Title: The Soundtrack of My Summer

Spoilers from: How I Met Your Step-bro and what I've heard about the status of Derek and Casey at the end of season 4. Plus, if you haven't seen season 4 yet, there's a lot of that in here too.

Summary: It's the summer before Derek and Casey are about to go off to college, so the family decides to spend it in Mexico City. While there, Casey and Derek end up sharing a room, Casey gets a stalker, and Derek figures out just who Casey sees in her dreams.

A/N: The story switches POV's sometimes, so don't let yourself get too confused. And oh yeah... The chapter titles, and the title for the whole fanfic, are based on songs by Boys Like Girls, one of my favorite bands. If you haven't heard of them, you really need to check them out. They're incredible!

Disclaimer: I do not own Life with Derek or Boys Like Girls, but I sure as hell wish I did!

Chapter 1- The Great Escape

(Casey's POV)

Graduation was one of the sappiest moments of my life. I literally spent three hours after the ceremony crying my eyes out with Emily and promising her that we would always keep in touch- even when we're too old to visit, too tired to call, and way too gray to ever look as good as we do now.

Of course, none of that mattered to Derek, my dearest step-brother who I truly believe is the spawn of Satan, brought onto this earth just to cause my demise. He's spent the last few days laughing at my pitiful tears. I couldn't believe he didn't get the least bit choked up at graduation! Even Sam cried! But no! Hugs, tears, and feel-good family moments are way too good for types like Derek.

So when Mom and George announced yesterday morning that the entire family was finally taking that trip to Mexico that we couldn't afford last winter, I almost thought that Derek would've preferred staying home. After all, one last summer of family bonding before we're shipped off to college doesn't mean anything to him.

But to my surprise, Derek was thrilled about going! Probably because he knew there'd be plenty of single girls in Mexico for him to get his hands on. It wouldn't matter to him one bit that he already had a girlfriend- Emily, my best friend.

Which brings me to what I'm doing now. Packing. After George announced that we were spending not just a week but the entire summer in Mexico, I couldn't think of anything that I wouldn't need for the trip!

Fortunately for me, Derek solved that problem. Not!

"So, Ready-Mc-Books-A-Lot, did you think about leaving your library at home for the summer?"

"No, Derek," I scoffed. "I have to bring my favorite novels!"

"Come on! It's summer in Mexico! Are you telling me that you're going to be spending the entire time reading?"

"Not the entire time. I'll take a break for dinner, and going to the bathroom."

Derek rolled his eyes and dumped the contents of my entire suitcase, consisting of thirty books and a few pads of paper so I could take notes, onto the floor.

"Derek!"

"What? I did you a favor! At least now you can find a better way to spend your summer than reading your girly chick novels for the thousandth time."

"And I'm guessing you have a suggestion as to how I should be spending my time, My All-Knowing Step-brother?"

"How about having fun? I hear Mexico has some pretty fantastic beaches. Full of hot blondes and babes in bikinis. Man, this summer is gonna be sweet!"

"No babes in bikinis for you, Derek. You already have a girlfriend, remember?"

"Who, Emily?"

"Yes, my best friend, Emily! Don't tell me you broke her heart already!"

"Nobody's heart was broken," Derek sighed, removing the books I had just replaced into my suitcase. "We both knew it was coming. A summer apart, and then off to separate colleges? No relationship could survive that, Case."

"You mean no relationship of yours, Der. Truman and I are fully committed to a long-distance relationship."

"You mean Truman, the guy who hit on my ex-girlfriend Kendra, my girlfriend at the time Sally, my last girlfriend Emily, and you just after he first moved here? The guy who ranked girls on a scale by their looks? Yeah, there's no way a guy like that is committing to anything close to a long-distance relationship."

"I'll have you know that I just got off the phone with Truman," I countered, placing the books yet again into my already stuffed suitcase. What does he know about Truman and I? Nothing, I tell you. Nothing!

"And what did the cheating scumbag have to say?"

"I think somebody's jealous," I teased in a sing-song voice. "He said that I was important enough to him that he would wait for me until I came home, and then we would talk on the phone everyday once I was off at college."

"For one, jealous of what? And two, Truman is a lying sack of dirt, and you know it! He just reassured you so you wouldn't call him every second to check up on him! That's what I'd do."

"Don't even go there," I shuddered, imagining Derek as my boyfriend instead of Truman. Yuck! Like a person like me would ever be interested in someone like Derek! "And I think you're jealous of the fact that I'm in a happy relationship while you're still hopping from one girl to another like a tree frog during mating season!"

"Okay, I am definitely not jealous of you and Truman! And what about a frog?"

"Oh never mind," I sighed. Derek's brain took about ten seconds longer than the average person to comprehend something. Which I guess wasn't bad, considering one of his best friends was Ralph, and God only knows how that boy can dress himself in the morning!

"Seriously, Case. This summer is supposed to be a cherished time for some family bonding. Don't you want to make some happy memories with your dear step-brother?"

"Like you're going to Mexico because you want family bonding time!" I laughed. "All you care about is girls, hockey, and more girls."

"And food! Don't forget food."

"You're a pig."

"And you're a neat freak."

"Jerk!"

"Princess!"

"Man-whore!"

"Book-whore!"

"Casey! Derek! Time to leave for the airport!"

"Coming, Nora! See you down there, Space Case."

And with one last dumping of my suitcase, my charming step-brother raced out the room and out of sight.

If I wasn't dreading this family vacation before, I definitely am now.