The room reeked of sweat, panic, and fear with a hint of sage and cinnamon. Derek could pick out a few other scents, but they were too faint and he didn't want to waste time on trying to decipher them. Except for the one he couldn't ignore - sulfur.

"You weren't lying," he stated, taking in the dirty clothes scattered across the floor, the unmade bed and the messy desk.

Stiles flailed from across his room, smacking his hand against the desk and cursing. "Why would I lie?" Derek raised an eyebrow and decided to ignore the young man, focusing instead on the scents around him.

"It was standing here." Derek was talking more to himself, but he felt the human's eyes on him as he moved closer to the desk. "It wasn't here for long, though. The scent of sulfur isn't strong."

"It did only happen earlier today, so it-"

"Doesn't matter," Derek interrupted, glancing around the room again. "Werewolves have heightened senses. Depending on the smell and how strong it is, we can make pretty good estimates of timeframes."

"Dude, that's so cool!"

The werewolf turned his head toward the bedroom door when he got a whiff of bitter distress. He followed it out of the room, down the hall and to an open doorway, ignoring Stiles rambling behind him. He pushed the door open further and the scent of distress got stronger, stinging his nose.

"This is my dad's room. Why...?"

"He put up a fight," he affirmed as he scanned the barren room.

The boy pushed past him, stopping and shifting nervously a few feet away. But when he spoke, his voice was firm and confident, "Of course he would. He's a cop."

Derek nodded, using his senses to try to find anything else that would be out of place. The bed was in a disarray, miscellaneous items on the nightstand knocked over, the closet door set at an awkward angle.

"It happened early in the morning." Derek slowly paced the room, taking in every little detail. "He stumbled around a bit, probably didn't have the light on."

"He had to work a double shift yesterday," Stiles replied. "He usually gets home around one or two in the morning after one of those, sometimes even later."

Derek made a small noise of acknowledgement in the back of his throat when a shiny glimmer caught his eye. He crouched down by the bed to find the source, reaching his hand out across the carpet. His fingers tapped against cold metal and he lifted it up to get a better look.

"That's my dad's badge," Stiles whispered, the fresh smell of salt dancing through the air. The werewolf glanced over at him then stood and placed the badge in the young boy's hand.

"We'll find him." He relaxed his tense muscles slightly in favor of attempting to give the human a soft, genuine look when those amber eyes met his. "Can't have you losing your job now, can we?"

Stiles lips quirked up into a grin. "No, we can't."

Derek took a step back and gave the room one more glance over. "There's not much else here. But I know someone who may be able to help. You got a car?"

Stiles snorted and wandered back to his room, grabbing a set of car keys off his desk. "Do I have a car? Psh!" Derek followed him out of the house and over to a blue, dying monstrosity parked in the driveway.

He stopped in front of it and raised both eyebrows. "This is your car?"

"Don't! Roscoe can hear you!" Stiles glared at him, hand on the driver's door handle, the other one holding his keys and pointing a finger at him.

Derek rolled his eyes and climbed into the passenger seat. He barely paid any attention to the human as his thoughts drifted to the demon, a demon who knew too much about him. He had been honest when he'd told Stiles he didn't know much about demons and he didn't particularly care to know more. But this one... This one he wanted to know as much as possible.

"Hello?" A hand waved in front of his face and he blinked, jerking his head back and grabbing the wrist tightly. "Ow, ow, ow! Fragile human here!" Derek immediately let go and watched the boy rub the appendage, holding it close to his chest. "Did you really have to do that? That freaking hurt, dude!"

"Start the car," Derek said, turning his attention out the passenger window. The boy grumbled, but it was barely heard over the roar of the engine as it came to life. He stayed silent during the drive, only speaking to give Stiles directions.

After a short while, they pulled up to a small building, the parking lot vacant in the early morning light. Derek stepped out of the car and made his way to the front door, barely acknowledging Stiles stumbling and flailing after him. He gripped the door handle and pushed on the door.

Locked.

"Uh, why are we at the vet's office?" Stiles inquired from beside him. Derek ignored him in favor of slamming his shoulder against the door, shoving it open and leaving part of the door frame slightly cracked. "Dude!"

"Derek," a calm, steady voice met his ears as he stepped into the small waiting room. He looked over in the direction the voice had come to see a bald man standing behind the counter, giving him a blank stare. "It's a bit early, don't you think?"

"We need your help." The man's eyebrows raised when Stiles stepped in behind Derek.

"And to what do I owe the pleasure?"

"What do you know about demons?"

The man pursed his lips together. "They're very dark creatures, Derek. I'm not sure you want to know."

Derek opened his mouth to respond, but Stiles beat him to it. "Hey, dude, I'm trying to find my dad and Derek said you might know something. Can you just help us out?" The man gave Stiles a displeased look and the boy fidgeted. "I'm Stiles, by the way."

Derek growled when the man didn't say a word, just looked at them with that unreadable expression. "Deaton. I'm asking nicely."

Deaton let out a heavy breath and moved toward the back room, motioning for them to follow. "There's a wide variety of demons out there. They all have their own powers, tricks, disguises... They're surrounded by black magic, summoned from it. People believe they come from Hell, which some do. But others come from your worst nightmare, the desires of your heart. Because of this, it's nearly impossible to track one down."

"Great, so, you're saying my dad's gone forever," Stiles said as they crowded around a small surgery table. "That's fantastic. Just what I needed in my life."

"Stiles," Derek snapped, arms folded over his chest. "Shut up." The werewolf turned back to the veterinarian, easing his glare ever so slightly. "This idiot summoned one for fun and it kidnapped his dad. Then it sent him my way and told him he had to help me find a mate or it'd kill his father. What kind of demon would that?"

Deaton looked down, his brow pulled down into a thoughtful expression. "Hm. It definitely seems like a trickster to me. It could easily be one from a nightmare or his past."

"No. I would've recognized her."

Deaton snapped his eyes up to the young man in surprise. "You saw it?"

Stiles nodded. "She told me everything I needed to know to do her bidding, I guess. Stood in my room and everything. Looked super real."

"Can you describe what it looked like?"

The human twiddled his fingers as he gazed up at the ceiling, his face set in a concentrated expression. "She was skinny with long blonde hair. Wore a lot of black. She had this weird, creepy grin on her face and her eyes were pitch black, not even a speck of light reflected from them. Had some gunholsters on, but they were empty."

Derek's blood ran ice cold, his eyes locked on Stiles as his heart slammed against his chest.

No. It couldn't be.

"She wasn't see-through or had any dark mist surrounding her?" Stiles shook his head as he looked back at the man across from him. "Then it wasn't just a nightmare. She had been a living person at some point. Probably came straight from Hell." Deaton glanced at him. "Derek, would you like to share something with us?"

Stiles turned sharply to him. "You know something?"

Derek glared icily at the older man. "No. It just sounded familiar."

"Oh." The human reverted his attention back to deaton. "So, what can you deduce from this?"

Deaton shifted slightly, looking between the two. "Like I said, it's a spirit that was cast down to Hell. If you summoned her, she must be tethered to you somehow."

"Is there a way to get rid of her?"

"There are many ways to get rid of demons. However, seeing how she may not be a demon, but rather a spirit... Well, that may be a little harder. I'll look into it and let you know what I find."

"Thanks, doc."

Deaton nodded and showed them the way out, grabbing Derek's attention at the very last second when Stiles was already out by his jeep. "Derek. Be careful with that boy."

Derek's jaw clenched and he stepped outside without another word. Stiles revved the engine once the werewolf was inside, staring out the windshield. "So what now?"

"Now we wait."

"We-Are you kidding me?" Stiles swivelled in his seat, eyes wide. Derek raised an eyebrow at the frantic movement. "You have no clue how to help me find my dad, so your best idea is to go to some creepy animal doctor, ask him if he knows anything and then wait when he basically gives us nothing to start with?! Are you serious?"

Derek's voice was surprisingly calm when he responded, "I told you, I've only heard stories. Deaton isn't just a veterinarian. He knows about the supernatural, more than he lets on. He can get us information." Stiles shook his head, then slammed on the accelerator, speeding toward town. "Where are we going?"

"Somewhere I can do my own research."

"You don't trust me."

"I just met you! Of course I don't trust you!"

"And yet you know so much about me where I know next to nothing about you."

"Touché." Derek rolled his eyes and stared out the passenger window. "What do you want to know about me?"

"Nothing."

"It's only fair, dude."

Derek looked back at the boy, but he was focusing on driving, one hand on the wheel and the other resting on his leg as it jittered slightly. "When did you find out about your magic?"

"Why that question first?" Stiles huffed, reducing his speed the further into town he got. "It happened when I was having a panic attack a few years ago. I ended up hurting myself on accident and it snapped me out of it really quick." He side-glanced over at Derek. "Don't ask."

Derek's lips twitched upward in amusement. "Did you find someone to help train you?"

"Nope. I taught myself. I'm nothing spectacular though. Just know a few things here and there."

"Like teleporting."

Stiles gave him a cheeky grin. "Yeah, that was pretty great. Haven't done that since high school."

"How old are you?"

"Twenty-two." Stiles pulled his jeep into a parking spot and turned the engine off. Derek noticed he hadn't asked him the same question as they walked into the library.

"Did the spirit tell you how old I am?"

Stiles made a bee-line for the computers, tossing over his shoulder, "Nope."

"You don't want to know?" Derek questioned as he stood beside Stiles, watching him settle into the seat and start the computer up."

"Sure I do. But you're asking questions about me, remember?" Derek blinked, but didn't respond. He watched the boy start typing furiously on the keyboard, then attack the mouse as his eyes moved quickly across the screen. He sat there for a few minutes, just enough time for Derek to glance around the empty library. "Found something!"

Derek bent over, resting one hand on the desk beside the keyboard and the other on the back of the chair. He felt Stiles' eyes on him, but he focused on the screen, trying to find whatever the boy had found. "What is it?"

"Oh, right, um. Right here." He moved the mouse and highlighted a small paragraph. "It says how you can summon a spirit to where you are and how to get rid of it. I think it might work."

"Confrontation? Won't that just upset it?"

"It might. I can keep looking if you want, but we're just wasting time that we could be using to find my dad."

Derek hesitated, then sighed. "Fine. Let's try it."

"Okay, sweet! Now we just need to find a good place to summon her."

A heavy feeling settled into Derek's gut, his wolf restless in the back of his mind. Something inside of him screamed that this was a horrible idea, but another part of him wanted Stiles to stop smelling of anxiety.

He was so screwed.