A/N: Okay so I got the idea to write this after I watched the movie Knocked Up (hence the title) for about the 10th time. Although I found it to be kind of obscene at times, it was also really really funny. I thought it was cute how even though the two people were total opposites(one a not-so-smart total slacker without a care in the world and the other an intelligent, career driven, woman) and they were kind of forced together by the baby, in the end they managed to find love and make it work for the child's sake. Then I decided to apply that plot to Life With Derek and make a Dasey out of it! If you haven't seen the movie you probably have no idea what i'm talking about, but oh well! Enjoy=] This chapter is short because it's more of an introduction.

I do not own Life With Derek or the title Knocked Up.

"Derek, shut up!" Casey growled as she stormed into the house, making sure to slam the door in his face.

"Oh c'mon Case, it's funny and you know it. But please, answer me this one question." Casey paused, halfway up the stairs and turned to glare at him. "Were you purposely aiming for the principal's shoes or did he just happen to be in the line of fire?" Casey let out a screech and continued storming her way up the stairs, infuriated by his amusement at her expense. She could still hear him laughing and cringed as she heard him start to tell the excruciating details of what happened at school to the rest of the family.

"Okay so me and Sam are walking down the halls, headed to class of course, when we see none other than our very own Casey McDonald. She's looking a little greener than usual. She's talking to Max. He's gazing deeply into her eyes, when all of a sudden..!" he paused and started cracking up. "Casey turns her head and pukes all over the principal's shoes!"

"Aha nice! Was it gross?" asked Edwin, joining Derek's laughter.

"Yeah it was great!" Derek could not stop smiling.

"That's not funny..that's just awful. Poor Casey." Lizzie said immediately feeling bad for her sister.

"Lizzie's right. And I really wish you wouldn't tease Casey about things like this, Derek you know how sensitive she is." Nora chimed in.

Derek just rolled his eyes. Casey was too sensitive. Besides, it was her fault for humiliating herself in the first place. If she wasn't such a spaz maybe she wouldn't get herself into these situations. As far as he was concerned it was all on her account.

Casey seriously hated Derek right now. As if it wasn't bad enough that she embarrassed herself in front of the whole school, now Derek had to make it worse by making her relive it over and over again. Casey had been so mortified by what happened that she had to spend a whole hour in the nurses office crying before she could finally muster up enough courage to go back out and face her classmates. It was literally the worst thing since the Klutzilla incident. She wished she could just run downstairs and tell him the truth, just to shut him up. Casey fantasized about the look on his face when he found out that the reason she had thrown up in the first place was all his fault. He had done this to her and she shouldn't have to be the only one suffering. She wanted to throw it all in his face right then and there, but knew she couldn't because her family had been present. Also because she had to be absolutely positive first..which was why she called Emily.

"Casey is everything all right? You sounded terrible on the phone." Emily said, walking into her bedroom with a look of pure concern on her face.

"No, I'm not all right Em. I need to tell you something, but you CANNOT tell a soul."

"Casey you know I won't, now spill. What is it?"

"I think I might be pregnant." Emily's eyes went wide.

"What?! No, no, no, Casey that's not possible. You have to have sex to get pregnant." Casey collapsed onto her bed and threw her face into a pillow.

"So you're saying you actually did it? Who's the father? Is it Max?" Casey shook her head no. "Okay, then Sam?" She shook her head again. "Casey who?!"

Just then Derek poked his head in the door and said, "Hey Emily, you better not stand too close to upchuck over here, she could blow any second." He turned on his heel and laughed his way back downstairs. Emily turned around to give Casey an apologetic look when she saw her face had turned pale white. "It's not....Derek is it?" Emily whispered, disbelieving her own words. Casey nodded and threw her face back onto the pillow. "What am I gonna do?" she muffled out.

"Well does he know yet?"

"Obviously not, or else he certainly wouldn't be laughing right now."

"How on earth did this happen?"

"It's really a long, embarrassing story."

"Yeah, well I got nothing but time so spill."

"Okay fine." Casey then went on to tell Emily what she could remember about the night Derek and Casey had promised each other that they would forget.