Title: Why do you have Derek's Loft Keys?

Summary: "Uh... They just showed up?"

Notes: I saw a prompt on tumblr by chance and... this is the result. This and other works also available over on AO3.

"Stiles?" Lydia prompted while Stiles was writing up a section of their assignment before he forgot it. "Why do you have Derek's loft keys?"

"Huh?" he replied, distracted as he finished an equation.

"Derek's keys..." she shook them for emphasis, breaking Stiles out of his focus. "Why do you have them?"

"Uh..." he started at the keys being shaken in front of his face. "They just showed up?" he frowned, confused. "I don't know, maybe he wanted me to keep an eye on the place and is too socially inept to ask like a normal person? Why is this important?" he asked, staring at her impatiently. She just regarded him for a few more silent, thoughtful moment before shrugging and dropping the keys onto the bed spread they were sitting on. He watched her go back to concentrating on her textbook and let his gaze slip to the keys, confusion starting to eat at him.

When he'd taken Lydia home later, he didn't realise he wasn't actually heading back home himself until he stopped outside of the loft complex where Derek lived - or used to live - or was living but wasn't actually there right now...

He was fingering the keys and staring up at the building for ten minutes before he eventually got out of his jeep. Then as he slid open the door, he froze, staring.

It had always been barron, what with Derek not being one for interior design much, but it was empty. A fine layer of dust covered the surfaces, he could see the watermark at the bottom of the mark from where Isaac had had his stupid fucked up plan in place to electrocute Kali a couple of weeks before.

Stiles closed his eyes at the memory - Boyd. Dead.

Unconsciously, his eyes fell on the spot where it happened - where the twins had held Derek's hands out, had forced him to kill Boyd - and he stepped back, closing the door and locking it firmly.

He didn't return for at least a week, though that time he only managed to step inside, close the door and sit on the floor with his back against the door, staring. The third time he went he ventured further in, avoiding key areas. He wasn't there long, but he got the lay of the land.

Over the next month he was there more often, tidying up, dusting, keeping things in order until slowly, bit by bit, he started adding his own belongings in. To start with it was his homework - he left it that by accident one evening. He never put anything more than a kettle, coffee, sugar and milk in the kitchenette. All food he ate there he took out with him again, but he was either in the kitchen or on the sofa and by proximity, the coffee table.

He tried to make sure he didn't take up too much of Derek's space, knowing he probably wouldn't appreciate the small amount he had taken up but whatever. He'd left Stiles his keys, it was an open invitation in Stiles' eyes.

The first time he accidentally fell asleep on the sofa, he woke up with a start, eyes darting around, making sure he was still alone before quickly packing up his stuff and getting out of there.

After that, staying over became semi-regular... two or three times a week. So when Ethan walked into the loft with Danny and Aiden, looking for a venue for a party after Kira had drained the town's electricity, Stiles' eyes narrowed. He'd been doing his homework while simultaneously doing a little bit of research on what the hell Kira was. Scott hadn't said a word to him, which went against the bro-code in Stiles opinion, but Stiles was no idiot. He could read between the lines and deduce.

His dad was a cop you know.

"Stilinski," Aiden said aggressively and Stiles raised an eyebrow.

"Omega1," Stiles' lips twitched. "Omega2, Danny," he nodded his head in greeting.

"Stiles?" Danny frowned, confused. "I thought this place was empty? You guys said it was empty..." he stared at the twins.

"It is," Ethan glared at Stiles.

"The key in my pocket says otherwise," he said helpfully.

"Where's Derek?" Aiden demanded.

"Out of town. You know... after the little incident with Boyd a few weeks back?" Ethan flinched but Aiden just continued to glare.

"Wait, Vernon Boyd?" Danny frowned.

"Oh yeah, didn't your boyfriend tell you?"

"Stilinski!" Ethan snarled and Stiles watched as Danny took a step back.

"Your growl needs work, Derek does it better."

"Whatever's going on, I don't give a crap. All I want is a venue. This whole freaking town has gone to shit lately and we need to unwind." Stiles stared at Danny for a long, considering moment before sighing.

"Abandoned rail yard off 5th. Industrial sector."

"What's wrong with this place?" Aiden growled. "Looks plenty empty to me."

"Don't be a dick all your life, have a day off," Ethan slapped his brother upside the head. "Come on, we can check out the place off 5th." As they were making their exit, Stiles waited until Danny was far enough away before murmuring quietly - loud enough for Ethan to catch.

"Hurt him and it'll be the last thing you ever do," he saw Ethan snap his head around to glare at Stiles but Stiles met it head on, uncaring, unyielding. He waited until the door was shut before relaxing.

Going to the rave hadn't been on his list of things to-do, it wasn't even that good. The girl who he made out with was fun, the realisation that he was blind, not quite as fun, and the realisation that he may possibly have something to do with sending a murderer after his best friend's new love interest? Less fun. But going wasn't high on his list and after his bout of realisations, he made his way back to his jeep and then back to Derek's loft.

Walking up the steps and turning the corner that showed the door for the first time, he didn't even pause when he saw Derek stood there, arms folded over his chest, a bag of honest to God candy in his hand, waiting. Probably for Stiles.

"Thanks," Derek said quietly as Stiles unlocked the padlock on the door and yanked it open before stepping inside ahead of Derek.

"Your nose probably won't thank me later," he commented, not looking back as he walked to the sofa and collapsed.

"I'll deal," Derek said, closing the door behind him.

"So.. how was your night?" eyes closed, head tipped back, he felt the sofa dip beside him, telling him Derek had sat down.

"Scared a few trick or treaters, got my ass handed to me by demons made out of smoke. Yours?"

"Met a girl, realised I like boys too, threatened the twins and discovered I might be losing my might to the point where I'm attempting to kill my friends."

"Sucks." Stiles snorted and heard Derek huff out an amused breath too.

"Not the welcome home you imagined?"

"Could've been worse..." Stiles didn't open his eyes but he smiled.

The next morning he woke up with a crick in his neck and a werewolf on his shoulder. He couldn't bring himself to mind too much.