Liar, Liar

Summary: Casey likes Derek. Derek is suspicious. Casey lies. Derek knows better...and isn't going to let her get off that easily.

Author's Note: I do not own Life With Derek

"Run your mouth,
I bet I can catch it."
- Sara Bareilles

Casey had been acting differently lately and Derek was determined to get to the bottom of why. For the past few weeks, she'd been more flustered around him, and her comebacks weren't quite as sharp as they normally were. Something was eating her, and Derek decided it was his mission to find out what. After dinner one night, he grabbed Edwin by the collar of his shirt and dragged him into his bedroom. Slamming the door shut, Derek demanded to know what was going on.

"How would I know?" Edwin protested.

"Because you have like tabs on everyone in this house. You and Lizzie always are the first to know what's going on with everyone."

"Well I don't this time. I swear! She has been moodier lately. But I just figured that was just PMS or something..."

"Do not use that word in my room ever!" Derek fumed, "This room is the only place in this house sacred from that word. So do not say it in here...ever. Understood? And no, it's not that. She's really different lately. Like really different. And not just normal Casey moody and bitter but like there's actually something bothering her."

"What do you care anyways?" Edwin tried to stand up from the bed, but Derek just pushed him back down.

"I don't," his chin jutted out slightly, "It's just...she's not fun anymore to mess with. And her crappy mood is killin' my mood. So I need to fix this. Now."

"Okay, okay. I can see if Lizzie can see if there's anything wrong with her. But dude, you gotta chill. It's just Casey. You know how she can be sometimes."

"Do I," Derek rolled his eyes, "Alright. You're dismissed."

Edwin left, shutting the door behind him. Derek paced around his bedroom, brooding. Casey was the only entertainment he really had in this house when there wasn't a hockey game on or when George and Nora changed the password on the internet's child lock. Messing with her was how he got his kicks. If she was just going to be broody and boring, where was the fun in that?

Mentally, Derek ticked off typical Casey behaviors. It couldn't be a break up. If it was a break up, there'd be crying. And ice cream. And sad music wafting from her room. No, it wasn't a break up. A fight with a boyfriend? But Casey wasn't currently with anyone was she? No, Derek concluded, she couldn't be. If she was, he'd know about it. Not that he really kept tabs...

A fight with Em? Their fights were always usually petty and over within the same hour. If not that, then what?

Who knew how long it'd take for Edwin to talk to Lizzie and then for Lizzie to talk to Casey. Derek knew better by now that if he wanted something done right, he needed to take care of it himself. So he ran a hand through his hair and marched across the hall to Casey's room. Knocking was a foreign word to him, and Derek barged in without doing so.

"Derek!" Casey jumped a little. Yeah, she really was on edge. Normally she was just used to him coming in, and wouldn't act jumpy - just pissed. Derek leaned against the door frame.

"Spacey," he raised an eyebrow, "We need to have a chat."

"Do we?" Casey stood from her computer chair, "And what, may I ask, about?"

"You."

"Me?"

"Yes. You. You've been weird lately and I'm going to find out why."

"You are?" Casey folded her arms over her chest, unamused, "And what makes you think there's anything wrong with me?"

Derek wet his lips, "I know you. So are you going to spill or what?"

"Nothing is wrong with me," Casey tucked a strand of hair behind her ear and averted her eyes to the carpeting, "I've just been tired lately. I think I might be getting a cold...I feel sort of run down...maybe I should take some Vitamin C. With midterms coming up, I can't be getting sick..."

"Case," Derek kicked the door shut, "You think I can't tell when you're lying? You're averting your eyes and you're rambling. Now spill."

Casey rocked back on her heels a bit. The cogs turned inside her head. She needed to come up with something. And fast too! Why did he have to always read her so well. She wasn't that open of a book. Sighing, Casey pointedly raised her eyes to meet his. She kept her voice level as she said, "Fine, you really want to know what's been on my mind?"

"Yes," Derek said, his voice was quiet and genuine. He needed to get Casey to open up.

"Okay. If you must know, it's Emily. She uh...I can't believe I'm telling you this - I promised I wouldn't," Casey rolled her eyes, "but you won't leave me alone unless I do. So I might as well just tell you. She...she has a crush on you."

"What?"

"Yeah...she uh...she likes you. A lot. And just keeping that a secret has had me kind of wound up lately."

Derek nodded slowly. Was she really pulling that one? Had he not just said he could always tell when she was lying? It was a bold move to just flat out lie to his face. There was no way he was just going to let her get away with doing that.

"Well, thanks for telling me then," Derek nodded solemnly, "I appreciate your honesty, Case." He raised an eyebrow, watching her flounder a bit under the word 'honesty.'

"Uh-huh!" Casey turned back to her computer, "Well, I have to finish this History assignment, so..."

"Got it," Derek backed towards the door, "Again, thank you for telling me."

"Uh-huh!"

Derek shut the door behind him as he left her room. Once the door clicked shut, a massive smirk spread across his face. Yes, Casey. Thank you so very much for your honesty.