he finished high school next year. He was as smart as Petra, but, catlike, he was comparatively indolent. Petra had powered through high school, and had been accelerated by a year – which hadn't stopped her taking a clutch of AP classes – where David was quite content to take the full four years, enjoying all the social life and popularity that a good looking, tall, broad teen could have. David played football, extremely well, having the decidedly unnatural advantages of his other form even when human, and was generally sure to have a crowd of pretty girls around him when he came off the gridiron. Some of them came home. Some of them, after meeting Petra, even came twice.

Petra could have been popular. If, that had been, she'd ever bothered to try. If her class wanted something organised, Petra was top of the list. If they wanted softness and sympathy, they avoided her. She had two or three very close friends – though none of them knew her secret – and that was just fine by her. On the rare occasions that Petra talked to her mother (to Castle's chagrin, she never seemed to have heart to hearts with him), the dominant flavour of conversation was how dumb and childish everyone else was, and how they should all stop the bitching and squealing and grow up.

Beckett normally declined to make any comment, though she frequently thought that Petra could do to re-read the story of the mote and the beam in one's eye.

"You mean it?"

"Have I ever said anything to you that I don't mean?"

"You haven't. Dad, though…"

"Hey!"

"Yes, I mean it. I think it'll be good for you. When you come back, you can go to college. Or get a job."

Petra stared at her mother, who looked blandly back at her. Suddenly, she rushed forward and hugged her. "Thanks, Mom." She stepped back. "Can I go to Central Park tonight and practice? I'll need to catch my own food wherever I go."

"We'll all go."

"But I wanna go alone! You won't be there where I am!"

"But I am here. We'll spread out, but you are not going to Central Park on your own."

The complete illogicality of forbidding Petra to go to Central Park alone but allowing her to take a gap period and travel the world alone was not lost on Beckett, but she could see Castle barely holding in objections and upset that his adored younger daughter wanted to go off without them. Alexis had never actually done that, and even now that she was in her late thirties, with a home and family of her own, she still saw her father regularly.

Petra was a much more normal teen, rebellious and sulky, but Castle had no experience of that – although he'd learned fast, as had Beckett. Parenting two shape-changing teens was very much a joint effort, but as the terrible twosome had grown up, Petra had gravitated to Beckett and David to Castle for difficult issues. Beckett had approved. She had no desire to deal with male puberty, and Castle certainly didn't want another go-around of female puberty. She still thought that Castle had gotten the easier end of the stick, though. David was laid-back and easy-going. Petra…wasn't.

Five minutes later, Petra had disappeared upstairs, no doubt to start her planning. David had, much earlier, claimed a study group, which, Beckett felt, likely involved a close study of some pretty girl's uvula. He'd be home for dinner. She didn't think too much about that – but had checked that Castle had had appropriate discussions about safety.

Oh. Oh, ugh. That was a discussion that she would need to have with Petra in short order. High school would finish in less than a month – and Petra would need to see an ob-gyn. Specifically, she would need to see Dr Maine, who was aware of all of the, um, unusual issues around the Castle twins. Even though Dr Maine was now well into her sixties, she remained the best doctor of whom Beckett knew.

No time like the present, Beckett supposed – and then caught a glimpse of Castle's face. He looked devastated.

"What's wrong, babe?" She hugged him. "Are you worried about her?"

"Yes, but… Doesn't she love us?" he burst out. "Alexis never wanted to go away for months on end all on her own without even calling, and David doesn't. What did we do wrong with Petra?"

"Nothing," Beckett said briskly. "You're being silly. Understandably, I guess, but silly. Petra isn't Alexis, and David isn't Petra – thankfully," she added. "You and Alexis had a totally different relationship because for most of her childhood it was just you two. You didn't even meet me till she was almost fifteen. And Alexis is a totally different personality. Petra's much more independent." She smiled. "She's just like I was, and I survived adolescence. Even my dad survived it. Petra's got advantages I didn't have till I was nineteen." Castle's doleful look didn't lift. "Look, babe. Wouldn't you rather she told us she wanted to go and we have her plan it, rather than her just running off? She might, you know. She's just that stubborn."

"I guess," he said miserably.

"This isn't about you or me or even David. This is Petra growing up."

"She shouldn't," he pouted.

"I like this stage better than diapers and tantrums," Beckett pointed out tartly. "Even with the attitude, it's better than the tantrums." She dropped a kiss on his still-not-greying hair. "Now lighten up. When it gets dark, we'll all go out to Central Park and play chase."

"That's no fun with the twins around either," Castle sulked.

"And then we'll come home," Beckett murmured, and mischievously squeezed his ass. "Now, come and get a glass of wine."

"Okay." He hugged her back, leaning on her just for a moment.

Beckett had thought that it was toddlers who experienced separation anxiety, but it seemed like Castle was in for a bout of it too. "You could always talk to Dad," she suddenly said. "Ask him how he felt when I was going off to Stanford."

"Yeah. Will he remember?"

"Oh, I think so," Beckett said firmly. "He might be a bit frail, but his memory's just fine."

"Maybe I will. I'll give him a call after dinner."

"Yeah. I need to have a talk with Petra."

"Oh?"

"If she's going to go travelling, then there are some, um, practicalities that we need to take care of." Beckett coloured up.

Castle's ears went pink. "I don't want to know," he said.

"Nor did I, till I thought of it," Beckett agreed. "I think I need to have a glass of wine before that discussion – or several."

Castle opened a bottle, poured, and half their respective glasses disappeared in two synchronised gulps.

"Did David say he was going to be back for dinner?" Castle asked.

"Only if he can't talk whichever pretty girl it is this week into dinner elsewhere," Beckett said cynically. "He's just like you were."

"Oh, God," Castle sighed. "I really hope not."

"Fate's revenge on you." Beckett smirked. "Now you know how your mother felt when you were seventeen."

"I think I know how your parents felt too," Castle smirked back, and then his face dropped again. "But why does she have to go so far away? What's wrong with the States?"

"Says the man who's been around the world four times over on book tours. Anyway, I went off to Kiev for a semester."

"Couldn't she be just a little less like you occasionally?" He caught Beckett's eye. "You're amazing – but you're you. Petra's seventeen, and it's really disconcerting to have two of you when there should only be one."

The dreaded left eyebrow rose. "Keep digging, Castle. You're going to reach Australia shortly."

"I mean…" He trailed off. "I don't know what I mean."

"That makes two of us," Beckett snarked.

"And you agreed with her," Castle carried on, plaintively.

Beckett changed tack. "Do you remember when they were tiny?"

"It's not easy to forget. I still have some scars – literally."

She ignored that. "We agreed that they had to go to day care so that they wouldn't always just be with us. They couldn't stay at home for ever. This is just the same."

"But…but she's in such a hurry to leave. Accelerated, AP classes – she's got herself a year ahead of David, even. Aren't twins supposed to stick together?"

"It's not like when they were tiny and wouldn't be parted – even if they fought non-stop when they were together."

"Yeah. But… but aren't you worried?"

"Yes," Beckett admitted. "But she has to spread her wings sometime, and it might as well be now. It's not that much fun being at college a year early – socially – and she's already got enough social issues without adding that one."

"What, like the inability to suffer fools at all, let alone gladly?"

"Yeah. And the teeth, claws and changing."

"Can't we follow her?"

"No." From Beckett, that carried the weight of a tablet of stone. "We have to let her." Her face fell. "I don't wanna either." She curled into Castle's side, and poured more wine. "Go talk to my dad. Maybe that'll help. And we'll all go out to Central Park after dinner and murder squirrels, and you know that always makes everything better."

Castle managed a snicker, though it didn't carry his usual cheer. "Okay," he said, but pouted. "I don't have to like it, though."

"No, but you do have to suck it up. Just like I have to go and have an embarrassing discussion with Petra, right now." Beckett had a thought. "Don't say anything to David till we're all having dinner. I think it might need both of us to keep that calm."

"Okay. First, though" – he tugged her round to kiss her.

They pulled apart just as the front door opened. David bounced in, full of good cheer and a satisfied air that made both his parents extremely suspicious of his so-called study group. "What's for dinner?" he asked hopefully.

"I don't know yet," Castle said. "Come help me choose. Mom's going to talk to Petra about school."

"You know she's valedictorian," David said casually.

"What?" came from both parents, swiftly followed by, "Petra!"

"What?" grumped down the stairs, not followed by Petra.

"Come down here."

"What is it?"

"Are you valedictorian?"

Petra turned a Beckett-worthy glare on David. "Did you tell them? Why?" she screeched. "That was my news and I was going to tell them" –

"You were not. You said you didn't care and you weren't going to make a fuss about it" –

"You said what?" the parents gasped.

"Grandad told me that you didn't tell them, Mom, so you don't have a leg to stand on. They only found out when they got a call from Stuyvesant the day before."

Beckett blushed. Along with skipping prom, she'd tried to hide that one. She'd been roasted by her mom.

"Really?" Castle said, instantly distracted, as Petra had probably intended. Unfortunately for Petra, Beckett was not distracted.

"That was me. And this is me too, and we will be attending – and we were going to anyway, since it's your graduation, but now we'll call the school in the morning to make sure of it. But while we're all letting cats out of bags" – the whole family groaned – "let's just talk about your year out."

"What?" yelled David. "She gets a year out? Doing what? That's not fair!"

"I'm going travelling. Without you following me around and getting in the way and vetting my boyfriends" –

"I do not" –

"What boyfriends?" Castle gasped.

"Tell you later," Beckett nudged him.

"You knew?"

"Sure I did. Don't worry."

"Don't worry?" he squawked.

"We'll discuss it later." She looked at the twins, who were snarling at each other and seemed likely – dammit! "Change back!" she ordered, in a tone which still meant deep trouble if it were not instantly obeyed. Sulkily, they both did. "Right. David, Petra is going travelling on her own. If you want to do the same when you've graduated high school, you can, on the same terms. We'll pay economy air fares, the rest will be up to you. We have to see a thought out plan and itinerary, including how you are not going to be discovered. We won't follow you." She drew breath. "Petra, we'll discuss your omission of vital information shortly. Right now, we have a different discussion to have, privately. Upstairs, in your room." Petra didn't move. "Now." She went, followed by Beckett.

"Dad?" David tried.

"Nope. You didn't want to be accelerated or put the work in, so you have to wait."

"Uh, that wasn't what I wanted to talk about." David squirmed a little in his seat.

"Girls?"

"No! You told me all that." He blushed. "Uh…can we go into your office?"

"Sure," Castle said, panicking internally.

Upstairs, Beckett had sat down on the stool of Petra's vanity unit, and regarded her difficult daughter with a wry smile.

"I would have told you," Petra eventually muttered.

"In time to attend and sit near the front?" The delicately eviscerating tone made Petra squirm. The raised eyebrow was worse.

"Uh…"

"No, then. Well, we will attend. It's important to us. That discussion is over. I want to talk about something else. Specifically" – she steeled herself – "I want you to go see Dr Maine, as part of your planning."

Petra blinked. "Is that it? I already made an appointment for next week."

Beckett blinked. "You did?"

"Sure I did. I'm not a baby and I'm not stupid. I don't ever want kids."

I thought that once, Beckett thought, but didn't let it slip by a single twitch of an eyelash. "Fine. As long as you've got that covered."

"Yes, Mom. Stop fussing."

"Fine. Then after dinner we'll all go to Central Park, late on, and you can practice catching your own food." Beckett suddenly remembered something. "When you talk to Dr Maine, make sure you get something that isn't affected if you get food poisoning."

"I know" – Petra stopped, and examined her mother's face in a way unpleasantly reminiscent of her mother examining guilty perpetrators – "Personal experience, Mom?"

Beckett bit the bullet. "You two didn't arrive on a stork." She grinned ruefully. "Don't eat squirrels."

"Ewwwww, Mom!"

"You asked."

Petra growled.

"Don't growl at me. Dinner in a little while."

"Okay." Petra's attention was already on her laptop as Beckett exited.

Downstairs, there was no evidence of either of the males. A swift glance showed her the two of them in Castle's office, evidently having a serious discussion. She didn't intrude. She and Castle would swap notes later. If they weren't both fully briefed, bad things happened – usually around the twins trying to deceive them about what the other had said or agreed to. It didn't work, but that hadn't ever stopped them trying. She checked the dinner, set the table, and settled down with her wine and a book until the meal was ready.

David exited the office without comments, and Beckett could see Castle picking up his phone. Her father was into his eighties now, a little frail, and definitely elderly, but his mind worked as sharply as ever it had. He'd help Castle get through the separations.

Unusually, dinner passed off peacefully. Petra was lost in thought, calculations running through her face, and said almost nothing. David looked as laid-back as ever, but Castle was slightly discombobulated, and kept sneaking glances at David. Beckett sipped her wine and stayed quiet, assessing the situation as another variant of their babies being all grown up and spreading their wings – or, given their strange natures, expanding their hunting ranges. It was hard – but it was still a damn sight better than their toddler years. At least now they understood logical argument – and that no matter how hard they argued, their parents were in charge. Seventeen years of absolute reinforcement of that idea and always following through on consequences had rammed that one home.

Dinner over, clearing up done – by everyone, insisted upon by (according to the twins) tyrannical parents – the twins disappeared to their separate rooms. Now, they usually stayed separate, but every so often – at moments of emotional strain – they could be found in cat form, curled together, or one being comforted by the other. When they squabbled, which was still distressingly frequent, they had a nasty tendency to convert to panthers, and while David now had considerable bulk on Petra, she was much more vicious. Beckett mused that the two of them were now almost identical-looking to their parents: Petra a slim Siamese; David a Maine Coon, just like she and Castle respectively; and all four of them pure black in all feline forms.

Thank you to all readers and reviewers.

So here we go again into the insanity that is the Caskett Cats. Posting will be Sun/Tue/Thu as usual.