A/N: VERY sorry I took so long to update! I had the first part written for the longest time but I couldn't figure out how to write the rest. I knew exactly what I wanted to happen, I just didn't know how to go about it. I thought about leaving you with just the first part, but I figured that would be too mean, since it was pretty short. Well, at any rate, I hope this chapter was worth the wait.

Oh, and I still love all the reviews! Thanks to everyone who sticks with me.

Disclaimer: I don't own Life With Derek.

Once inside, Casey didn't waste any time. Dodging Nora and Lizzie's questions, she sprinted upstairs and found herself in front of a closed door, behind which lay the source of all her confusion. Summoning all her courage, she knocked loudly on her eldest step-brother's bedroom door.

A few moments later it opened and Casey found herself face-to-face with Derek himself. He stood only a few inches taller than her, so their faces were nearly level. Derek's expression was unreadable. They were so close, Casey could feel the heat radiating from Derek's body. She felt a shiver go through her. Unable to contain herself any longer, she leaned forward and closed the distance between them.

After the usual spark of electricity ran through them, Casey felt herself relaxing into the familiarity of the kiss. One of Derek's hands rested on the small of her back, and she could feel the warmth through her thin sweater. His mouth was warm and soft and she couldn't get enough of his taste. No thoughts of Sam ran through her mind at all; she was simply caught up in the moment. Derek moved her inside, slammed his door shut and pressed her against the wall, kissing her more fervently. Casey returned his ardor with all the passion that had been pent up inside of her for so long. Soon Derek's mouth had moved and was pressing little kisses on her chin and neck. It felt incredible. As he made his way further and further down, Casey came to her senses. "Derek," she murmured.

His mouth was on his chest now, just above the cut of her sweater. "Don't…" he said between kisses, "ruin…it."

"Derek," she said louder. He ignored her. "Derek."

Irritated at being interrupted, Derek paused and looked at her. "What?"

"I—" Unable to think of what to say, she reluctantly pushed him away. "You—"

She was aware of Derek's eyes on her, watching her every move. Why was he confusing her so much lately?

When she looked up, his eyes locked with hers. His eyes were questioning, and they held emotions she'd never seen in Derek before.

Without another word, she slipped out from behind him and exited his room.

oooooooooooooooooooooooooooooooooooo

Back in Casey's own room, she began the complicated task of dissecting her feelings.

She loved Sam, she was sure of it. He was sweet and funny, polite, honest…everything she looked for in a boy. He was romantic and took her on the most amazing dates. He comforted her when she was down; he apologized when he made her angry. He laughed at her sad attempts at jokes, and made some pretty good ones of his own. He respected her opinions and feelings, and listened to all her tirades. Casey could come up with a million and one good qualities Sam possessed; he was everything Derek wasn't.

Derek – her arrogant, rude, disgusting, flirty, messy, selfish, stubborn, unhygienic, womanizing pig of a stepbrother. The complete opposite of his best friend, and yet…he made her feel things. Things she didn't want him to make her feel. She wanted Sam to be the one to induce these feelings.

Ever since they'd started the kissing lessons, things had become increasingly different between Derek and Casey. They still fought, sure, but they now had more…personal relationship. Casey had refused to acknowledge it. She wanted things to go back to normal.

But every time they kissed, Casey knew she'd never felt anything like it. At first she'd thought it was normal for a kiss to feel the way it did. So why did she feel nothing with Sam? Sam was perfect for her. Why wasn't kissing him as exciting as she'd expected?

Casey groaned and buried her face in her pillow. So much for this kissing lessons thing solving her problems. It had only made them more confusing.

ooooooooooooooooooooooooooooooo

When Casey made her way downstairs Monday morning, Derek was already there, munching away on his cereal. For a moment, he hadn't noticed her standing there yet, and she watched him as he scooped up large amounts of milk and cereal and thrust them into his mouth, chomping down like an animal, milk streaming out of his mouth. Normally Casey would be disgusted by this scene, but today…something was different. All she could see was the way his orange-brown hair messily framed his face, the thoughtful expression he wore, the toned arms that had so gently held her, the lips that had so sensuously caressed her own…

Suddenly Derek looked up and his eyes locked onto hers. His expression was blank, but somehow Casey couldn't look away.

"Ready for school, Case?" she spun around to find her mother coming up behind her.

"Oh, yeah," Casey replied, emerging from her trance. "Just, uh, trying to think if I'm forgetting anything."

Derek snorted into his cereal, but Casey ignored him.

ooooooooooooooooooooooooooooooooooo

"Hey, Case?" Nora called from upstairs when Casey arrived home from school a couple days later. "Do you mind babysitting for Marti this evening? George and I have to go to Lizzie and Edwin's parent teacher conferences tonight and we thought we'd get some dinner on the way."

Casey groaned. Derek, who had come in behind her, was laughing infuriatingly.

"Can't Derek do it?" Casey called back.

Nora appeared at the top of the stairs. "That's not a bad point." She shifted her gaze to Derek, whose smirk still reigned. "Derek?"

"Sorry, can't." He pretended to look disappointed. "I'm going over to practice hockey plays with some of the guys. Maybe next time though."

Casey gave him a withering look and turned back to her mother. "Mom, that's not fair," she complained. "There are plenty of other things I could be doing if I wasn't babysitting Marti. Can't Derek do it for once?"

"How about you do it together?" George suggested, coming up next to Nora.

"You know," she said, ignoring the protests of Derek and Casey, "that's not a bad idea."

"What?"

"Mom!"

"That's not fair!"

"Shouldn't Derek do it by himself? I always babysit."

"You like babysitting," Derek retorted, stepping forward.

"Maybe I only do it to prove to Marti that she has at least one responsible older sibling." Casey shot back as she took a step forward as well.

"There's no reason you two can't learn to cooperate and get along," George spoke up. "Derek, you can reschedule," he gave Derek a stern look, "and Casey can help out since she is, after all, more responsible." Casey looked put off at having her words thrown back at her.

"Okay," Derek said ten minutes later after George and Nora left with Edwin and Lizzie, "I'll leave Marti to you, since you're the responsible one, and I'll go play hockey with the guys."

"I don't think so, Derek," Casey retorted, catching his arm as he tried to walk away. Their eyes met, and they engaged in a sort of staring contest, each challenging the other.

"Alright," Derek said, answering the unspoken provocation, "you decide what to do then."

"I want to play hide-and-seek!" Marti piped up. Casey and Derek turned; they hadn't been aware of Marti standing just behind them.

"Are you finished with your dinner?" Casey asked her, putting on a smile for her youngest step-sibling.

"I don't like fish sticks. I want to play hide-and-seek. I want Smerek to play too."

So that was how Casey found herself crammed in a secluded area underneath the back porch, cringing at the thought of all the mud and cobwebs she was probably sitting in.

"Ready or not, here I come!" Marti shrieked as she finished counting. It was the fourth round of the game; Casey and Derek had both taken turns being the seeker, Casey having gone twice, and now it was Marti's turn.

Casey sat quietly, listening to the rustle of the wind blowing the leaves and the steady chirp of crickets. She waited to hear Marti's call of "I found you!" as her cheerful face appeared under the deck, or possibly her shrieks as she chased Derek.

What she didn't expect was to hear a deep voice beside her mutter, "Hey."

"Derek," she whispered back, "this spot is already taken. You have to find somewhere else to hide."

He grinned as he settled down next to her amid piles of dirt and dead leaves. "You know I never follow the rules."

Casey didn't know why Derek had insisted on hiding under this porch with her. Neither of them spoke; well, that was to be expected, as this was a game of hide-and-seek, and it's never fun to make it easy for the seeker to find you.

In fact, for someone who had been so insistent on not babysitting, he seemed to be rather enjoying himself.

When she felt Derek's hand slip into hers, it felt warm and comforting. It was as if all her worries disappeared with the simple warmth of his touch. Somehow, just holding Derek's hand caused her to feel more emotion than kissing Sam. Why?

Caught up in the moment, Casey leaned toward Derek and caught his lips with her own. He kissed her back for a moment, and then broke away.

"I can't do this anymore, Casey," he said softly. He pulled his hand out of hers. "We can't keep doing this."

"Why not?" She was unable to see his face, which was hidden in shadow. She wondered what emotion his expression held, whether she should be glad she could not see it.

"Casey…" he trailed off, once again pressing a kiss to her lips. But unlike the other kisses they'd shared, heavy, full of passion, this one was soft and mournful and only spoke of how Derek truly felt, what he wanted.

"Oh," Casey breathed as he pulled away. Without another word, he crawled out from under the deck, once again leaving Casey to her thoughts. In the distance she could hear Marti's joyful cries at having found Derek out of his hiding place, and his forced laughter as he allowed Marti to chase him around the yard.