A/N: Hi ! Thank you so much for the reviews you left on the last chapter, I really appreciate all of them! :)

Some of you have only started reading this story recently, so I want to set an official timeline so it won't get confusing lol. I know that in the first season they are 14/15 years old, and this story also starts somewhat around the 1st season (after the party episode, obviously) BUT this is a more of young adult story, so they are both in the 11th grade. Derek is 17 already (He's a gemini sun/scorpio moon and you can't change my mind) and Casey will be turning 17 soon too (I'm ignoring the fact that Derek had to repeat the 1st grade, forgive me). Hopefully this makes everything clear, but if you have any doubts or thoughts, let me know! Enjoy :)

PS: Casey is, in my opinion, a Scorpio sun/Virgo moon. Thoughts?

—

Everything was shit. There was no other way around it- everything was shit.

Derek had barely slept on the weekend that followed the party, mostly because he had a monstrous hangover that seemed to last for most of it. He vomited right after waking up on Saturday (not a pretty picture), with his stomach contracting in pain, trying to expel everything he had eaten and drunken the night before. He still didn't know what was in those flasks, and now it was pretty safe to assume it must have been something eerily close to poison. Not that it mattered anyway, on day two of the longest-hangover-ever-seen, he just wanted to sleep. Which he couldn't, because he still felt like shit. His body was definitely punishing him for his reckless behavior, and it was working, since it resulted in Derek's empty promise to stay away from alcohol for a long time.

Maybe he was getting sick too. It was now the early days of November and the flesh-eating cold was settling as the recurrent weather, so it was very much possible that Derek was simply coming down with a nasty cold. Either that or he had really been poisoned. At that point, under three cozy blankets and armed with a puffy, unsexy pajama Nora had gifted him last Christmas, he couldn't give two fucks. Sick, poisoned, hangover'ed- it didn't fucking matter. What mattered was that he had a sharp headache and that he couldn't, for the life of him, get out of bed.

Saturday came and went, spent uselessly by Derek under the covers rethinking most of his life decisions. The faint, incomplete memories of the Halloween party plagued his brain like a virus. There wasn't much he remembered, actually most of the night had been repressed by Derek's drunken mind, but there were still a few things he was certain of:

1) Drinking; a lot (too much).

2) Dancing; badly.

3) Casey disguised as Cat woman?

The Casey memory was barely that, since it was about as foggy as the set of Twin Peaks. He was sure it had been just a fever dream until he found her black mask next to his bed. He touched it cautiously, afraid it would burn his fingers through the bone, and stared helplessly. Until then he had clung to the hope that it had been just a stupid dream, one he could file in his brain under [Casey dreams- Do not analyze], and not a real conversation with her. The details of their interaction remained vague and confusing, except for the way her eyes pierced through him from behind her mask and the way his own laugh rang in his ears- those details were painfully clear. Derek also remembered the discrete sound of her giggling, so maybe he wasn't the only one laughing. Oh, and he also had the image of her lips trembling burning in his eyelids. It was the exact moment before she turned around and left him there, hopeless and dazed.

I don't know you, you don't know me.

Unfortunately, that sounded about right.

If only he could remember what the fuck he said to make her run away from him like that. From his inability to think about literally anything else, Derek concluded (on a sticky, raining Sunday morning), that he did feel bad about the way he left things with Casey. He had no idea why he behaved like that, but he was certain he didn't mean to push it that far. Until then upsetting Casey was nothing more than a joyous hobby, a day to day escape from boredom, yet now he actually felt bad about it. If it wasn't humanly impossible for Derek to say sorry, he worried he might just blurt it out the next time he saw her. Especially because he could imagine the storm he was in for when they crossed paths again. Casey was a very worthy opponent, and she could raise hell just by lifting her delicate fingertip, so Derek silently prayed for her to have the slightest of mercy on him.

That Sunday night Derek tricked his body into finally falling asleep, ignoring every dull and annoying ache that had now reached almost every limb. Another silent, unconscious prayer was summoned when he started dreaming about Casey. She was hovering over him, furiously holding his body down with a sharp spear clinging to her left hand, from which droplets of blood were raining down. He noticed the way his heart was thundering inside his chest, thud thud thud, and even though he couldn't hear much besides the strain, tired hum of her laugh, some words seemed to float in-between. Casey… I'm so sorry… Don't do this.

You, was all dream Casey had to say in response to his begs of mercy. There were about a million different ways to interpret that electrifying you, but Derek couldn't get to any of them before he woke up, gasping and drenched in sweat. Now that had been a fever dream he would rather not analyze. Casey holding a murder weapon was theoretically hilarious, but Derek couldn't even think about laughing. Just remembering the beastly glaze in her eyes was enough to make him start sweating again.

Every time he tried to go back to sleep, that broken you echoed around his head, keeping him wide awake. In truth, he didn't need to analyze his visions. The message was clear: he had fucked up and as of next morning, things would probably never be the same again.

—

Monday morning

To the outside eye, the world hadn't changed one bit.

The sky was cloudy, as if often was, stealing away any hints of sunlight. There were tired students running around campus, holding on to their knee-high socks and thick scarves on their way to class. Derek was among them, hurrying his step through the school since he had gotten out of bed about twenty minutes too late. The direct results were disastrous, untamed hair and the lack of will to live.

Casey was sitting at her usual seat, with her legs crossed tightly beneath her desk. She let out a soft, annoyed huff the moment Derek barged into the classroom, discreetly following him with her eyes until he took a seat at the back. He mumbled a disgraced Sorry to the teacher out of reflex, before sitting down and basically hiding behind his backpack. It definitely wasn't ridiculous the way Casey made him feel so small, and it wasn't pathetic that he was hiding his face from her as if he were scared to find a sharp spear trapped between her hands. Thankfully there wasn't anything ridiculous about any of it.

For the rest of the day, Derek avoided Casey like the plague. His integrity was still very much compromised after that devastating hangover, and Derek had no plans to damage it any further. He couldn't even bring himself to flirt with her friends, even if they were begging for his attention. Normally he would love it and immediately bite their bate, but that morning everything felt so out of place that Derek worried their reality would simply break.

Apparently three days without sleeping could really make a guy drown in absurdity. Deep down, the world was still as it was. Casey was mad and Derek would just have to make her unmad again. It wouldn't be easy, Casey was still very passionate about hating him and the idea of them pretending to be strangers, but surely he could think of something that would make her hate him a little less.

In a weird way, her reaction was already a victory. It was far better than her ignoring him (because that's what really hurt his ego).

Maybe Derek just liked knowing that in a bizarre, dysfunctional way, he mattered to Casey.

—

The real trouble however, started on Thursday. It was raining, unsurprisingly, and Derek had been held up after his French class. He was sitting on his desk, drumming with his fingers nervously against his thighs, waiting impatiently for Mrs. Morris to come back from her smoke break (Derek only wished he could've gone with her). He had no idea why he was being held up, for once in his life he didn't think he had done anything wrong. There had been a test the previous week and even though he knew he wouldn't do well on it, he didn't try to cheat. In all honesty, the anticipation was building in the pit of his stomach and Derek couldn't remember the last time he had felt so nervous around a teacher. He really didn't feel like himself.

"Mr. Venturi." The teacher called, grounding him back to reality.

She walked towards her desk and sat down, motioning for Derek to sit in the front next to her. The idea of sitting in Casey's seat tempted him for a few seconds, but he brushed it aside, opting to sit closest to Mrs. Morris' desk instead.

"You failed your test." She said, very unceremoniously.

Oh.

"Oh." The word came out more like a whisper than what he intended to. Derek at least appreciated her honesty. He cleared his throat and proceeded "Yeah, I'm really sorry about that, I didn't have time to study…"

"You can stop, Mr. Venturi." She interrupted, twisting her face until she looked like an old frog "Mrs. Hastings already showed me your school report. Apparently you haven't had time to study since the 8th grade."

"I'm very busy." Derek managed to choke out before attempting to smile in the most innocent way possible.

"I bet you are." Mrs. Morris nodded in fake agreement "But at this school, I'm afraid you'll have to try a little harder. You can't fail anymore, Derek."

"I-I won't fail again, I promise."

"If only I believed you." She sighed "Unfortunately, I don't. So I spoke to Isabel about your case."

Derek felt his knees nearly give out. He wasn't afraid of detention, nor was he afraid of the threat of expulsion, but just picturing his father's face if he was ever shipped back home was enough to make his legs tremble with uncertainty.

"And…?" Now that was definitely a hoarse whisper.

"And we will assign you a tutor."

"Oh, that sounds fair." And boring.

"We discussed it for a while, and I think we've managed the perfect solution for you."

Maybe it would be a hot senior who would just happen to fall in love with him too- if only life were that kind.

"We think Casey would make a great tutor for you." She smiled, as if there was anything to smile about.

"C-Casey?" He repeated, hoping he had misheard the news or that his teacher was talking about another Casey (any other Casey).

"Yes, Casey MacDonald. She's your step-sister, right?" Derek nodded unhappily "Great, so you two already get along. She's a dedicated, enthusiastic student, and I think you would most definitely benefit from this arrangement."

Oh no.

"Listen, Mrs. Morris…" He had no idea where he was going with that sentence, he only hoped he could invent some bullshit to convince her to do anything else. "I hear you, loud and clear, I need to study harder and that I will do. It's a Venturi guarantee."

"Mr. Venturi, I'm not going to spend another minute of my precious lunch break discussing this with you." His teacher warned, looking away absently, in search of another cigarette inside her enormous handbag "If you have any further problems, go bother Mrs. Hastings instead."

Derek rubbed his arm nervously, digesting all that was being said.

"Have you spoken with Casey about this yet?"

"No no, not yet, but I'm not at the least concerned about it."

Well, at least one of us isn't.

"I think Ms. MacDonald has proven she's receptive to school-related activities, and mentions of extra-credit may tempt her to take up my offer." She was now holding her cigarette, clearly eager to be left alone.

Derek was dying to get out there too, the air had become thicker and increasingly harder to breathe through, and he found himself struggling for breath.

"I won't take any more of your time." He politely said, standing up on his still very unsteady legs.

"Lighten up, Mr. Venturi." The teacher smiled with her crooked mouth at Derek, who was already leaning against the doorframe ready to leave "I think you will enjoy Ms. MacDonald's company."

Derek nodded out of sheer politeness, his lips pressed together in a disguised frown. He hated that she had said that. He hated the way Casey's image lingered in his brain when Mrs. Morris mentioned her, nibbling on her pencil, arched over her books… Doesn't she understand that that's exactly what he is scared of? Enjoying her company.

—

Thankfully, Casey wasn't making that easy.

On that same Thursday, as daylight faded into an indigo blue mist, Casey ran into Derek. More like she personally sought him out, making her way around campus with a very heated expression printed on her face. Derek saw her coming from a mile away, he could recognize her anywhere with her high knee socks and grey uniform skirt, both impeccably ironed. Her hair was slightly curly, maybe due to the light rain that had plagued that afternoon.

He was standing outside the old ice rink, leaning against the wall, lazily holding a cigarette while half-listening to Parker gloat about his incredible game stats. Derek wondered if he should perhaps hide his cigarette from her to prevent a lecture on why smoking is so bad for him but decided against it. He wanted to shock her with his new filthy habit; anything was reason enough to earn a reaction out of her.

Truth was, Derek half-expected her to get freaked out about approaching him in broad daylight, especially with Parker right next to him, but unfortunately, Casey held a stable reputation as a fearless, get-everything-her-way kind of girl. Derek usually appreciated that, unless it didn't benefit him, as it most often didn't. Her pace was steady and determined, her long legs swaying side to side as she came closer. In the blink of an eye, she was already standing right in front of him, with fury glowing in her misty eyes, and Derek was suddenly very much aware of her sweet scent and how his own fingers trembled when he tried to secure the cigarette.

"Derek." She said dryly, not bothering to acknowledge Parker. "A word, please."

Derek nodded immediately, giving Parker a lazy head nod before following her until they were somewhat hidden behind an old tree. He took a deep drag of the cigarette, let the smoke fill his mouth and lungs, and put it out, stepping on it a few times with his dirty sneakers.

"Casey…" He awkwardly choked out when he faced her "Hi."

"Shut up, Derek." She huffed, folding her arms across her chest. "I can't believe you failed your stupid French test. I can't believe I have to be your stupid tutor, because you're so… SO…"

"Stupid?" He added, hoping to make her laugh. He had no such luck.

"So fucking stupid."

Derek didn't exactly know how, but her eyes were now reflecting the exact purplish shade of the sky (it was terrifying how she did that).

"Casey, did you actually say yes to this?" He asked, rubbing his temples.

She looked surprised at his accusation. What was she supposed to do? Disrespect a teacher and lose an opportunity to improve her future C.V? As if.

"Well… Yes. I had to! Mrs. Morris insisted that I help you, that it would be good for you, blah blah blah. I'm only doing this for the extra-credit Venturi, so you better behave or else I'm going to rip your hollow heart right out of your chest."

Derek had the sudden urge to laugh, not because it was particularly funny, but because it reminded him of his delusional dream with her. She may as well be holding that spear right about now. He suppressed his urge with a husky cough, watching her attentively.

"We're meeting tomorrow night at the library, at 9 pm. Don't be late. Don't talk. Don't even think about breathing around me…"

"You're taking this really well, Case." Derek interrupted, grinning like a little boy.

"Fuck you, Venturi."

"See you tomorrow, Casey." He smiled, annoyingly charming.

Casey rolled her eyes at his nonchalant attitude. Didn't he care at all about how unbelievably mad she was?

Apparently not, because he was still smiling, right until the very moment she started walking away from him.

But, much to his pleasure, she turned around.

She flattened her shirt, took a deep breath and with a venom dotted voice said "You should stop smoking. It's really bad for you."

Which made Derek laugh.

—

Casey meticulously combed her hair with her fingers. Obsessively touching her hair whenever she was impatient or nervous was a weird habit of hers, one of those you couldn't shake off no matter how hard you tried. Right now she was a bit of both: impatient because Derek was officially four minutes late, and nervous because the thought of her being his tutor suddenly struck her as a really bad idea. Not because Casey doubted her teaching capacities, she had great confidence in herself, but because it was Derek who she was tutoring.

Lazy, obnoxious, uncooperative Derek.

It wouldn't go well, obviously, and she would be the one to take on the repercussions of his failures. Also, people would see them together, which would be weird and lead to uncomfortable assumptions. Small boarding schools were the perfect environment for rumors to really grow and flourish. Keeping their meetings a secret would be nearly impossible, so Casey was just about ready for the gossip to start traveling around.

Her hand rested on her thigh, attempting to control the restless burning inside her. Derek should've been there by now. Even if he was trying to annoy her, which was the most obvious reason for his tardiness, almost ten minutes were sufficient to make his point.

Just as she was about to get up and leave, Derek appeared. He was making his way over to the table with his hands burrowed deep in his pockets and a somewhat serious expression drawn on his face. Casey knew that look, and it wasn't nearly as menacing as he probably thought it was, it simply let her know that he was stopping himself from smiling. His hair was neatly combed with only a few wild waves of hair hung in front of his face, and he smelled good. His uniform was ironed and completely free of stains and he smelled good. Not that Derek reeked all the time or anything like that, but this wasn't your usual deodorant and basic body wash combo; this was cologne, men's cologne and it smelled ridiculously nice. The last time he had tried that hard to look good was when he finally scored a date with Lisa Henries (a voluptuous senior he could not stop talking about) back in September. And the last time he had that amount of shampoo or body wash on him was during their bathroom fight when they were locked in the bathroom.

In short, it was a rare occurrence that Casey seriously considered celebrating.

"Casey? You spaced out there a little there." He said, a sly smile curving on his lips.

"Oh…" Casey swallowed, focusing back on reality "Sit. You're ten minutes late, Venturi."

"Maybe you're just ten minutes early, Case."

Derek winked, cocking his head to the left. Maybe he forgot he wasn't talking to one of his conquests and that Casey wouldn't melt under his fingers and words. Maybe he simply forgot to account for the fact that right now she despised him, so much so that her fingertips were trembling and her stomach was tight with knots. Rage. Probably.

"Let's just get to work before I regret this." She sighed, grabbing her book and notes.

"Why did you agree to do this?"

"Because I had to." Derek was pushing her, she knew it, he was playing games and getting her on edge to delay actually having to study. "Why did you fail the stupid test?"

"Because I'm dumb." He breathed out fast, rubbing his chin.

"You're not." She shook her head "I wish you were; that'd be simpler. You're just lazy."

"Outrageous."

"Obvious." Casey huffed, running her fingers through her hair. "Not counting the times when you're holding a hockey stick, you never work hard. And you only try hard at that because you're allowed to act like a gorilla on steroids. You don't take anything seriously, Derek, so don't bullshit me."

Those words shouldn't have hurt. They should have flown by him before dissolving into thin air without a second thought. He knew he was lazy, had always been, and he did appreciate the chaotic nature of hockey. It was all true, so maybe that was the reason why it felt like Casey had just struck him in the guts with a dull knife. Ouch.

He was sure he was frowning now, which should have satisfied her in the least. And if she was, she wasn't showing it. Her plump lips were pursed and her eyebrows were furrowed together in concentration. There wasn't so much as a hint of a smile; nothing.

"I can take things seriously; I simply choose not to. Life's more fun this way. You should try it." Casey did not appreciate the sarcastic tone in his voice.

"Is it fun, Derek? To breathe through life without a care, without a passion, without making any meaningful connections? To know that at the end of the day everyone is disappointed with you? You must be having a blast."

Derek took a deep breath. Did Casey really want to go there? To argue about the bullshit meaning of life and present her three-point argument of why she was so much better than him?

"Very fun indeed, Case." He spit out, forcing a smile "Much more fun than spending every second of every day perfecting myself to live up to an impossible standard of glorious success. You want to be admired so freaking much that you forget that people should like you too, not just look up to you as the holy grail of perfectionism. Would you consider those meaningful connections, Casey?"

"You are such a fuckhead." She sighed, not sure if she should scream or cry. Little did he know how lonely she really felt. "The only meaningful thing you do is ruin other people's lives just to get your way."

"Oh yeah, I'm the one always trying to get their way. That's rich coming from the suburban princess who manipulates everyone around them."

"I don't… I don't do that!" Casey stuttered, blowing air out of her nose. "You really have no self-awareness whatsoever, Derek, I don't know why I bother."

"Stop deflecting. I know who I am and I'm okay with that." Lie. "You, on the other hand, are just a mix of everyone else's unrealistic expectations and your own insecurities. You need to get over what everyone else wants from you and just be whoever the fuck you want to be."

Casey was silent. Derek was slightly out of breath, his chest rising rapidly. His mouth was so dry even his throat felt like sandpaper. He hadn't had time to feel sorry for what he was saying, but he knew it was harsh. Not that Casey could be absolved either, she really trying her hardest to sting him with her words, and somehow it was working.

"Don't pretend you want me to change." She said, chewing on her lips "You like that I'm useful to you. Every time you fuck up, you rely on me to help you or to at least share the blame! You always to me for help; I always have to clean your fucking messes! That's exactly what's happening right now: you failed your test, and I'm here wasting my Friday night at the library with you."

"As opposed to being at a party or hanging out with friends?" Derek scoffed.

"Fuck you. That's not the point."

"I didn't choose to be here with you either." He whispered, almost like he didn't want Casey to hear him.

"Then don't be." Casey smiled "Since I'm just so unlikeable, how about you get back to your great parties with those hockey ogres and get out of here, huh?"

Silence.

Derek had his hand on the back of his neck, massaging his tender skin.

"So, I ruined your life, huh?" He cleared his throat, speaking softly.

"Mostly." Casey frowned "Because of you I had to move houses and schools twice in just a few months. You've made my life hell. And now we're here and I'm alone."

"You're not alone…" He tried to say before he was interrupted.

"I am. I can't count on you, Derek. I think we both know that by now."

There was a certain sadness to her voice that Derek wished he hadn't noticed. He wanted to lie to her, tell her she wasn't alone and that he was sorry, but it wouldn't mean anything- and she wouldn't believe it either. So he watched her silently, wondering if he was maybe imagining the tears welling in her big eyes.

She sniffled before speaking.

"I think I'm gonna go."

"What?"

"Yeah." She sniffled again, collecting her books before she handed Derek a neat stack of paper "Here are my notes for this semester. Read them if you want, we'll do this some other time."

"Casey…" He said, almost like a prayer. Absolution sounded great right about now.

But it was all in vain. Casey rarely changed when she set her mind to something. Before he could call out to her again, she was already long gone. Well, this went well.

Derek felt bile and spit rise up in his throat, forcing him to swallow it back down. He wasn't sure what he could do now; realistically it seemed like a sure dead-end. Truth was, Derek wasn't born with the power of reconciliation, usually people just forgave him because he could charm his way out of trouble. But of course, with Casey it was different. They were immune to each other's charms and powers, which made everything a thousand times more difficult. Now he really had no idea how, and if he could even fix this.

"I'm sorry." He mumbled under his breath, rubbing his temples.

Fuck.

—

A/n: Am I evil for making them fight like this? Yes. But Rome wasn't built in a day and "enemies" to lovers is a long road to take. Hope you enjoyed this! I have big plans for the next chapters…. Specifically one about Casey's birthday. Hmmmmm what could go wrong there, am I right ladies?