Ok, so while I was watching the last 2 episodes of season 4, I got an idea, changing a "little" bit episode 69, Surprise.

Here, Casey never asks Emily, because Emily was going with her boyfriend since she never broke up with him; and Truman didn't try to go after Casey once again and she never gave him a second chance.

Same Thing

It's the night before the prom, everyone were already sleeping, except Casey who couldn't find a date to the prom in time, so she was too sad to just fall asleep. Feeling the need to eat something, anything; she got out of her bed and walked downstairs to the kitchen. She turned the lights on, just to surprise herself with Derek, eating a sandwich.

"Derek, what are you doing here?"

"Eating sandwich?" He answered with his usual sarcasm.

"I meant why the lights were off?"

"I just didn't bother to turn it on, it could wake up someone"

"Ok, one, our brothers and sisters are upstairs; two, our parents are downstairs; and three, you don't care about the others"

She said in the usual methodical way she speaks, grabbing a bowl and disposing cereal in it, then she got milk inside the fridge, pouring the white liquid on the cereal. Just like she does almost every morning.

"So, maybe I just wanted to think with the lights off, that's all, you don't need to be so boring over it" He answered "And why are eating it at night?"

"Cause I want it, that's all" She replied the same way, starting to eat the cereal on her bowl. There was a minute or two of silence, until Derek breaks it.

"So, did you have any date to the prom tomorrow night?" He asked with his mouth full of sandwich.

"Gross…" She replied at first, rolling her eyes, sighing, she answered. "No, so I'm not going. Did you?"

"Nops. I can't believe all the girls I asked dumped me"

"Well, looks like we're in the same boat"

"No way. I'm still going; I've got to find a date till tomorrow night. But I bet you can't"

"First, I don't want to bet with you; second, I already decided that I won't go"

"Too bad"

He told her right before putting the rest of the sandwich inside his mouth and getting out of the kitchen going upstairs before she had time enough to yell at him for not cleaning up the things he used to make his sandwich. Casey sighed, she knew it was just too late now; she did it herself.

The next day, Derek still couldn't find any date to go with him to the prom, and it was starting to make him crazy, after all, he is Derek Venturi, he couldn't go to the last prom of High School without a date. He was getting desperate.

Then, it hit him. He could go with Casey. Ok, so she's his step-sister, but she was a girl who just broke up with her jerk boyfriend, and being who he is, he'd do her a favor if they went together, since his the most popular guy in school and couldn't let his "sister" go alone. Right?

At night, he put on a wonderful black tuxedo (Author's Note: I know in the show he didn't use it, but I really rather him with it) and at the moment Lizzie and Marti went out of her room after a girls talk, he entered, obviously, not knocking.

"Have you ever heard about the word knock?" She asked him eating popcorn, sitting all alone on her bed at the night of the prom.

"No, I haven't" He told her playfully, she rolled her eyes "And before you ask me what I'm doing here, I'll ask why aren't you ready?"

"Are you crazy? I'm not going, I told you. I don't have a date and I don't want to go without someone"

"And that's where you're mistaken. I got a date for you"

She sat up straight on her bed, feeling confused yet anxious.

"Who?"

He didn't answer, just moved his hands in a you're-looking-at-it way. Her anxious part quickly faded in a glare. She sighed.

"Come on Derek, I can't go with you and I know you too well to know that you don't want to go with me"

"You're talking too much, it's confusing me. Just go get changed and let's go"

"Are you really that desperate?"

Being who he is, he couldn't just admit it, so he lied.

"Of course not, I just thought that I can't live you here at our prom when both of us didn't get a date. I'm just being unselfish"

"Derek, unselfish is just the oxymoron of you"

"Oxy what? Well, whatever. I just want to take my sister to the prom, that's all"

"Step-sister"

He shrugged.

"Yeah. Whatever. Same thing… Now, will you go or not?"

"I told you that I'm not going"

"Ok then, stay here eating popcorn, when you turn old you'll regret it every single day"

Derek told her in a serious tone and walked out of her room, slowly. Casey could picture herself all alone in a room crying and regretting not going to that prom. She freaked out and ran to the door, finding Derek walking towards the stairs, she didn't see, but he was counting the seconds it took her to call his name, and when she did it, he smiled before turning around asking:

"What?"

"Ok, I'll go, wait me downstairs; it will only take a minute"

"Sure"

He turned and headed downstairs, a triumphant smile on his lips. I always get what I want, he told himself. Meanwhile, Casey called her mother to help her get dressed. However, it didn't take a minute like she said, it never does, it just takes a lot of minutes for girls to get dressed to a prom: makeup, jewels, dress, and hair. Everything takes time.

Derek was almost sleeping on the couch, waiting for her, almost regretting asking her and going by himself. But then, Nora walked downstairs in a rush, with a big smile on her face, announcing that Casey was ready and coming. He sighed in relief, standing up.

"Finally"

He replied moving his gaze to the stairs, where he found her slowly descending, her right hand firmly holding the handrail while the other one held her beautiful dark blue dress up, clumsy as she is, she'd probably fall. She stopped almost in the end of the stairs, at the part where the direction turns 90 degrees, towards the living room.

"So, how am I?"

She asked smiling, proud of herself. Her mother embraced her, telling she was beautiful. Derek didn't say anything, he was literally without words. He was so impressive by her that he almost let his jaw drop. George hit Derek on the back two times in a manly way, telling him.

"Derek, I'm proud of you for taking your sister to the prom instead of letting Casey spend the night here. And by the way you're beautiful"

"Thanks"

Derek just stood there without moving, just looking at her, amazed with the sight, but then something hit him, hard. The word sister. It never bothered him before, at least not that much. He had to remember himself that the amazing girl right in front of him is the daughter of the new wife of his father.

George pushed Derek, who didn't move by himself, towards the stairs, towards Casey. Derek took a deep sigh getting mentally ready to take his beautiful "sister" to the prom. She started to walk down the last steps of the stair, she was almost making it, however, Casey is just too clumsy, she tripped on her own feet and almost fell; actually, if it wasn't for Derek waiting by her side at the end of the stairs, she'd have fall.

There was a moment of silence. She gulped, looking at his deep chocolate brown eyes, while he looked at her blue sky eyes. He also gulped. Slowly, he managed to get his arms off her waist, since she was already on her feet. It was almost kinda awkward.

So, both of them got out. Nora turned to George with a confused look on her eyes.

"Is it just my imagination or there was something more in their eyes?"

"Oh, come on, Nora. They're siblings"

He told her, not really caring about it, then he walked towards the kitchen. Still puzzled, Nora rested her head on her hands after sitting on the couch. For some weird reason, it still bothered her. She wasn't really wrong at all.

At the prom, Derek and Casey were standing next each other, looking couples dance slow and romantic songs. It was killing Casey inside, tonight; she wanted to dance at least one song like that. But she couldn't ask Derek, right?

"So, Case, do you wanna dance with me?"

"What?" she couldn't believe what she heard.

"Well, you know, since I can't get anyone else, I'm stuck with you tonight"

She sighed

"Since I love those kinds of songs and I'm stuck with you… I guess I have no choice"

"Good. But I don't want anyone to see me with someone like you, so we're going to do it back there"

He said grabbing her hand, dragging her to somewhere a little less crowded, where anyone could see them easily. He wrapped her waist like he'd do with any other girl; she shyly put her arms around his neck. They started to dance at the rhythm of the song.

"Derek, just be honest, you just asked me out because anyone else accepted and you didn't want to go all by yourself, right?"

Lost in her blue, deep, dazzling eyes, he couldn't lie anymore.

"Yeah" she was surprised to get the answer so quickly "But I don't really regret it"

He gulped noticing he was talking too much. Derek tried to roll his eyes to break the eye contact with her, somehow, he just couldn't. Her eyes seemed brighter than the sun, yet more powerful than gravity that kept his feet on the floor. However, he wasn't the only one in trouble; she was as troubled as him, it was impossible to deviate her sight from his chocolate brown eyes.

"Me too…" She answered as honestly as him, unable to lie. "Thanks for bringing me here tonight"

His way to say "you welcome" for girls, usually is with a kiss, so he just started to lay towards her, closing his eyes in the process. Taken by the moment, she did the same, both hearts beating faster and faster. As simple as that, both lips met in a light kiss that quickly turned into something deeper. That is till she breaks the kiss up.

"I-I gotta go"

She said stuttering walking away. Her hand lightly pressed against her lips warmed by his owns. It was all too much for her to handle. He said they were only siblings, he was the one that always pushed her away, he was the one who never cared about her and now kissed her that way. But she didn't know that he never regret something so much than calling her just a sister. Because she never was and never will be. She's something different and he knows it. But maybe it's just too late.

I hope you all enjoyed it and please review! I'm not sure if I'll live it as a one-shot or if I'll continue, so please, if you want to read more, please review! I hope Derek and Casey didn't seem too Out Of Character, though...

Thanks for clicking and reading!

Itban Fuyu