Derek always wears a key around his neck. It's on a thin chain, like dog tags. No one really knows why it's there or why he wears it or what it unlocks…if it even unlocks anything. But it's always there, as trademarked as his leather jacket.

No one ever noticed it before…well, except for Stiles. He, of course, was the first to notice it, months before the Nogitsune and the sacrifices and the dying and coming back to life.

"What does it unlock?" Stiles asked one afternoon as he helped Derek clean up after a pack meeting.

"Huh?" Derek asked, confused.

"The key around your neck. What does it unlock?"

"Don't worry about it." Derek huffed. "Grab those cups and toss them in the trash."

"Jeez, I should start calling you Bossywolf." Stiles said, snickering at his own joke.

After things got bad, after the Nogitsune possessed the pack human, things changed. Derek was more involved in the pack's lives. He became more welcomed rather than feared. He helped, he healed, he taught, and he learned. There was sort of this mutual equality and respect between Derek and Scott that traveled throughout the rest of the pack. It was nice, good. Until it wasn't.

Stiles' first nightmare was to be expected. No one goes through what he went through and comes out without scars. Stiles was hurt, broken, and while he did a good job of hiding it from the rest of the pack, Derek saw him. Really saw him. Scars and all. So after his first few nightmares, Derek stayed within earshot of the Stilinski home, and would be at Stiles' window in minutes if he heard his heartbeat stutter or his breath hitch…telltale signs of an oncoming night terror that usually brought a brutal panic attack with it.

For two months, Derek would come in through the window almost every night to check on the boy, who was everything to him. His ears wear acclimated to picking up the slightest noise or a pattern of Stiles' heartbeat that indicated suffering or pain, and he would be at the boy's side in minutes, holding him and calming him down and assuring him that he was alright, and that no, despite what the voice in Stiles' mind was telling him, he didn't hurt anyone tonight.

It was raining that night. The night when things went from bad to worse. The night when even the sheriff couldn't calm Stiles down after he woke up screaming and sobbing and shaking and couldn't breathe and—

Derek.

That's who would help. That's who would make it better. Stiles was crying and terrified and he knew... he knew he needed Derek.

And of course Derek was already on his way. Of course Derek was sprinting through the woods in the rain at 2:47am. Of course he heard his boy cry out for him and of course he knew exactly what he needed to do when he got to him.

The sheriff opened the front door for Derek at 2:51am, something he had never actually done before, though Derek had been inside more times than he could count.

"Stiles is—"

"I know." Derek put a hand on John's shoulder and squeezed. "He'll be okay. He's just scared."

John gave Derek a tired smile and gestured for him to go upstairs.

Derek took the stairs two at a time and nearly ran to Stiles' bedroom. He opened the door slowly, as to not scare the boy even further.

"Stiles it's me." he said softly as he stepped inside. He blindly walked to where he knew Stiles would be, guided only by his memory of the layout of the room, to the space in between Stiles' desk and the wall. Even in the dark, Derek could make out Stiles' figure, balled up on the floor hugging his knees. He could hear the boy's heartbeat, frantic and sporadic and so fast. It was so fast. He could sense the shakiness, the fear, the panic.

"Der—" Stiles tried, but he was interrupted by his inability to breathe and so he wheezed and gasped and squeezed his hands into balls and tried to keep his grip on reality but he couldn't so he kept his eyes on Derek because he knew that this was real. Derek was real and he would help. Derek could help him come back he just needed—

Derek knew what he needed. He sat down with the boy and put a warm hand on Stiles' back. Derek could feel the cold sweat through the thin material of his shirt. He rubbed big, lazy circles and suddenly it was a little easier for Stiles to breathe. Stiles leaned into Derek's touch, trying so hard to get as close as he could until he was nearly sitting in Derek's lap but he needed this and he needed Derek so he didn't care and he tried to get closer still. He wanted so badly to be held and to be protected and to be safe and he knew Derek would give him all of that but he couldn't find the breath or the words to ask so he just curled into Derek and hoped his wolf would catch on… and of course his wolf did.

"Hey, hey…Stiles, hey," Derek cupped Stiles' head in his hand and kept their eyes locked. "You know how this goes. You know I'm here. You know I got you. Okay? I got you. Say it."

"You got me." Stiles whispered, his voice shaky and full of tears.

"I got you." Derek repeated back to him. "I want to breathe while I count to four, okay?"

Stiles nodded. He inhaled until Derek reached four, and exhaled until Derek counted back to zero. Again. Again. Again. And then he could feel his fingertips and his toes and he knew Derek had him.

Thunder crashed outside his window and Stiles didn't mean to flinch but he did. He closed his eyes as Derek ran his thumb over the boy's temple and pressed a kiss to his forehead. Stiles tried to make his hands stop shaking. He balled them into fists and hoped Derek wouldn't notice but of course Derek noticed and so he held Stiles a little tighter and ran his fingers through Stiles' hair because he knew it was something his mom used to do and maybe he hummed a song too, and maybe it was the lullaby Derek's mother used to sing to him, but no one would know except for the wolf and his boy.

After Derek had hummed the song a couple times through, and Stiles had buried himself in the warmth that was Derek Hale, he did the one thing he knew Stiles never liked.

"Which one was it?" he asked. Stiles knew this was coming. Derek always asks which of their realities plays back in Stiles' mind in the form of a nightmare.

Stiles' heartbeat picked up a bit and he shifted in Derek's lap. He sighed before he started talking.

"You." He said.

"Me?"

"You. I hurt you. And them. I hurt them too."

"Who's them?"

Stiles couldn't bring himself to answer.

"Stiles." Derek pressed.

"Your—" Stiles looked at the floor. "Your family." He looked up at Derek, waiting in almost physical pain for the wolf to get up and leave him there on the floor. And of course the wolf didn't.

Instead, Derek held the boy as he cried. Stiles cried because he couldn't escape the grip of reality, even when he was asleep and it twisted itself into a knot in Stiles' head. He cried because even the thought of hurting Derek or anyone for that matter made him physically sick. He cried because he didn't think he deserved to be the one who lived…not after everything he—it did. He cried because he secretly wanted Derek to just make it all go away and because he knew Derek couldn't do that. He cried because despite everything, despite how fucked up he was, Derek stayed. He stayed. He stayed and he held Stiles and Stiles held onto Derek because Derek was the last shred of sanity he afforded himself and that—

He couldn't lose that. He couldn't lose Derek. Not him too.

It was then that Stiles realized that the warm hands had left his freezing skin, and he felt Derek shifting underneath him.

No. No please don't—

Stiles let out a noise that sounded pathetic even to himself. "Please no—" he whimpered.

"Shh, hey, no." Derek stopped moving and shook his head. He smiled faintly at Stiles. "I'm not going anywhere. I got you."

Stiles nodded back and let out a relieved breath. "You got me." He whispered.

"I want to show you—give you something." Derek said. He lifted the chain with the key over his head and set it in Stiles' hand. "Uh, it's called A Giving Key. You can buy one, and then you give it to someone who you think could use the message. They have different words on them, different sizes and colors." Derek paused. "Mine says hope. Something we could use a lot of around here. Something I want you to use. To have. To keep. My oldest brother gave this to me. I haven't taken it off since. It gave me hope when things got bad, either for me, or the people around me.

It helped when you…left for a bit. But I want you to wear it now, so that if things get bad or if you miss this smiling face," Derek gestured sarcastically to himself and Stiles laughed. "you know… you got me."

Stiles looked at the key. It was old, copper, green in some places. On one side there were four letters stamped into the metal.

HOPE

"I got you." Stiles whispered.

Stiles smiled to himself and wiped a tear with the back of his hand. He looked up at Derek and he knew… he knew he would be okay. Maybe not today, maybe not tomorrow, but he would be okay. Stiles wrapped his arms around his wolf and held tight, while Derek did the same. He silently hoped that they could stay like this until the sun came up. He hoped that Derek would never leave him to be swallowed by the dark. He hoped that one day he would be able to save himself from the darkness and leave it behind forever. He hoped that Derek would help him get there. But for now, he hoped that his wolf would hold him and protect him and keep him safe.

And of course, Derek did.