Disclaimer: I do not own Life with Derek, obviously.

Never be the Same

Casey could feel the beat pounding in her chest as she and Emily stood outside the doors of The Unseen, the new club that had just opened up. Once a week they had an all-ages night and Emily had been begging her to go for the past month. Casey always made excuses about why she couldn't go, but she had finally given in on the weekend and told Emily that they could go on the following Thursday. Emily had thought that it had been her constant badgering that had finally gotten Casey to cave, but the truth was, it was all because of Derek.

Casey walked into the house and was pleasantly surprised to find it empty. Normally, she would not mind the company of her family, but she had just gotten into a big fight with Max and she was glad to have the time alone to think. After making herself a snack she decided to just sit down and watch some TV until she was calm enough to think things though rationally.

Of course, her peace was short lived. About 10 minutes after Casey had started watching a show, Derek had walked in the house and flopped down onto his chair, stealing the remote in the process.

"Excuse me, I was watching that," Casey said as Derek began channel surfing.

"You're excused. It's my turn with the TV."

"God Derek, I've had a really bad day and I would just like to have a little time to relax and calm down. Can't you think of someone else's feelings for once in your life?"

"Oh right. I heard about your fight with Max. You really should just dump the guy. I mean, he plays football," Derek said, practically shuddering at having to utter the word 'football'. "You guys have next to nothing in common and you always fight. You know, no one would judge you for dumping him."

"What is that supposed to mean?" Casey asked, unable to keep the shock out of her voice.

"I think you know exactly what it means," Derek replied. At Casey questioning raised eyebrow, he continued, "Can you honestly tell me that you don't do everything with the objective of making someone else happy? The good grades, the volunteer work, dating Max? All of it is for someone else."

"All of those things make me happy," even as Casey was speaking she was beginning to wonder if maybe Derek was right. Sure, all of those things made her happy, but was she always doing them to please everyone else as well?

"When was the last time you did something you wanted to? Just because it would be fun, regardless of what anyone else wanted or thought."

Casey couldn't help but just stare at Derek, when had he become so insightful? And when did he actually start caring about what she did? She looked up to see him staring over at her. Realizing he was expecting a response she opened her mouth to speak, "I… I don't know."

So here she was, five days later, standing outside a club with Emily because she wanted to have fun. She wanted to do something for herself. Sure, Emily had been eager to come, so Derek may argue that she was still just doing it to make Emily happy, but that wasn't the truth at all. Casey wanted nothing more than to be here, in this moment, not caring about anything but what she wanted.

--

Derek sat on a stood at the bar watching the door. He knew that Casey and Emily were planning on coming tonight, but he would not believe it until he saw it. He expected they would get half way to the club before Casey would chicken out and run back home. He was shocked when he saw Emily walk in wearing a short, pink dress, but his jaw nearly hit the floor when he saw that she was being followed by Casey, who was dressed in a low-cut V-neck halter top which showed a fair amount of cleavage and a short black skirt. The thing that Derek noticed most was the look on her face, he was expecting to see her embarrassed or scared, but her face showed nothing but pure joy. She had a huge smile on her face and Derek had never seen her look more carefree or more beautiful.

Casey and Emily were slowly making their way towards the bar, stopping to talk to various people they knew, all of whom seemed just as shocked as Derek was to see Casey there, and Derek noticed that a large number of guys were checking Casey out, but he wasn't really surprised.

Derek's attention was pulled away from Casey as a blonde girl walked up and asked him to dance, placing her hand seductively on his arm. Normally, she would be just the type he would go for, but tonight he just wasn't interested. The girl turned and walked away in a huff after Derek told her he didn't dance.

Derek turned around just as Casey and Emily reached the bar. "Fancy seeing you here," he said to Casey, his classic smirk in place. "And without Max. I'm shocked."

"Yeah, well someone told me I should get out and have some fun. I told Max that we should spend the night separately."

"Casey, I'm going to go dance. You're okay here, right?" Casey heard Emily, she turned to see a really hot guy standing next to Emily. "Yeah, I'll be fine. Go. Have fun," turning back to Derek, Casey smiled, "Five minutes and I have already been abandoned."

"You don't seem to upset about it," Derek smiled.

"I'm here to have fun, I'm not going to worry about being alone, Emily can have a good time, too. I am going to have a drink and then I am going to find someone to dance with." "Wow, I think I like this new Casey. Maybe, if you were like this more often we would get along better."

"Yes, because our fighting is all my fault. You are such a perfect angel,"

"I know, it's nice of you to admit it, though,"

Casey was prevented from retorting as the bartender came over.

"What can I get you two," She asked flirtatiously, taking a moment to check Derek out. Typical, Casey thought.

"Two vodka sevens," Derek replied. Casey turned to look at him with a shocked expression.

"Derek, we are not old enough to drink. She shouldn't even be serving us alcohol, I thought these nights were alcohol free."

"Casey, Casey, Casey. So young, so naïve. Just drink it and enjoy my generosity. It will help you have even more fun."

"I do not need alcohol to have fun." Derek just raised an eyebrow in response, telling her that he would never believe that. "I don't," she continued. "I have plenty of fun."

"Sure you do. But whatever, I understand if you don't want to, I mean, what would your mother think?" Casey knew exactly what Derek was doing, and that she shouldn't give into his antics, however, when their drinks arrived she could not stop herself from raising the glass to her lips and taking a long drink. Derek laughed, although weather it was at his triumph or the face that Casey made, she wasn't sure.

"I take it you've never drank before. What am I saying? Of course you haven't. You might want to take it slowly, it can hit you pretty hard the first time. One day I will tell you about my first time drinking. It was not my finest hour, I'll tell you that."

Derek and Casey continued sitting at the bar and just talking for the next hour. Neither of them had realized how much time had passed until a song came on that Casey had to dance to. She stood up a little unsteadily. She had only had two drinks, but since it was her first time she was affected quite a lot. Derek, having started drinking before Casey had even arrived was also starting to feel it, but not quite as much as Casey. But enough that, despite his no dancing policy, he went with Casey when she pulled him off his stool.

As the beat to Kat Deluna's Whine Up pounded through the speakers Casey began to sway. It took her a few seconds to find her rhythm and when she did Derek could do nothing but just stand and stare at her, she was absolutely mesmerizing. He had seen her dancing at her ballet recitals and things like that, but seeing her like this was a totally new experience for him. She looked so carefree, her smile was contagious.

Derek also started moving to the beat, once he realized that he probably looked like an idiot as the only stationary person in a sea of moving bodies. Somehow, he and Casey had managed to end up near the middle of the crowd, so he was less self-conscious about his dancing ability, or lack thereof.

Derek was paralyzed with shock when, about half-way through the song, Casey moved put her hand on his shoulders and started grinding against him. He started to move along with her, deciding that he didn't care that she was his step-sister or that she had a boyfriend, he was just going to enjoy the feeling of her body against his.

Casey could not believe what she was doing, she was just having so much fun. She knew that the idea of grinding with Derek should be repulsive to her, but it was not. It was probably just the alcohol talking, but for tonight, she didn't care. Suddenly, the thought of Max popped into her head. He never made her feel like this, so alive, so happy, and in that moment she knew. She knew that Derek was right, she should spend less time doing what people wanted, she should do whatever made her happy. As long as she wasn't hurting anybody, what others thought didn't matter. She knew that she had to break up with Max. She was mostly shocked to realize that it didn't upset her at all. She would talk to him tomorrow, and tonight she would just enjoy herself.

A new song came on and Casey looked up at Derek to see if he was going to leave, but he just smiled down at her and continued dancing. Felling brave, Casey pressed a kiss to the side of Derek's neck before turning around and pressing her back against him. She shivered as she felt his breath on her ear just before he whispered huskily, "If dancing was always like this, I would do it a lot more often." She felt his lips against her neck as his hands slid down her thighs. She just leaned into him more. Tilting her head to the side to give him better access.

Casey didn't care that everyone could see them, or that, by Monday, everyone would be talking about it. Quickly, she spun around to face Derek, before he could say anything she pulled his head down and met his lips with hers. She moaned as Derek pulled her flush against his body and ran his tongue across her bottom lip, begging her to open her mouth to him. She, of course, complied, marveling at the feeling of his tongue sliding against hers as she slide her hands up to play with his hair.

Pulling away from him, Casey looked up at Derek and as he opened his eyes she saw a look of pure lust, a look that she was sure was reflected in her own eyes, "Let's get out of here." Derek's eyes widened slightly before he nodded, pulling her from the dance floor and towards the door.

On the way out they passed Emily, who was still dancing with the same guy she had left with earlier in the night.

"Where are you going?" She asked as Casey and Derek approached her. Derek had let go of Casey's hand by this time as to not cause any suspicion on Emily's part. She was Casey's best friend, but she was also the biggest gossip at their high school. Not to mention, she had liked Derek forever.

"I'm really not feeling well, I have a bit of a headache, Derek is going to take me home," Casey lied, probably the most convincingly Derek had ever seen her lie. When Emily looked like she was about to tell the guy she was dancing with that she had to leave, Casey continued, "You stay though, I want you to have a good time. I will call you tomorrow, okay."

"Are you sure?"

"Yes, I'll be fine. Have fun." With that Casey turned and continued to walk towards the door with Derek. Once they made it outside and were finally alone, Derek pushed Casey up against the wall and started kissing her neck again. Though they were in a secluded, dark area, Casey still felt exposed and once Derek began moving his mouth lower, along the neck line of her shirt she had to push him away.

"Not here," And so Derek got them a cab and they rode home. The ride was short and Derek held her hand the whole ride, like he was afraid that if he let go Casey would change her mind.

They pulled up outside of their house and saw that it was completely dark, suggesting that everyone was already in bed. And although neither of them said it out loud, they were both very happy about it.

As Derek stood on the porch trying to unlock the door and fumbling with his keys, Casey pushed herself up against his back and started kissing along his neck, wrapping her arm around him and rubbing his crotch.

"If you keep doing that I am never going to get this door open," Derek said, his voice strained and full of desire.

"Then I guess you will just have to keep me warm out here all night,"

"I don't know what has gotten into you, but I really hope it doesn't change," Derek replied, finally pushing the door open and pulling Casey inside.

Once they were both inside and the door was shut behind them Casey gave Derek a quickly peck on the lips, saying, "Thanks, I had a lot of fun tonight," before running up the stairs, leaving Derek standing dumbfounded at the door.

He stood there for a few minutes trying to figure out what happened before walking up the stairs, he noticed that Casey's door was closed. He knocked, but there was no answer. Walking to his room, he opened the door and saw Casey sitting on his bed, smiling innocently up at him.

"Took you long enough, you are lucky I didn't just get bored and go to sleep,"

"You…" Derek didn't even know what he was going to say, deciding not to say anything he just walked over to his bed, pushed Casey down so she was lying on her back and climbed on the bed, one knee on either side of her thighs he leaned down to capture his mouth with hers.

Their kisses were full of passion and urgency, neither wanting to take the time to think about the consequences of their actions, just enjoying the feeling of being so close to one another.

Derek moved his hands from Casey's face down her body, stopping for a brief moment to grab Casey's breast. In response she arched her back up into him and ground her hips against his. Derek groaned at the feeling.

Taking advantage of Derek's moment of distraction, Casey quickly flipped them over so that she was on top of Derek, between his legs. She moved her hands under his shirt to feel his tight abs and strong chest. She took a second to reposition herself, so that she was straddling Derek before pulling the shirt up over his head and throwing it to the floor.

In response Derek pulled off her shirt, revealing a lacey red bra. Derek smiled, knowing he would never be able to forget the image of her wearing that bra, straddling his hips which caused her skirt to ride up enough that he could see she was wearing matching underwear. Slowly, Casey moved down Derek, placing small kisses down his chest and stomach, all the way down to the waist band of his jeans where she stopped. Agonizingly slowly she undid his belt and unbuttoned his jeans, sliding them down his legs, along with his boxers. He looked at her questioningly when she got up to stand at the end of his bed. She just smiled at him. She dropped his jeans and then wiggled out of her own skirt, standing before him in her bra and underwear. "God, you are beautiful," Derek said as he looked her up and down. He knew that she wasn't a virgin. She and Max had been together for almost a year and he had found condoms in her room one day when he was snooping, but he still hadn't expected her to be so confident. He was expecting shy, grade-grubbing Casey. This was so much better, it made him want her so much more. He was already becoming painfully hard, and staring at her standing in front of him with the only light coming from the streetlight outside his window was making it even worse. She slowly removed her bra and panties before climbing back onto the bed beside him.

Derek wasn't sure what she was going to do, but he was unwilling to wait for her to make the next move. He wanted her, so he pulled her close to him and kissed her hard, pouring all of his desire into the kiss. Casey rolled them over so that she was on top of Derek, reaching over to his bedside table and pulling a condom out of the drawer. She ripped it open and placed the tip between her lips. Derek gave her a confused look, she just responded by winking and sliding down his body.

Derek gasped when he felt her lips on the tip of his penis. Using her lips and tongue she expertly slid the condom down, taking him fully in her mouth. Derek really wondered where she had learnt that trick, it was definitely something he had not experienced. Casey was definitely giving meaning to the phrase, 'lady in the street, but a freak in the bed'. She slide her mouth up and down a couple more times before kissing her way back up Derek's body and capturing his mouth in a searing kiss.

With just the feeling of her body against his, Derek knew he wouldn't be able to hold on much longer so he quickly flipped Casey over and slid into her. Both of them moaning at the feeling.

--

Hours later Derek woke up when he felt Casey stirring beside him. She quickly kissed him on the lips and smiled before sliding out of the bed. Before she could get all the way out Derek pulled her back to him and kissed her hard, sliding his tongue into her mouth. He was shocked that Casey kissed him back, but it ended far to quickly as she pushed him away, grabbing her clothes and rushing into her room.

Derek lay awake for a long time after Casey left, he didn't know where they stood now. He didn't have any idea what he wanted and he definitely didn't know what Casey wanted, technically, she was still with Max. He knew that the next day she would probably be freaking out and completely overreacting.

The one thing he knew for sure was that things between them would never be the same again.

The End, maybe.

A/N: This is my first Life with Derek story, any feedback would be greatly appreciated. I am not sure if I want this to by more than just a oneshot. It will depend on what the readers want, so if you want it to continue, let me know.