Author's Note: Thanks for the reviews! This chapter I tried to get into Casey's real emotional side, the side she doesn't show very much... I hope it came out alright... please leave feedback, I'd totally appreciate it!

Casey spent most of the night in her bedroom, crying silently in the dark. She had left her clothes in Derek's bedroom in her rush to get out of there once he had fallen asleep, and she took a scolding hot shower to wash away every trace of him. Of them. Of what they had done. Of the sin that they had committed.

She couldn't believe she had given her precious virginity to her player asshole of a stepbrother. Who had had more girls than he could ever remember. And she herself had a boyfriend. A sweet, kind boyfriend who she had just cheated on with his best-friend.

She cried until there were no more tears left, and fell asleep in a mess of exhaustion.

"Casey?"

She opened one eye and looked over to see Lizzie at her doorway, peering in on her with a concerned look on her face. "Are you okay? You've been sleeping all day."

Casey blinked several times. "Wh-what time is it?" she asked groggily.

"Three in the afternoon," Lizzie responded, cocking her head to the side. She knew that her sister was never one to sleep in later than 10AM. "Are you okay?" she repeated, taking note of her sisters puffy, swollen eyes.

"I'm fine," Casey said, sitting up on her bed. She let out a yawn, thinking about what a horrible nightmare she had had, and got up to show Lizzie that she was just fine. But as she walked over to the other side of her bed, she let out a gasp. Her inner thighs ached and she had that dirty feeling wash over her.

"Oh my God," she murmured, sinking to the floor instantly. It hadn't been a nightmare.

"Casey!" Lizzie yelped, rushing over to help her sister. "What's wrong?"

Casey let Lizzie help her up, and tried to regain her composure. "N-nothing. I just got up too fast, that's all," she made up quickly.

Lizzie didn't look all that convinced, but let it go. "Mom and George went off to some art exhibit a few hours ago," she relayed. "Edwin and I are in charge of Marti."

"Where's Derek?" the words rolled off Casey's tongue before she could stop them.

Lizzie shrugged. "Out with his friends I guess. Or a girl," she rolled her eyes.

Probably telling all of his friends how he had his own stepsister last night, Casey thought bitterly to herself. Probably telling them that I'm an easy lay. Damn that Derek Venturi!

Lizzie watched the mixed emotions move over her older sister's face and her eyebrows furrowed. "Are you sure you're okay, Casey?"

"I'm fine," Casey feigned a smile. "Let me get dressed and I'll be downstairs in a few minutes, okay kiddo?"

"Sure," Lizzie said slowly, and turned to leave. And report to Edwin that Casey was acting weird for some reason.

Casey went into the bathroom and scrubbed her face as if to rid the memories of last night completely from her mind. She didn't bother with any make-up, and just pulled her hair up into a tangled, messy ponytail and changed into sweatpants and a tank-top. Lounging Sunday clothes.

Morning After a Big Mistake clothes.

"I made you a peanut butter a jelly sandwich," Lizzie said as Casey walked downstairs into the living room. "Smooth peanut butter and strawberry jelly. It's in the kitchen."

"Aww, thanks, Lizzie," Casey forced a smile at her younger sister. She was such a sweet girl, always looking after her older sister. She ate the sandwich and washed it down with some milk, and read a magazine to take her mind off of Derek. It was working, and Casey felt her spirits being lifted as she walked into the living room again to see what her younger siblings were up to.

"Casey, wanna play Operation with us?" Marti exclaimed from where Edwin and Lizzie were helping her set up the game.

"Sure," Casey smiled a genuine smile, and sat down around the board with the others. Just as she was starting to get into the game, the door opened and Derek walked in, dragging his huge hockey bag in with him.

Casey's breath caught and stomach lurched as her eyes met Derek's. A slow smirk formed across his face and Casey blanched, suddenly wishing she hadn't eaten that sandwich.

"Smerek!" Marti shouted, jumping up and running over to him. Casey watched as Derek lifted the squirming little girl up into his arms and Marti squealed in delight as he tickled her.

"Excuse me," Casey said to nobody and she ran upstairs, quickly shutting her bedroom door behind her. She sat down at her computer, hugging herself and taking deep breaths to relax. She couldn't face him. She didn't want to. Not after they had… done it. He had seen her naked. He had done things to her that she had never let Sam even attempt. Hell, he had been inside of her.

She got nauseous at the thought.

Her cell phone rang and she jumped at the shrill sound. "Relax, Casey," she told herself, grabbing her cell phone off of the desk. "Hello?"

"Hey, Casey."

It was Sam.

"Oh, Sam, hi," Casey tripped over her words. "Um, how was practice?"

"Long," Sam chuckled. "What have you been up to today?"

Just listening to his voice, Casey felt overcome with guilt. She was a dirty, rotten person. A cheating, lying slut. "Not much," she said weakly, her stomach turning. "

"You feel up to catching a movie or something?" he asked.

Casey felt her heart clench at the innocence of his question. He was asking her out. Just hours after she had had sex with his best-friend. "Um, I, uh, can't," Casey replied, feeling horrible. "It's just… I've got this French paper to finish up and a history test to study for."

"Oh," Sam sounded disappointed. "Well, that's okay, maybe later this week or something."

"Yeah," Casey said half-heartedly. She heard her door creak open and her eyes widened into saucers as she found Derek at the doorway.

"Uh, I, uh, gotta get going," she said quickly to Sam. "I'll see you in school tomorrow."

"Alright," Sam said. "Goodnight, Casey."

Casey felt her heart tearing. "Goodnight, Sam." She hung up and glared up at Derek.

"Having a heart-to-heart with Sammy Boy?" Derek asked, coming into the room without permission and closing the door behind him.

"What do you want, Derek?" she kept her eyes narrowed and teeth gritted.

"A repeat of last night," he said offhandedly, as if it was No Big Deal. He gave her a trademark Derek smirk and sat back on her bed.

Casey's jaw dropped open. "Derek last night was a stupid, stupid mistake. And there will NEVER be a repeat, you got that!" she exclaimed, jumping up from her seat. "We're going to pretend that it NEVER happened and—"

"But it did happen," Derek interrupted her smugly. "We had sex, Casey, whether you admit it or not."

"NO!" Casey screamed, not wanting to hear it. Not wanting it to be true.

"Yes!" Derek exclaimed, leaping up from the bed and grabbing her by the shoulders. "Casey, you and I slept together last night. We slept together," he told her slowly and forcefully.

"No," Casey protested weakly, feeling a tear splash down her face. "It's not true. It's not true." She felt the tears begin to flow now, and her knees buckled. Derek caught her easily, his face surprised at her reaction. He gently brought her over to her bed and let her lay down. He got into bed with her and wrapped his arms around her as she cried, his face priceless as he didn't know what to do with the crying girl. He awkwardly stroked her hair and back, letting her sob into his shirt.

Derek didn't know how long she cried for or what he cooed into her ear, but it took quite awhile for her sobs to subside into small hiccups.

He almost jumped when he heard her speak.

"I wasn't exactly planning on having a white wedding," she said quietly. "I wasn't saving myself for marriage or anything. I was just… waiting for true love," she admitted.

Despite himself, Derek felt bad for her. Even though the sex had been completely consensual, he felt like he had done something terrible by taking his stepsister's virginity away from her.

"That's why I didn't want to believe it," Casey continued in her soft, breathy voice, raspy from her sobs. And she closed her eyes, succumbing to the exhaustion she had worked herself up into.

Leaving Derek alone with his thoughts.

He was finally beginning to see it. See that life wasn't just fun and games. Actions had consequences.

And consequences were hardly fun.

He looked down at Casey. Her eyes were practically swollen shut, and there were dried tear tracks on her face. Her lips were contorted into a sad frown, and her forehead was slightly wrinkled. She obviously wasn't getting any real rest in her sleep. Gently, he ran his hand over her forehead. It relaxed a bit, which made Derek feel better.

"I'm sorry, Case," he whispered, pressing a gentle kiss on her frowning pink lips. He was sorry for sleeping with her, even if he had enjoyed every single second of it. Sorry for hating every moment she spent with Sam. Sorry for wanting her so badly.

And now, sorry that he was starting to fall in love with her.