Title: It's Complicated Because We Make It So

Summary: Why don't you try to sort out your feelings while dealing with your sex-crazed wild child cousin and a pack of bloodthirsty alpha werewolves?

Rating: I suggest you go look at the ratings for my other stories. And then make a guess.

Disclaimer: Trust me, I don't own this show. It would be less cheesy and Sterek would be canon if that were the case.

Author's Note: I have a dear friend. This friend and I disagree on what makes something a good television show. So, we came to an agreement – for every season of her television shows that I watched, she would watch a season of mine. I just traded in two seasons of Teen Wolf for both seasons of Sherlock (since they're so short) and the first season of Downton Abbey. Now, I still don't like Teen Wolf in general, but I have to admit – I thought Stiles and Derek were in a relationship. No, seriously. I did. And with that, ladies and gentlemen, I joined the hoard of fervent Sterek shippers out there.

Cookies, anyone?

"Stiles!"

The youngest member of the Stilinski household (Population: 2) looked up from his book.

"Yeah?"

"Come help me set up the guest room!" His dad called.

A guest? Stiles set down Lycanthropy and You, a joke guide to living with werewolves similar to The Zombie Survival Guide. Some of it was the usual rubbish but other bits were surprisingly accurate, leading Stiles to re-read it and write down notes. He'd ask Derek about it the next time he saw the guy. THE big, hunky brooder hadn't been around the past few days. Not that Stiles cared. Or missed him. Not at all.

He crossed the hall to the guest room to find his dad putting clean sheets on the unused bed. He looked up as he heard Stiles enter.

"Great." Sheriff Stilinski turned and snatched up a spray bottled of window cleaner, chucking it at his son. "I want those windows spotless. I already dusted so all that you have to do is vacuum."

"Seriously?" Stiles was more than a little annoyed at this. Cleaning was not his thing. Annoying the hell out of certain Alpha werewolves? Sure, anytime, anywhere. Cleaning? Not so much.

"Who's visiting?" He asked.

"Cassie." His dad replied.

Oh, boy.

Oh boy oh boy oh boy.

Cousin Cassie.

"Really? How long is she staying?"

"About a week. She's on a cross-country road trip and decided to stop by."

Oh, man. They were in for it now.

There were several reasons why having Cassandra "Cassie" Stilinski in Beacon Hills, CA, was a bad idea.

First and foremost was Cassie's sexuality. Cassie had sex. All the time. With anyone. In fact, her only rule was that they had to be single. Except for threesomes; she'd had her first threesome when she was sixteen. Boys, girls, whatever – Cassie was on it. Sometimes, literally.

Not only was it extremely irksome for Stiles, Mr. Never Been Kissed Never Mind Grand-Slammed, to hear every dirty detail of his nineteen-year-old cousin's exploits, but if you were to throw her in with the crazy hormone pool that was a bunch of teenage werewolves, well… even Stiles didn't want to set that bomb off it he could help it. He could pictures his cousin easily working her way through the pack, except for Scott and Allison, who were too tight-knit for that. And Derek. Not even Cassie-nova could melt that block of icy wolf badassery. At least… He hoped not.

Reason number two as to why having Cassie around sent up red flags and huge sirens wailing and signs flashing "warning" was that Cassie was curious. Like, Curious George levels of insatiable inquisitiveness. Everyone thought Stiles was bad, but they had no idea. Cassie would figure out what was going on with Stiles and the pack in two seconds, if that.

Numero tres was that Cassie was the single most determined and mule-headed person that Stiles knew. Part of him wanted to watch her go head-to-head with Derek over something. That'd be fun. Heck, Stiles would even bring popcorn to watch that battle.

Yes, Stiles had good reason to be worried about Cassie visiting.

And, as often happened to him since, well, ever, his worst fears were confirmed and everything went downhill from the beginning.

"So this is your room, huh? Nice."

"Uh-huh." Stiles replied, flinging Cassie's surprisingly small and rather light backpack onto her bed in the guest room. His dad was working, so he was the one welcoming Cassie and getting her settled.

"Nice pile of laundry you got – holy fuck!" Cassie screamed mid-sentence. This was followed by a very loud thump.

Stiles barreled into his room to find Cassie had her heel planted firmly on someone's back, with their arms held behind them in her hands and a can of mace pointed at their face. When Stiles came around to the side, he found that the person was a slightly confused and very pissed off Derek Hale. The older male's eyes turned and focused laser like on Stiles.

"Stiles," He said slowly, "Who is this?"

"This is my cousin, Cassie."

Derek gave him a look.

"Dude, she really is my cousin. I swear." Stiles put his hands up.

Cassie lowered the mace, released Derek's hands and stepped away, nothing the rather intense look that Derek was giving her cousin. "Um, Stiles, who is this?" She asked. "And why did he creep through your window?"

Stiles groaned. "Derek, c'mon, man. The window is not a door. You can knock."

Derek just did that staring thing of his. Stiles sighed again and turned to his cousin.

"This is my, uh…" His what? Sometimes ally? Pain in the butt? Creepy semi-stalker? Random smokin' hot dude? Local alpha werewolf? "This is Derek."

Cassie's eyes flicked back and forth between the two of them. "Hi." She finally said slowly.

"How'd you learn to do that?" Stiles asked. Seriously, anyone who could get the drop on Derek Hale had his respect for life.

"Between the pickpockets in Europe, the animals in Africa, the political unrest in South America and the rapists in the good ol' U.S. of A., I decided I needed to learn a few things." Cassie said, still looking from one boy to the other like they were a puzzle she couldn't quite figure out.

Cassie had, indeed, gone to all of those continents. She'd decided that she wanted to spend her life traveling and had promptly gotten her GED and an Associate's Degree in Liberal Arts by the time she was sixteen, getting emancipated from her mother and had set off to globe-trot. She'd backpacked all over Europe and Asia, taken every damn safari in Africa and begged, borrowed, and stolen her way through South America before ending up back in her country of origin.

Stiles didn't realize that he was explaining all of this out loud to Derek until he realized that Derek was giving him his classic shut up before I make you face and Cassie was staring at him like he'd sprouted another head.

"Oh, I'm rambling, aren't I?" Stiles asked. "Right, yeah, shutting up now."

His filter control was about fifty percent normally, but around Derek it tended to go down to fifteen percent.

"So… where are you going next, Cassie?" Stiles asked.

Cassie frowned. "I'm going to Canada and Alaska in the fall, after I finish with the U.S. Then I'm going to island hop from Hawaii all over Oceania before I end up in Australia in time for spring."

"Nice." Stiles nodded fervently.

Derek still said nothing.

Cassie gestured. "Look, should I leave you two alone or something? Let you boys get to it?"

Upon getting no answer, she opted for a swift exit. Stiles could hear her enter the guest room, heard a zipper being pulled down and assumed that she was digging into her backpack. He cleared his throat.

"So what's up? Finally gracing me with your presence after however many days of–"

"There's an alpha pack in Beacon Hills." Derek cut in.

"Wait – what? What's an alpha pack? How'd you learn about them? Why are you coming to me? What–"

Derek once again cut him off, this time by striding forwards and covering Stiles' mouth with his hand. Stiles tried very hard not to focus on the heat radiating off of the older man's body, or how his hand felt against his skin and lips. Now that he was focused solely on Derek, he was able to take in the werewolf's condition. Derek was extremely tense – and not just normal made-of-stone Derek Hale tense – this was a whole new level of suppressed emotion.

"This is serious." Derek intoned. Well, that was as close to a please as Stiles was ever going to get, so he nodded and Derek removed his hand from Stiles' mouth. Once he'd done that, Derek began to pace.

"An alpha pack is very rare – it only happens when enough werewolf packs have been decimated that only a group of alphas are left. With no packs to lead, the alphas opt to band together. It's a lot less stressful than creating a whole bunch of betas to train. Not to mention you inevitably end up with an omega, and that's added tension that you don't need…" Derek cleared his throat. "The point is that alpha packs are deadly. They don't want to deal with other packs. They don't want betas. They find a particularly large area, one with a huge hunting ground, and they stake it as their territory. It's usually about twice or three times the size of the average territory. Any other packs in the area, they kill. No negotiations."

"Seriously, that sucks." Stiles said. "But that's also stupid. I mean, they're all alphas, right? So they all want to be top dog – no pun intended. But they can't, because there's, like, ten of them, so wouldn't they end up fighting each other or something?"

Derek stared at him like he was surprised that the question was actually pretty intelligent. "Good point." He finally grunted; high praise in Derek terms. "Alpha packs can be anywhere from five to fifteen alphas strong. They work as equals, with decisions being made by voting rather than the usual chain-of-command style. But you're right – they're alphas. They can't stand not being the sole leader forever. After a while, squabbling begins and they begin to create betas to help them gain control of the pack. Several fights later, they split up, each alpha taking their betas and going their separate ways."

Stiles nodded. "Then we're back to small packs with one or two alphas, a few betas, maybe an omega, and all with their own separate territories. Hurray, balance has been restored to the universe."

Derek sighed. "Pretty much."

"So…" Stiles frowned. "You're saying that one of these kill-all-other-packs alpha groups has strolled into town?"

Derek gave one of his best brooding nods. "Yes. Which means that we're all in danger."

"We? Oh, no, buddy. I'm no werewolf, I'm fine." Stiles reminded him, putting his hands up. "And actually, both you and Jackson are safe. You're alphas, right? You can just join up."

Derek snorted. "Some alpha I am. And Jackson was turned a couple of weeks ago. They'd see us as weak; we'd never be accepted into the pack. Besides," His voice lowered into a growl, "I can't abandon the other pups. Erica and Boyd are in bad enough shape as it is, and Isaac still jumps at his own shadow. Scott's still refusing to be pack but you can bet Peter won't do a fucking thing to protect him, so it's up to me to keep the idiot safe."

Stiles sighed. "Let me guess – you want my help in keeping everyone safe, because I'm the only one with half of a brain who isn't addled by wolfy hormones, am I right?"

Derek gave him one of those looks where it was like he was straining very, very hard not to roll his eyes. "I suppose that you could put it that way. But I don't want you getting too deep into this; you're in more danger than any of us. You're human. One punch and you're out of the game."

"Hey! I'll have you know that I am much tougher than that." Stiles said, a bit miffed. "I've survived you slamming me into the wall on several occasions, and getting my forehead slammed into a steering wheel – thanks for that, by the way. I think that I could handle any little spat you wanted to get into with these alpha jerks–"

Derek really needed to find a new way to get his anger out, because Stiles was getting a little tired of feeling his back connect with the wall of his bedroom. He was going to have to see a chiropractor at this rate. Derek's face wasn't even an inch from his, those eyes dangerously close to turning a not-so-natural color.

"You will stay out of danger this time." Derek growled. This wasn't just a low man-voice growl – this was a full-on wolf growl, feral and wild and definitely not human. "Understand?"

Stiles nodded. "Uh-huh. You got it."

"Good."

Stiles frowned. "Um… how'd you find out about this pack, anyway?"

"Erica and Boyd. They barely got away – turned tail and came back to me."

"They apologized for leaving, right?"

Derek cocked his head. Stiles rolled his eyes. Hey, he could roll his eyes and still be manly, okay?

"You're not the best alpha, sure, but you really try. You care about your pack. You want to make a family. You did the best you could for them and all that they did was insult you and run off. I think a little groveling is in order now that they're hiding behind your skirts. Uh, metaphorically speaking."

Derek stared at him, but this time Stiles was surprised to realize that he couldn't read this stare. That led to him realizing that he was able to decipher the emotion or meaning behind Derek's stares, which meant that he could understand the guy better than he'd previously realized, and that just downright startled him. Luckily, Derek interrupted him before his thoughts got out of hand and started chasing each other like horny bunny rabbits.

"Thanks." He grunted.

"Anytime." Stiles nodded. A thought occurred to him. "Hey – what creates an alpha pack? I mean, what destroys all the packs so that only the strongest, wiliest alphas are left to band together?"

Derek didn't appear to have thought of that. "Usually a hunter." He said at last. "A hunter, or group of hunters, that's sweeping through."

"That would have to be one pretty destructive hunter to create an alpha pack that's got – how many members?"

"Ten."

"Right. That's at least ten packs, plus maybe more where the alphas didn't make it and the entire pack got wiped out. Shouldn't we be worried that whoever was responsible for creating this will be coming here to finish the job? I mean, ten alpha werewolves… not exactly subtle, right?"

Derek seemed to actually give this some serious thought. Before he could answer, though, Cassie reentered the room.

"Hey, Stiles, I was just – oh." She paused.

Stiles realized that Derek was still pinning him to the wall, their bodies pressed together and their faces mere breaths apart. Cassie got a sly look in her eyes.

"Sorry; didn't mean to interrupt. Stiles, I'm taking over your shower. It's been a week since I last saw hot water." She waved a hand. "By all means, go back to what you were doing."

She winked and left the room. Stiles groaned and thumped the back of his head against the wall. This was great, just great. Not only did they have a deadly alpha pack and a possible deadly hunter out there to deal with, but his sexpot cousin now thought he was in a gay relationship with Derek Hale.

Seriously, his life kind of sucked.

Whatever Derek thought of the situation, he didn't say. He just let go of Stiles and took a step back, giving Stiles the room to breathe without having their chests crush together. "I need to check on the pups." He said. "I healed Erica and Boyd but they're still shaken up, and Isaac's panicking. I'll be surprised if he hasn't text Scott yet."

"And if Scott knows, Allison knows, and if Allison knows, Lydia knows, which means Jackson knows." Stiles recited. "Ugh."

"Just get your skinny butt over to my house as soon as possible." Derek ordered. "And if you can ditch Chrissie, all the better."

"It's Cassie, and no way. It's like trying to get rid of a leech or something. She's crazy stubborn." Stiles said. "And my butt is not skinny."

Derek ignored him, strolling over to the window. "Five o'clock – be there."

"You're not my alpha, you know!" Stiles yelled after him. "Arrogant, cocky, son of a stinking…" He mumbled.

"Sooo…" Cassie leaned against the doorframe, her hair wet and skin gleaming from the shower. "Playing for the other team, eh?"

Stiles turned and glared at her. "It's none of your business what team I'm playing for, but since you asked it's lacrosse."

Cassie shook her head. "Don't deflect, it's not a good look on you." She gave him an eager grin. "So what's up with Mr. Sneaky Pants? Does your dad know? Is that why he came in through the window?"

"We're not dating, Cassie, I swear." Stiles groaned.

"I won't tell." Cassie assured him. "How long has it been? How did you two meet? How far have you gone? You didn't do it while I was in the shower, did you? I was pretty quick and I don't smell anything so I'm guessing no…"

Stiles opened his mouth to protest again, but then he closed it. This just might be perfect. If Cassie thought that he and Derek were dating, she would focus on that and not on the other weird goings-on he and his friends got up to. She'd attribute any weird behavior to his desire to keep his supposed gay relationship a secret. That meant she wouldn't realize the real secret, because she'd be focusing on the fake secret.

Clearly, there was a God, and He was being rather nice to Stiles Stilinski today. Did this mean he'd have to go to church more often?

"Five o'clock, right? Is that when you and your friends are all hanging out?" Cassie asked. "I can come too, right?"

"Sure." Stiles nodded. "Of course."

If he'd known in advance how the evening would go, he wouldn't have been so optimistic about it.

I have always wanted to write a slutty, wild-child character. They are just so much fun to play with! They say whatever they want, and whatever everyone else is thinking but don't dare speak aloud. Besides, I figured that between Derek's stubbornness and Stiles' ADD they'd need a strong push to get them to admit anything.