A/N: Man, this was a fun little break. Let's do it again sometime, shall we? … Thanks for your patience, guys.

…………………

Chapter 2

…………………

"All you mental armor drags me down…"

…………………

Derek,

I'm glad you were able to work things out with Kendra; it's for the best, isn't it? We had lunch on Wednesday and all she could talk about was how much she missed you… please take care of her.

I know I threw myself in the middle of something that was entirely between you and your wife; I won't do it again. How you choose to tell her, or if you do, I'll leave in your hands.

I'm sorry.

- Casey

…………………

She'd written him a letter, old-fashioned, and had a messenger service deliver it to him on set.

Derek was surprised; he'd expected an email. Something curt and business-like with emotionless congratulations on his happy reunion and a vaguely-worded, but meaning-heavy, sentence alluding to certain "mistakes" that would best be forgotten for the sake of preserving "all" relationships.

Sometimes he felt like he knew her completely, inside out, to the point where he could anticipate her every move. Then she'd do something unexpected and he'd be forced to re-examine all the things about her he'd mentally catalogued - the work of years of study.

When he considered it, though, it shouldn't have been unexpected at all. Of course Casey would feel like what had happened between them needed something more… tangible than just words thrown into cyber space. A letter would seem fitting to her, the sentimental type, who'd find more feeling present in the stroke of a pen than the click of a keyboard. It was everything that was sincere, and brave, and romantic about her.

And effective. Derek could definitely see, in the shaky quality of her penmanship, how painful it had been for her to write. The deep wistfulness beside the bittersweet warmth of her words.

He didn't know how long it took for her to work through all the anger and the impulse to blame him (she always did if she could), but he had suspected she'd probably come around to blaming herself eventually. At the very least, just as the result of her condescending approach to the idea of his basic morality (that he would do something unethical was a given, but she should naturally be above such things). But also because she was not the terrible person he supposed she felt herself, at present, to be. This was her again extending the proverbial olive branch with vulnerable hands to be the first to step towards acceptance and forgiveness. She was so imperfect in spite of herself, deeply flawed, but she redeemed herself over and over. Stubbornly.

So he read her letter, twice, before tucking it away in his pocket absentmindedly. He felt how upsetting it would be for her to think he'd treated it casually after such an effort. And he was able to be kind to her when she wasn't around to witness it.

He was also, apparently, capable of a lot more towards her than even he had suspected of himself. Sex with his stepsister. Frantic, rushed, biting, tearing, leave-the-clothes-on, Nine Inch Nails Closer sex. 'My whole existence is flawed; you get me closer to God.' He wanted to regret it, and he did in a way that wasn't really remorseful at all. The act itself, the thing he should feel sorry for, he didn't; his regret was saved for the impossibility of it ever happening again.

He'd already decided not to tell Kendra. He knew keeping something of that magnitude from her was ostensibly wrong, he did, and he felt like an asshole. But, the fact was that he simply could not actually bring himself to say it out loud. For a million reasons that were all selfish, and humiliating, and wrapped up in Casey and everything about them that was just theirs for all its fucking insanity. He didn't want their subtext to exist for other people, wanted to keep it locked between them, an unspoken substitute for the reality they couldn't feasibly have.

Thursday night, he'd come home to find his wife seated on the living room floor, wine glass in one hand, their wedding photo in the other. She'd talked of their history, the friendship they'd formed after their first big break-up, mutually sustained by just how alike they were. Their lives seemed so parallel, and if they were headed in the same direction, they'd always be beside one another.

Derek had been poised to tell her that he'd suspected all along that he wouldn't be great at the whole marriage thing. But she'd beat him to it, said it of herself and added that they'd just have to learn together, wouldn't they? She didn't want to lose him, not without at least fighting for him – them – first. They were only six months in to the whole arrangement; it couldn't be the end!

All she wanted was a clean slate, forget Kerry, and cold feet, and whatever else. Could they start fresh?

Derek was used to getting what he wanted. The Universe had always been kind to his whims and desires, and what it failed to give him, he won for himself with his easy charm. The Venturi Charm, his dad called it, but what George wielded with adorable awkwardness, and Edwin with winking smarminess, was a true force in Derek's capable hands.

And yet, for too many reasons to list, he very obviously couldn't "have" Casey. She should have stayed the 'what if' she had seemed destined to always be. His wife was the one he was allowed to – supposed to – love.

So, he gave her the clean slate she'd asked for, sweeping every mark and blemish aside, leaving stark whiteness behind like a newly painted wall between them. Parallel lines do not intersect.

…………………

By Sunday, Derek was ready to chalk the past week up to an aberrant fluke.

His life had changed drastically in a matter of days before very abruptly snapping back to what he'd come to know as normal. There were a few outbursts, a few emotional scenes (the type he was loathe to be part of), and then… Saturday. Waking up with his wife beside him, and making breakfast together, and going out to dinner as though they were still content newlyweds with only their new life together between them. As if the last week had never happened.

He'd lazily pushed himself deeper under the covers earlier that morning when Kendra left, anticipating a lazy, stress-fee day. She had brunch with her best friend every week, which usually turned into hours of shopping and all that "girly-girl" gossipy stuff some women couldn't live with out. Which left him to his own, junk-food-y, sweatpants-ed devices. He was more than happy to plant himself on his recliner in front of the plasma screen and forget himself for awhile.

And then the doorbell rang.

Casey brushed past him as soon as he opened the door; fidgety, nervous energy and last week had happened after all.

"Are you alone?" she asked in clipped tones.

She was working herself up into one of her states, flushed cheeks and hairs out of place, eyes flashing and hands shaking. He smirked in return, the instant her question sunk in for her. It carried very suspicious, sordid connotations, and she paused for a moment to look embarrassed.

Aware of his upper hand, Derek seized the opportunity to lean in a bit, just at the fringes of her personal space, "Yes."

"Good," she thrust something at him, "then you can explain this."

The item in question was her letter. He'd attached a post-it to the front before sending it back to her, a simple message in messy printing; 'Can't keep it.' The obvious implication being that he wouldn't destroy it either, which he'd thought was annoyingly decent of him.

But Casey had apparently picked up on other implications, "You're not going to tell Kendra."

He stared calmly at her in response, mentally working through the logistics of getting her out of the button-up top she was wearing. Not that he intended to put said planning into place; he just couldn't help himself sometimes. Picturing her naked was one of the best ways to tune her out when she started getting shrill.

"De-rek!" she glared, as though reading his mind, "You have to tell her."

Discarding his fantasies with a sigh, Derek returned his attention to the letter. He adopted a mock-orator pose with one hand on his chin, holding the paper in front of him at a pretentious distance.

"I'll leave it in your hands," he read aloud, fixing her with a pointed look.

"Yeah, well your hands are shaping up to be rather clumsy!"

"You didn't seem to think so when-,"

"SHUT UP!" she shouted, advancing a step, "you unbelievable bastard, don't even start. This isn't a joke."

Derek, for all his composure, instinctively took a step back at the sudden outburst. Clearly, she was far more pissed off than he'd thought.

"Do you see me laughing?" and he was starting to catch it, her anger, "I don't get it, Casey, why the hell do you want me to tell Kendra? I thought you, of all people, would prefer to just forget the whole thing."

"This isn't about what I want," she returned, "It's about you being honest with your wife. She deserves to know the truth."

"Why?"

"Because…" she paused, "Because it's the right thing to do!"

Typical.

"You're going to stand here and talk to me about The Right Thing now?" unsurprised as he was, he still had to ask, "So, I tell Kendra, and then what? Huh? The only thing that changes is that she's miserable. Is that what you want?"

She opened her mouth, closed it, pursed her lips. Of course that wasn't what she wanted.

"Anything to clear your conscience, though, right?" He laughed again, smugly, "It must be killing you to be without that precious moral superiority you're so fond of always flaunting."

She flinched at that, and Derek was sorry for a moment, until she met his eyes again with an expression that was more angry than hurt.

"Do you really think," she seethed, "that your marriage will last this kind of lie?"

"What difference does it make to you?" he ran an agitated hand through his hair, "Why did you even send that fucking letter if you were going to turn around two days later and stick your nose in everything you said you were going to back off of?

"Because, like it or not, I am involved in this. I feel responsible!" she cried, "And… and not telling Kendra isn't just wrong, it's the easy way out."

"But you don't want her to know," he caught her, "Not really. You're just retreating to your ethical sanctuary, because all the answers are neatly lined up for you in that textbook way you couldn't live without. Well good for you, but that's not my life. Get it?"

"No!"

"Too bad then," he folded his arms across his chest, "but you're going to have to deal with it anyway. My marriage, my life, my problem. Not yours."

Casey deflated slightly in front of him, gaze falling to the floor, "She's my friend."

"And I'm your brother."

He threw the word out there like an insult, taunting her, and her eyes snapped back to meet his with renewed fury. She was an easy target, susceptible to every piece of bait he offered, and he knew all the things to say to make her crazy, every button to push. He could write a guide.

"That's what makes this whole situation so much worse than your typical… your typical…" she threw her hands in the air, exasperated, "It's ridiculous! The idea of… of us, like this, was purely hypothetical! It stayed safely in our peripheral vision for years! This was never supposed to actually happen!"

Derek raised an eyebrow, "Are you sure?"

She stared, "Am I…? Yes! Yes. God, yes, I'm sure. What are you talking about?"

"Come on," he rolled his eyes, "How many years have we been playing this stupid game? Under any other circumstances, we would have-,"

"The only circumstances that matter, Derek, are the present," she sighed. "And anyway, even if everything about… even if everything was what it should be, you and I would never work. Even if we weren't related-,"

"By marriage!"

"Even if we weren't stepsiblings, we're still completely incompatible. We have nothing in common, we fight all the time, our personalities don't compliment one another at all. There's no way we could work in any Universe. No, this definitely should not have happened."

"Classic Casey," Derek, who didn't even know why he was attempting to argue her point now, but for the sake of it, sneered. "We're not by-the-books compatible in that cold, factual sense, so your freakish, Type A little mind just can't grasp how we could ever work. Don't you ever get sick of yourself?"

She huffed, "You just don't-,"

"I get it," he interjected with more feeling than he generally cared to exhibit. He didn't know why her words bothered him so much, but he was starting to lose control, "The fact is that I just had you up against my kitchen wall and begging for what you now say shouldn't have happened. The fact that we're stepsiblings didn't stop it, and neither did the minor issue of my marriage, so fuck compatibility. That obviously means something."

"I…" she was shaking all over now, from rage or weakness, or a combination of the two.

He expected her to storm off, but she was just as stubborn as he was, and he watched her begin to recover herself. Her quivering fists clenched as she took a deep breath, and loosened with her exhale. She steadied herself, smoothed down the front of her shirt in a very deliberate, slow manner, and looked somewhere over his shoulder.

"I didn't expect you of all people to suddenly turn wishy-washy," her tone was steel, "That was just sex."

This was what he'd initially expected from her, what he'd thought she'd put in the email she never sent. But here it was now, all the cool, business-like anti-sentiment, finally. Too late, though, because too much had already been said that was at odds with her new tone. Because her voice was hitting all the right notes, but her expression faltered, and her eyes were entirely vulnerable. She'd never mastered the art of bravado the way he had.

"Exactly. Just sex. It wasn't enough..." he swallowed, pushed himself into her line of vision again, "…To change anything."

She looked at him, confused, "It changed everything."

"Only for us," he explained, "And it was just a one-time thing that happened while I was technically separated from Kendra. She moved out to give herself some "space to figure things out," remember? I don't even know what she did about, or with, that Kerry guy, or any guy. I didn't ask, she didn't volunteer any info, and it doesn't matter because we're moving on. She wanted it that way. I think her exact words were clean slate."

Casey was silent for a moment, and he let himself believe for a few seconds that he had silenced her on the matter for good. She was definitely calmer anyway, coming away from all her righteous indignation and fury to something softer, and sadder. She looked lost, trying to reclaim whatever brought her here to begin with, but unable to see it.

He thought she might cry, and something in the pit of his stomach lurched, an unconscious, protective instinct that wanted her in his arms and smiling. She bit her lip instead, drawing his eyes to her mouth and he found himself idiotically moving closer…

"When we had lunch the other day," lips moved slowly with carefully measured words, "Kendra-,"

He clamped his hand over her mouth, and she remained surprisingly motionless as he drew even nearer, "I don't need to know."

She nodded, just barely, and he released her, fingers brushing softly over her cheek as he withdrew. But then suddenly, he was leaning into her again, drawn forward by some unseen force, like the last time, but less urgent. He was... going with the flow, following an impulse that didn't really seem to be in any hurry. It was a lull - the eye of the storm - and this was their sanctuary, the two of them at an impasse that could only lead them to what was lately proving to be inevitable. And he was simply... falling. Towards her in a quiet, trance-like state, while she waited for him, perfectly still…

"Derek," she breathed just before their lips met, quiet and careful, tentative.

And then, louder, "Are you going to put this on your clean slate?"

Fuck.

He retreated, the moment gone just like that, and he blinked to shake it off. That weird, drugged feeling. The haze of whatever the hell he'd just been caught up in. Her. His annoying, shrill, self-righteous, neurotic stepsister. There had been something, just then, that had nothing to do with lust or attraction, or anything physical. Not for the first time. It wasn't "just sex" with them, and never could be because look at how pitifully entangled they were. It was enough to make him want to punch something, hard, but he resigned himself - a little - instead.

"Maybe we should have dealt with this a long time ago," he said, surprised at the sincerity in his own tone, "Got it out of our system in high school when we could have left it at… hormones, or something."

"I thought you'd be out of my system after we… after Tuesday," Casey told him, matching his sincerity, ready to be honest, "but you're more in my system now than ever before. I was… I had my life just last week, and I was fine, but now I can't… stop… you're all I think about. Every night when I go to sleep, every morning when I wake up, and I just can't take it!"

Derek froze; she was starting to cry.

"I'm a mess," she sobbed, "I don't know what to do, and it's all… you, and your stupid universe and life was finally not revolving around you anymore and… and… I just… hate you. I hate you so much!"

"Uh," he fidgeted, her tears completely disorienting him because he still couldn't deal with a crying female, even as an adult. But there was returning anger cutting through the waterworks, and he seized it, something he could handle, "R-right back atcha."

"I mean it," she glared.

"I know."

"I hate you," she repeated, "You're so smug, and you just know the whole world adores you, and you… you swagger and I could just… just strangle you with my bare hands."

Without really thinking about it, and somewhat desperate for her to stop crying, he grabbed her wrists and brought her hands to his neck. Her fingers closed around his throat automatically, but gently, thumbs resting carefully at his pulse point. He could feel it race against her touch, and she exhaled shakily. It was something like acceptance, maybe just for a moment, because she was growing quiet again. Their eyes locked, up close, and her lashes were wet, her lids puffy, but she was so... Casey, he was being drawn right back in.

"Will it always come to this?" she whispered tiredly, even as she pulled him towards her.

"If you - door."

She blinked, almost dreamily, "Door?"

He pushed away from her, noting for the first time that they were still standing together in the front hallway, and the doorknob was turning, probably because the lady of the house was home. Casey caught on quick, and abruptly turned away to collect herself. And by the time Kendra came inside to find them there, they were at a respectable, if guilty, distance.

"Hey Kendra," Derek greeted her with a normal tone at odds with Casey's obvious distress, "We were just-,"

"I know," Kendra glanced worriedly at her sister-in-law, "fighting, right? You guys just never stop going at it, do you?"

He grimaced, "Who knew sibling rivalry extended so strongly into adulthood, huh?"

"Who knew," his wife dryly repeated. "Are you okay, Casey? You look like you've been crying…"

"Oh," she wiped at her eyes, "it's nothing. Derek was just pushing the usual buttons. Anyway, I should get going… um, I guess I'll see you guys at George's birthday next week."

"The big five-oh," Derek waved his hand, "Wouldn't miss it."

"Sorry, you have to leave so soon after I got home," Kendra said, "I'll call you later?"

"Sure," Casey pushed a smile onto her face with some obvious effort, "I'll talk to you later, then. Um, bye Derek."

She wasted little time racing out the door, moving as though fleeing a crime scene. Even Kendra noticed.

"That must have been some fight," she observed, "Would it kill you to be nicer to her, Der?"

"Why doesn't anybody ever say, Would it kill you to be nicer to Derek, Casey?"

"You're so hard done by," she rolled her eyes, "Anyway, forget that. What's this about your dad's birthday? You didn't tell me there was going to be a party."

"I'm sure I mentioned it."

"You didn't, and I had no idea he was turning fifty," she shook her head, "The present I was planning to send won't do at all, I'll have to go shopping – it's a big deal – remind me to call Nora later to find out what I can help with. Oh, and maybe we should bring something for Marti, too, since we haven't been back home for a few months and she's probably feeling neglected. I know she's not a child anymore, but still, it's the gesture that counts, right? And, let's see…"

Slightly overwhelmed – she was a good girl – Derek found himself slipping an arm around his wife's shoulder, to kiss her forehead just because he couldn't find the right words. Because he couldn't say he was sorry.

…………………

"Nora, hi," Derek was on the cordless in the kitchen, after dinner that evening, "I'm fine… Yeah, the movie's going well – haha, right, nothing crazy after that episode. Right, right. And how are things with you? Glad to hear it. Well, listen, that's actually what I wanted to talk about… I just don't know if my schedule will allow me to, uh, come."

"Derek," Nora easily shifted from her light-hearted chatting tone to The Mom Voice, "You are not backing out of your father's fiftieth birthday party."

"I wouldn't if it wasn't important."

"We've been planning this for the last month," Nora very reasonably reminded him, "You already told me that you'd be able to make it, no problem. What's changed?"

"Just… you know, movie stuff," Derek hated how vague he was coming across, "It's a very unpredictable line of work you know."

"Uh-huh," she was unconvinced, "this wouldn't have anything to do with Casey, would it?"

Busted!

"What?" he laughed, "Of course not! Why would it?"

"Well, wouldn't you know it, I just got off the phone with her before you called. Lucky me," dry, parental, your-so-full-of-shit mode engaged, "to have two kids phone home in one day, and within minutes of each other! And, what a coincidence, for the very same reason. Almost spooky, isn't it?"

"Almost," he absentmindedly agreed, "So… Casey's not coming, huh?"

"She thought she wasn't," Nora said, "But I managed to persuade her with the same reasons I'm about to use to persuade you to come."

"But-,"

"Derek," now she was perfectly serious, "I know you're all grown up now, and I know that in spite of that, you and Casey still have the tendency to get on each other's nerves. But, we've always been a close family, and even though your father isn't looking forward to turning fifty, he is anticipating having all his children there to celebrate with him. I think that's the least you can do. Never mind the fact that Marti has already been told that you're going to be there and she's already planning all the ways she'd going to talk you into letting her come to Toronto for a few weeks this summer."

Derek smiled slightly; what a brat.

"So," Nora concluded, "I'll see you Saturday, right?"

He sighed, "Yes."

"Good. I didn't want to have to tell your wife on you."

He laughed at that and, seeing said wife enter the kitchen, "She wanted to talk to you, by the way, do you still have a minute?"

"I have an hour," the return of the dry tone because his stepmother knew Kendra.

"Perfect," he handed the phone over to its true owner, "It's Nora."

… And had it snatched eagerly out of his hands.

Derek didn't stick around to hear the onslaught of high-energy chatter that was bound to follow, retreating to the living room where the TV was waiting.

But he couldn't concentrate on it, mind otherwise engaged with too many other things. Casey, specifically, and how the hell they were supposed to act around each other in front of their family this weekend. He thought of her earlier, shouting, and pissed off, and crying. How she'd felt pressed between him and the wall, gasping into his mouth. The way she'd looked wounded, and lost, and angry while she told him she couldn't stop thinking about him.

He couldn't stop thinking about her.

Before he knew what he was doing, he had his cell phone out of his pocket, her phone number at his fingertips.

She waited until the ninth ring to answer, and he knew she hated that she'd even answered at all, "What do you want, Derek?"

"You," he replied automatically, irritably banging the back of his head against his recliner the moment he realized what he had said.

"Stop it," she commanded, "God. Why are you doing this?"

"I don't know."

Silence. For thirty agonizing seconds.

"What," she finally found her voice again, "What are we supposed to do with this?"

"I don't know."

"Why can't we just leave each other alone?" her voice catching.

"I don't know."

"I hate you," obviously crying now, "Please… just let me… just… I hate you."

"I know."

She'd told him, over the years so many times, and the words were somehow never really what she wanted them to be.

She hated him.

And he knew that this was a placeholder, just like he knew that she meant it.

…………………

"All your mental armor drags me down;

Nothing hurts like your mouth…"

- Bush

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