Disclaimer: I do not own any original Life With Derek characters that may appear in this story.

Claimer: The remainder of this story including: plot, dialogue, & OC characters, is my original work.

No copying or reproduction of this work is permitted without my express written authorization.

Author: softasthunder

You Know - Life with Derek Fanfiction

You know that she wants a grey kitten with green eyes because she's always begging Nora for one; "But Mum, please, just—"

"No, Casey, you know George is allergic to cats!" Her tone is firm, and you know that Nora isn't backing down on this one.

You mentally groan, just great, this is just another reason for her to hate you and you know that the only thing to make her happy would get you in even more trouble and you can't really get in more trouble than you are now, especially now that your dad and Nora know what you've done. You're in enough deep, boiling water for sneaking that girl—what was her name again, Isabella, Lindsay? You don't remember, all you can think of was that she had dark blue eyes and her hair was silky and dark and just, just so, so—in and fucking her.

"But Mum you promised me that would get me one!" You hear the small waver in her voice, and you know that Nora doesn't. You kind of want to yell at her for hurting Casey like this.

"That was a year ago, Casey, and besides you are living with your new family and you must respect your new father—" But you can basically hear Casey's eyebrows rise when Nora calls your dad her father. You wonder what the fuck is going on in her head. She definitely can't be Casey's mum, no fucking way.

"Casey, I didn't mean i—" But you know she's walking away, and you don't even want to think of how much she probably hates Nora and George at the moment.

She avoids everyone during the weekend and goes out every day after school for two months. You know that your family is hurt, but at the same time, you hate them too, just for pissing Casey off and making her ignore you.

-D-

It's two AM and it's pretty fucking insane about what you're doing right now, but you still do it anyway because you've finally accepted that you're in love with Casey McDonald. Yes, Casey McDonald who also happens to be you're step-sister.

So you're walking to both of your apartment that your dad and Nora made you share because it's cheaper, and the wind is really harsh and cold tonight so you pull the thing closer and let it snuggle up against you; pulling your jacket tighter around yourself you fumble around for your keys but the door is flying open and there is Casey with chapped lips that you can just tell she's been gnawing on, and she's dragging you inside and you know she's about to go ape shit on your ass.

Suddenly you thrust the thing at her and her expression is quickly one of shock, before it can process in her mind you're rambling.

"I just knew that you wanted one, and since we're living alone, and you know all adults and shit, so I just thought that you deserved it because well you're actually pretty, dare I say it, awesome especially now that you've loosened up and we're in University. So anyways I just knew that you liked it and always wanted one—just like that so—" but you're cut off when she throws her arms around you and hugs you the best hug you've ever had and presses a kiss close to your mouth and you know you're suddenly not imaging her blush.

"Thanks Derek, this is the best thing anyone has ever bought me." And she's cuddling that grey furred-green eyed creature close to her chest and avoiding your eyes but still grinning so big it looks like it's going to break her face.

You shrug modestly, because who are you to deter any good feelings she has for you? Next thing you know you're setting up her food while Casey shows her the litter box. When you both catch each other eyes you grin, and because you're bed isn't that comfy—and you both know that—she offers to share her bed with you.

You accept and soon, you're making excuses to be there every night.

Neither one of you has said anything about it.

-D-

A few months after the cat incident, which she named Matrix, you feel something on top of you. Blinking your eyes awake you're confused as to why Casey is leaning on top of you.

"Uh, Case?" You ask hesitantly.

You see this does not have any effect on her expect for receiving her brilliant smile.

This only confuses you more. And slightly scares you, because usually when Casey smiles at you, it means a lot of pain.

"I was just bringing you some pancakes." She gestures to the night stand and you see a thick stack of beautiful pancakes, drowned in syrup.

You immediately start to slaughter the pancakes, and thank God Casey is simply amazing when it comes to pancakes.

"Why?" You ask after swallowing a large piece. You see her still look at disgust with your eating habits, but you can also see her affection.

She absent mindedly wipes a tear of syrup for the corner of your mouth; "Just saying thanks." She gets up, not after planting a kiss on your cheek, and leaves.

Then you remember that you helped her study for her math exam and suddenly you're grinning because thank God you're amazing with math otherwise you wouldn't get this special treatment.