When Derek woke up, his bed was empty and he was not happy about it. Because when he'd fallen asleep, Casey had definitely been curled up next to him, and he had very much hoped to wake up that way for the second morning in a row. He groaned into his pillow and rolled onto his back, staring up at the ceiling.

"What's your problem?" came Casey's voice from the corner of the room. Derek scrambled upright to find her sitting at his desk, three notebooks spread out in front of her, and a pen behind her ear. She was wearing one of his old hockey jerseys and nothing else and holy shit was it fucking sexy.

"N-nothing. Thought you'd left," he replied, voice cracking at the end. He didn't have time to get embarrassed about it because he saw her bite back a smile and all he wanted to do was pull her back into bed and pull that jersey off- no, leave the jersey on, and not stop until she was moaning his name.

"I'm making to-do lists," she interrupted his thoughts, voice light and airy. He was snapped out of his much more fun thoughts and sighed.

"To-do lists? As in more than one?" he asked. She rolled her eyes and pulled the pen out from behind her ear so she could begin writing in one of the notebooks.

"Yes, Derek. There's a ton to do before we leave and I just want to make sure I don't forget any of it," she snipped.

"Like pack our bags and get on the plane?" he asked. She glared at him.

"Yes. But also, I still need to go say goodbye to Em, I need to go visit my mom, I need to buy a few things. And then there's making sure everything is in order here for the next couple of weeks. I was thinking I could pre prepare a bunch of food and freeze it, so all you have to do is heat it up. Which means adding grocery store to the list and…oh my God, I'm never going to get all this done!" she exclaimed, her voice reaching a high pitch squeak it only did when she was freaking out. He had heard it a million times.

Normally when Casey freaked herself out like this, he'd just roll his eyes and seek shelter from the impending explosion elsewhere- either in his room or by leaving. Except right now she was in his room and he had zero desire to leave. In fact, he found himself getting out of bed and walking over to her, without so much as thinking about it. He ignored the confused look she gave him and instead, he wrapped his arms around her and pulled her against his body. At first she just sat there, rigid, but quickly she wrapped her arms around his midsection and he smoothed down the back of her hair.

"It's gonna be okay," he found himself saying. He didn't know if that was the correct thing to say- after all, they were just talking about to do lists (right?), but he figured she needed to hear it.

"I know," she sighed, burying her face against him. He was standing and she was still sitting and he could feel her breath through his shirt, dangerously low on his abdomen. Instead of thinking about what it would be like if she say, just moved her face down a little further, he cleared his throat and stepped away. She frowned up at him.

"So- so- so why the three lists?" he asked, trying to distract himself.

"One is visits, one is shopping, one is action items," she replied, turning back to her notebooks.

"Action items?" he scoffed. She nodded.

He put his arm around the back of the chair and leaned over, pretending to study her meticulously organized and neatly written lists. Even though he always teased her about being a keener, he kind of loved it. Fuck. There was that stupid word again. LIKED. He liked it.

"Can I see your pen for a sec?" he asked. He felt her side eye him and expected her to say no, but instead she wordlessly handed him the pen. He took it from her and picked up the "action item" list. She snuck a glance at her and she was watching him with a look of curiosity and suspicion. He clicked the pen and tilted the notebook up, so she couldn't see it.

At the bottom of her 17 item list, he wrote the number 18, and then wrote his name in big bold letters next to it. He smirked to himself and then handed the list back to her eagerly waiting hands. Her eyes scanned over it and he saw her get flustered.

"Der-ek!" she snapped, whacking his arm with the notebook. He laughed.

"Now I have to start this list over!" she exclaimed, exaggeratedly slumping back down into the chair.

"Why?" he asked.

"Because I take my to-do lists seriously!" she replied.

"Come on Case, you think I don't know that?" he asked, crouching down next to the chair so they were eye level. She glared at him and he couldn't help but feel himself smile. No matter what…ugh feelings, he might be having, riling her up would never get old.

"Of course I know how seriously you take your lists. Gotta check off all those boxes right?" he asked, smirking at her. He thought for sure, she would smack him again, maybe over the head this time, but instead, she just stared back at him, expressionless for a moment, before tackling him backwards onto his bed.

"You are so annoying," she breathed, staring down at him with those insanely mesmerizing blue eyes. God, he could watch her stare at him all day. He was going to shoot back some sort of half assed comeback, but she silenced him with a kiss and all logic and reasoning and comeback abilities flew out of his brain.

He kissed her back passionately and slid his hands up under the jersey. She wasn't wearing underwear and fuck- he was already so hard. She straddled him and pressed her hips into his, the only thing separating them was the thin fabric of his boxers and he could feel her heat through them.

She began trying to pull them off and he eagerly helped her, tossing them to the side and looking back at her in time to see her staring down at him. He didn't couldn't decide whether he should tease her or be flattered by the look on her face so he went for both.

"Like whatcha see?" he asked, trying to sound casual, like he was joking. Her eyes flickered back up to his face and a pink flush spread across her cheeks. He got even harder.

"Sorry, just…it was dark in the cabin, so I didn't really…see…anything," she replied, sounding like she'd just been caught doing something she shouldn't have. Which was not the case. Honestly if she just wanted to stay there and stare at his dick all day long, he would have zero problem with it.

He was about to tell her this, when she looked back down and tilted her head to the side. Suddenly, he was the one that felt self conscious, like she was evaluating him or something.

"Can I…um…" she started to ask in a quiet voice. He didn't know what exactly she was asking but he felt himself nodding furiously. She smiled softly at him and he felt her hand wrap around his shaft. He drew a sharp intake of breath and all of the times he had imagined this moment did not even come close to what it felt like just to have Casey touch him. He'd been with more than a few girls and done some kinky shit over the years, and absolutely no one compared to what relatively little he and Casey had done.

She moved her hand up and down his length at a slow pace, staring at her hand as she went. He let out a small moan and it seemed to encourage her.

"It's big," she mused quietly, almost to herself. He hadn't known it was possible to get harder than rock hard and yet, that did it.

"Case," he breathed out, his voice a strangled whisper. He glanced down at her and saw that she seemed to be sliding lower down onto the bed which meant-

"Fuck," he groaned as he felt her tongue swirl around his head, experimentally.

"I've never done this before, either," she said quietly, her breath making him shiver.

"That's okay, just don't use your teeth," he joked. She glared up at him and usually her glares egged him on but this one shut him right up.

Her tongue made another circle around his tip and then she took him into her mouth and he almost came right then and there because all he could think was "Casey's giving me head". Slowly she brought her mouth back up and down the length of him and a loud, strangled moan escaped from deep within him. She paused, probably listening for footsteps outside the door, and then kept going. After the first few times, the suction grew more intense and he didn't even bother to stifle the sounds she was pulling from him. If she hadn't mentioned that this was her first time giving a blowjob, he never would have known. It was the best one he'd ever gotten.

He had to do everything in his power not to cum so he tried to think about other things but then he'd catch sight of those eyes of hers, looking up at him, as she took more of him into her mouth and- holy fuck, he was in ecstacy.

"I want-" he started to say but the rest was lost in a guttural groan as she pressed forward, deepthroating him, something he thought he'd only ever day dream about her doing to him. She made a small gagging noise and he could see over her head to where his name was spelled out across her back, almost like she was his, and he'd never been so turned on in his entire life.

"I wanna fuck you," he managed to rasp out, once she'd come back up for air. She gazed up at him, eyes hazy and lips swollen and he almost lost it right then and there. She nodded quickly and climbed up next to him on the bed. He slid the jersey up her body, planting kisses all over her warm skin as he did so.

"You're so fucking hot, Casey," he murmured, lips brushing softly over one of her nipples. She wiggled against him, his tip grazing against her and he lost his breath at how wet he could feel she was.

"So are you," she whispered back. He'd had girls call him hot before but something about her saying it was different. She wasn't as easily impressed as those girls. In fact she might have been the most difficult person to impress in the entire world.

"Derek," she practically whimpered, rubbing herself up against him again.

"Yes?" he asked teasingly. Her eyes flashed with annoyance and he couldn't help the slow grin that spread across his face.

"Just do it," she snapped quietly. He guided himself to her entrance and slid his tip up and down the lips, but didn't put it inside her yet.

"Do what?" he asked. Of course he knew what she meant. But he'd had this fantasy of Casey asking him to fuck her for so long that he just needed to hear it. Just this once. Even if she wasn't really his and it was just for sex, like she'd said. Whatever.

"Derek," she sighed. He continued teasing her as he leaned forward and began kissing and nipping at her neck, the way he'd come to figure out she loved. He loved it too- the morning after they'd first done this, he noticed she had a hickey at breakfast and the fact that it was from him had made him a lot happier than it should have.

"Derek, please," she whined, her nails dragging along his back. He bit down harder and she gasped as his tongue circled around the spot where he'd bitten.

"Please what?" he asked, vaguely aware they were now fucking the way they fought. He could have sworn he actually heard her growl in frustration, before she tangled her fingers in his hair and pulled his face to hers so they were nose to nose.

"Please fuck me," she whispered and if he could have recorded her saying it and made it his ringtone, he absolutely would have. He wasted no time, thrusting inside her and gripping her hip with one hand. She moaned and pulled him into a kiss and normally he didn't kiss girls after they'd just gone down on him but with Casey, who fucking cared? He kissed her back messily and thrusted into her again, this time a lot harder. She gasped and he smiled and he was pretty sure this was the best morning of his entire life.

His thrusts grew harder and deeper and as he felt his climax arising he reached down between them, playing with her clit like he'd done the first time. She reacted just as wantonly this time and when they came, they came together and never had "Der-ek!" sounded so good leaving her lips as it did when it happened.

He tried to roll off of her, when they had caught their breath a little, but she snaked her arms around his middle and wouldn't let go.

"What about the lists?" he joked.

"Fuck the lists," she mumbled, pressing a kiss to his shoulder. He chuckled.

"I think that is the second hottest thing you've ever said", he said, rolling off of her so he could look at her. She frowned slightly at the loss of contact and he pulled her into a gentle kiss. They both sighed happily and all he could think was that no matter what lies he told himself, there was absolutely zero way he could deny that he was in love with Casey McDonald. And had been for a lot longer than he cared to admit. And it was, perhaps, the single most terrifying realization he had ever come to in his life.

"We should really get up," she said, but made no move to do so.

"You do that. I need to regain my strength," he joked. She laughed quietly but it was interrupted by a knock at the door. They both froze and he felt his heart drop into his stomach. They stared at the door in fear.

"Say something," she hissed in a whisper.

"Uh…yeah?" he called out.

"You guys do know that we're still here, right?" came Edwin's voice from the other side of the door. Derek felt Casey look at him frantically and tried to sound casual when he answered again.

"You guys?" he asked, pretending to be confused. Edwin sighed dramatically.

"Yeah. You guys. You and Casey!" Edwin called back.

"Did you tell him?" Casey hissed. Derek glared at her.

"No. Did you tell Lizzie?" he asked. She bit her lip and he rolled his eyes. Not that he really cared if anyone knew. Maybe then she wouldn't be so freaked out and try she'd stop trying to convince herself it was just sex. At least he hoped she was merely trying to convince herself.

"I just came in here to borrow something, Edwin!" Casey called out. Derek looked at her, exasperated.

"He's not going to believe that," Derek whispered. Casey smacked his arm and shushed him.

"Can I come in then?" Edwin asked.

Casey and Derek looked at one another and before either of them had a chance to do anything, the door swung open.

"Edwin!" Derek and Casey snapped at the same time. Casey jumped out of bed and pulled Derek's jersey down so her whole body was covered. Derek pulled the covers up over his lap. Neither of them needed to do this, however, because Edwin had opened the door covering his eyes.

"Okay…I'm gonna look now…" he said, and tentatively dropped his hand from his face. Derek almost burst out laughing at the look on his brother's face once he saw Derek shirtless in bed and Casey standing there wearing just the hockey jersey.

"I uh…shit…sorry," Edwin mumbled in Casey's direction, focusing his eyes on Derek.

"This isn't what it looks like!" Casey blurted out. Derek rolled his eyes again. Did she not realize the jig was up and no one cared?

"I came in here to borrow um…a pen. And Derek was…watching porn. Just like…super loud porn and then-" Casey attempted to make up a lame cover story which by the look on Edwin's face, he was not buying. Edwin didn't look at her while she was talking.

"Right. Okay. Well I just came to remind you guys that we're still here. Lizzie and Marti are downstairs but I just woke up to…whatever…this was-" Edwin started. Casey cut him off.

"It was nothing!" she exclaimed.

"Alright well…I'm gonna go downstairs so…just…maybe don't scream each other's names next time?" Edwin asked. Derek grabbed the nearest small object and threw it at Edwin.

"Out!" he called out. Edwin ducked and then shut the door behind him. Derek turned to look at Casey who looked…horrified. He remembered hearing about how animals could sense natural disasters before they happened…well…he could sense Casey meltdowns before they happened and this was going to be a catastrophe.

"Casey," he said with a sigh. She turned to look at him and he kind of wanted to die when he saw the look on her face. Well maybe not die…but it fucking hurt. Because she looked horrified…at him.

"Do you think he'll tell anyone?" she asked in a very quiet, scared tone.

"Probably not. I'll talk to him," Derek said, getting up and pulling his boxers back on.

"But even still, he could tell someone. He cannot tell anyone, Derek!" she exclaimed. He saw her eyes start to get shiny and fucking damn it- tears were still hard for him to do. Especially tears over the thought of people finding out about them. If there even was a them. Apparently there wasn't.

"I just told you, I'll talk to him. Calm down," he mumbled and then instantly regretted it. Telling Casey to calm down was like waving a red flag in front of a bull.

"Do not tell me to calm down!" she exclaimed, picking his pants up off the floor and throwing them at him. He caught them and pulled them on.

"I just think…I mean would it be that bad?" Derek asked. She laughed a cold, humorless laugh and threw her hands up in the air.

"Would it be that bad? We cannot destroy our family for…random sex, Der-ek!" she exclaimed. Derek frowned. He'd had random sex before. THAT was not random sex.

"It's not random, we know each other!" he retorted. He knew it was lame but it was all he had.

"Whatever! Look, please just go talk to him. Convince him not to tell anyone, please?" she asked, giving him accidental puppy dog eyes.

"I will," Derek grumbled. Casey sniffled and wiped her eyes.

"Thank you," was all she said and rather curtly at that. Derek reached out to try and pull her into a hug but she crossed her arms and shied away from him. It stung worse than he had ever imagined anything could sting ever.

"I'll see you downstairs," he said quietly and didn't wait for a response before turning and walking out of the room. As he closed the door behind him, he heard her start to cry.

….

When he got downstairs, Edwin was sitting at the table with Marti and Lizzie, the three of them eating cereal and engaged in conversation. It seemed like no one but Edwin had heard anything so Derek sat down and tried to seem nonchalant.

"Morning, Smerek!" Marti chimed. He smiled at her and then glanced at Lizzie who was looking at him like she was trying to read him. She definitely knew.

"Morning, Smarti! How'd ya sleep?" he asked. Edwin and Lizzie were both burning a hole in him with the way they were looking at him so he just kept his focus on Marti.

"Good!" she replied simply and then went back to her cereal. There was a lull in the conversation before Lizzie and Edwin started making small talk again. Derek kept glancing at the stairs hoping Casey would come down but she didn't. It felt like forever passed before he cleared his throat and tried to look at Edwin casually.

"Casey's got this massive shopping list of things she needs before she leaves. I was thinking divide and conquer would be the best strategy," he said. Edwin looked at him strangely.

"Okay?" came his brother's reply.

"I was thinking you could come with me to the store," Derek said. The subdued way in which he was speaking felt strange to him.

"Oh um…that's okay, I'll just stay here," Edwin said, looking at Lizzie like he was begging for help.

"Nah, I insist," Derek replied, clapping Edwin on the back. Edwin jumped a little and relented.

"Okay. Sure. Sounds great," he replied, and then was uncharacteristically quiet for the rest of breakfast.

…..

When Derek and Edwin left an hour later, Casey had still not come downstairs. When he'd gone back up to get ready she wasn't in his room and the door to hers was closed. He tried to knock but she didn't even answer. This morning was very rapidly losing its "best morning of his life" title.

The two Venturi boys drove in silence, and Derek had zero clue what to say. He didn't talk about feelings. And even though it may have been a liiiiiiiittle funny, Edwin walking in on him and Casey was awkward. He was relieved when it was Ed that finally spoke first.

"So…are you actually taking me out to the woods to murder me, since I know too much?" Ed joked…although he did sound nervous.

"Do you know too much?" Derek asked. Because maybe he didn't. Maybe he-

"I know that I heard you and Casey having really loud sex this morning," Edwin replied. Okay, so he did.

"Okay…" Derek said, because he couldn't think of anything else to say.

"Okay?" Edwin exclaimed. He said it so loudly that it actually made Derek jump. He looked over at his brother, confused.

"Okay," Derek repeated again, this time louder.

"You're not even going to try and deny it?" Edwin asked, sounding almost as frantic as Casey had for some reason.

"Why would I deny it?" Derek asked.

"I don't know. Maybe because she's our step sister? Maybe because you guys hate each other?" Edwin asked. Derek rolled his eyes.

"You just told me you heard us. And ya sure felt fine walking in this morning, so denying it seems pretty pointless," he shot back.

"Dude…it's Casey. What are you doing?" Edwin asked slowly, as if he thought Derek was suffering major head trauma. Maybe he was. Because when Edwin said "it's Casey", he'd meant it in a bad way. And when Derek thought "it's Casey" it had a whole other meaning. Derek opened his mouth to respond, but nothing came out because he had no idea what the fuck he was doing.

"I mean Casey is…she's Casey! Ya know? She's like an old lady in a young person's body. She's…sensitive. She cries like all the time. And you're…you. New girl every month. Back to back dates. You can't-" Derek cut him off.

"I can't what?" he asked defensively. He glanced over at Edwin who was looking at him bug eyed.

"Bro…do you like…have…feelings…for Casey?" Ed asked. Derek let out a strangled laugh because what else could he do?

"I don't do feelings," was the only thing he could come up with to say. So he did.

"Yeah but-" Edwin started to argue.

"Look! I did not bring you with me to discuss…feelings," Derek put on a theatrical shudder, "I brought you with me to tell you that you cannot tell dad and Nora about this,".

Edwin gaped at him.

"You think I would tell dad and Nora about this? I don't even want to know about this!" Edwin replied, shuddering.

"No, I don't. But Casey thinks you'll tell them and she's freaking out so just…promise me you won't say anything?" Derek asked. And even though he hated sounding like he was begging, he gave Edwin the most earnest look he could muster.

Edwin looked back at him, uneasily.

"O-okay. Yeah. I won't say anything. Promise," he replied, taken aback by the fact that Derek didn't seem in control for once. Derek sighed and nodded once.

"Cool. Thanks," he said. Edwin nodded.

"Anytime," he replied. There was an awkward pause, as neither of them knew what to say. Afterall, they didn't do feelings.

"I do reserve the right to use this as blackmail at any point in the future though," Edwin said. Derek was about to use his big brother power to scare that thought right out of Edwin's head but after glancing over at him, he realized Ed was just trying to lighten the mood.

"Fair enough. Just don't say that around Casey"

….

When they got back from the grocery store with all the things Casey had written down, she was nowhere to be found.

"Where's Casey?" he asked Lizzie, after putting away everything they had bought.

"She went shopping with Emily. They took Marti with them," Lizzie replied. Derek hoped he didn't look as disappointed as he felt and then cursed himself for being so whipped.

"I'm gonna take a nap," he mumbled and started out of the kitchen.

"Derek?" Lizzie asked, following him to the bottom of the stairs. He turned to look at her.

"Just um…just don't…just be nice to her," Lizzie said quietly. He was shocked at her bringing it up so brazenly but it made sense. Even though Casey was older, Lizzie was always the level headed one and he saw how much she tried to protect her older sister. He'd never admit it before but he always thought it was nice that someone was always watching out for Casey. Well…someone other than him. But he'd had to be sneaky about it. He didn't know what to say so he just nodded once and then took off up the stairs.

When he reached his room, he shut the door behind him and flopped down onto the bed. It still smelled like her and he felt a knot in his throat. It wasn't fair. It wasn't fair that he'd managed to make it literal years without his feelings for her becoming a problem and now that they were going to be thousands of miles apart, he was getting all sappy. Derek Venturi was not a sap. He wasn't going to be one of those guys he made fun of for getting all romantic over some girl. Except it wasn't some girl, it was Casey.

As he drifted off, it occurred to him that neither Lizzie or Edwin seemed surprised. And that meant something…right? He'd have to remember to point it out to Casey later tonight, when they were inevitably going to fight about it.