The first thing Stiles becomes aware of is the warmth against his back, the solid presence of someone and the hand pressed low on his belly. Stiles shifts backwards, unconsciously seeking the warmth from the body behind him and is greeted with a low rumble that vibrates through his chest. He blinks awake, eyes gritty and tired, the sun blinks in from the fluttering curtains as the light breeze from the open windows ruffles them.

Lips move against the back of his neck, and the hand against his stomach twitches.

Last night filters back into his mind as the body behind him stirs. Derek's shaking hands, his blank face yet eyes widened with panic. The way he looked helpless and ready to fight at the same time. How stiles hadn't known what the hell to do except hold him. Derek mutters something, lips sliding against Stiles's sweat damp skin and stills.

Stiles's own body betrays him, dick half hard from the close quarters and the warmth of a foreign body. Derek's hand low on his belly just a finger span away from where it needs to be and Stiles grits his teeth and wills his dick to calm the fuck down. This is Derek, not some one night stand that he can wake up with kisses and a hand job, hoping it will lead to more. It's Derek, Derek who broke down on him last night. Derek who trusts Stiles more than he trusts anyone and Stiles isn't taking advantage of that trust.

No matter how much he wants to.

He grits his teeth again, bites down on his tongue as that thought flitters in to his mind unbidden. You are not in love with Derek, he tells himself as he manages to extract himself from Derek's grip and slip into the poor excuse for an en suite bathroom. He rests his head against the back of the door and breathes in, willing himself not to put his hand down his pants and deal with his little predicament by himself. He bites on his bottom lip and splashes some water on his face, running his hands over his skin.

Derek's strong, self-assured and capable. Yet he's not and Stiles knows that. He forgets sometimes but nights like last night bring it all flooding back like a tidal wave as Derek crumples under the grief and guilt he carriers around on those massive shoulders. He's only seen it a handful of times but Derek always retreats afterwards, embarrassment that Stiles saw him like that evident on his face whilst he ignores Stiles for a few days.

But Stiles will be damned if he lets Derek get away with that this time. He pulls open the door to the room and finds Derek halfway out of bed with one leg into his pants.

"No you don't," Stiles warns and Derek freezes, looks back over his shoulder. "Get your leg out of those pants and get your ass back in bed, young man," Stiles puts his hands on his hips and thanks whichever deity is watching that his morning wood has gone down enough that he manages to look superior.

"I have to get…"

"No," Stiles climbs onto the bed and wraps his arms around Derek, pulls him backwards until Stiles is lying pressed to the mattress with Derek's head to his chest.

"Stiles," Derek sighs and Stiles clambers out from under him and crawls on top, pressing his palms to Derek's chest.

"No," he says again. "Morning, by the way." Derek smiles, a slow genuine smile that Stiles usually only sees directed at him.

"Morning," there's still a hint of embarrassment in Derek's eyes and Stiles leans down and presses his forehead to Derek's.

"Did you sleep?" he asks, opening his eyes. Derek looks weird this close up, blurred and doubled but Stiles can still see the crinkles at the corners of his eyes that tells Stiles he's still smiling. Derek's hands curls around his hips.

"I did…" Stiles leans back, "thank you." It's so unusual for Derek to acknowledge anything like that, that Stiles blinks, is caught off guard at the genuine tone in his voice and Derek manages to spin them both until Stiles is staring up at him with his back to the mattress again.

"You're not going to ignore me for three days now are you?" Stiles asks and Derek shakes his head, tongue darting out to wet his lips. Stiles can't help but track the movement and licks his own. Derek swallows, an audible click in the now silent room and moves an inch closer. Stiles's body flushes with heat where Derek's touching it, his mind pushing out everything other than the absolute knowledge that Derek's going to kiss him. He can't move, can't tell Derek to stop, can't tell Derek to hurry the hell up and do it already. Derek moves even closer and there's a hitch in his breathing as Stiles licks his lips again.

"Stiles," Derek says, it's quiet but shockingly loud in the still room and Derek's thumb moves against Stiles's temple. "Tell me to stop Stiles," he says and Stiles can't. Doesn't want to. Derek moves closer still, he's going blurry again and Stiles wants to close his eyes and just wait for the inevitable. "Tell me." Stiles feels the words against his lips, the brush of air from Derek's lungs.

"I can't," Stiles finds his voice although it doesn't even sound like his anymore. Derek moves, quickly like he's expecting Stiles to change his mind and wants to kiss him before that happens, and presses his lips to Stiles's. They're dry, warm, almost achingly familiar and Stiles runs his hand up Derek's arm, grips around his bicep. Derek's tongue runs along the seam between his lips and Stiles opens his mouth, welcomes Derek's tongue with a groan that he pulls deep from his belly. Derek pulls away enough to scrape his teeth along Stiles's bottom lip and then is back, with a groan of his own as Stiles shifts and gets one leg around Derek.

The angry beeping of Derek's phone interrupts rudely and Derek wrenches his mouth away from Stiles's, presses their foreheads together for a second before fumbling behind him for his phone. He rolls off Stiles and rakes a hand through his hair as he answers it.

"Hale…yes…ok…we'll be there in twenty," Derek hangs up and runs a hand through his hair again as Stiles pushes himself up right. He crosses his legs and waits for Derek to turn back to him. "We have to get to the police station," he says and turns and Stiles fixes his gaze on Derek's slick lips, parted slightly as he stares back at Stiles. "Tell me you don't regret that."

"Derek, I…" Stiles stars and Derek shakes his head.

"Stiles, iplease/i." Stiles leans forward and reaches his hand out to Derek, running his fingers across Derek's cut glass cheekbones.

"The only thing I regret is your phone ringing," he says and Derek lets out a relieved laugh that's halfway to a sob and turns his face into Stiles's hand.

"We've gotta go," he mutters and Stiles nods at him.

"I'll just jump in the shower," Derek grins at him and Stiles can't help but grin back.

"You better…you stink," Derek replies and just like that they're back to normal. As normal as they can be now they both know what the other tastes like. Stiles sticks his tongue out and crawls off the bed.

"I stink of you," he retaliates and doesn't miss the way Derek's gaze darkens right before he slams the bathroom door.

Kate Argent looks out of her room window, the sprawling grounds of Beacon Hills Institute for the Criminally Insane laid out before her. She smiles to herself and flicks her blond hair over her shoulders as she climbs down from the window ledge and lands on the floor in a crouch. Her body yearns to run, to train, to fight but the confines of the Institute make for a less than a suitable exercise regime.

Her smile widens when she hears the click of hospital regulation shoes coming down the hall and stopping outside her door. Her visitor is here.

Show time.

Stiles stares at Derek across the table in the Police station. John is talking and Stiles is half listening as he stares at Derek and tries to figure out if he looks any different now. Derek's jaw twitches and he glances at Stiles like he can feel Stiles's gaze on him. He gives Stiles half a smile and looks back at John.

"Derek's going over to see Kate Argent this morning. Erica, I want you to go with him," Erica nods, blonde hair falling over her shoulder as she does. Isaac frowns slightly at the files in front of him and puts his pen into his mouth and chews thoughtfully. "I want to know everything about every single person who has ever been to see her, or even so much as looked at her when they were there, got it?" John looks at Stiles and Stiles snaps his gaze away from Derek and nods, tapping away at a few keys on his laptop.

"I'll get Danny involved as well, four hands are better than two," John nods and turns to Scott. He opens his mouth as the Sheriff knocks once and walks in.

"Morning Sheriff," John says and the Sheriff hooks his thumbs into his belt loops and looks uncomfortable.

"There's been another fire."

Derek moves around the charred wreck that used to be the Holden family home. The wreckage still smoulders a little and every now and then a drop of water falls from the blackened beams and hisses on to something hot under them. The wreckage looks the same as the other homes, twisted bits of metal, burnt bits of wood, half charred photo albums and paintings sticking out from under singed couches and armchairs. Derek rubs the bridge of his nose. The bodies have been taken to the morgue and the Fire-fighters are still milling around, the arson expert inspecting the carcass of the house for the ignition point.

Derek didn't miss the blackened chains coiled at the base of what used to be the front door.

Four victims this time, Mr and Mrs Holden and their two boys. Derek feels bile rising in the back of his throat as imagined ghosts of their screams float up from the broken house.

Derek wants to catch this guy so bad he can taste it. His phone vibrates against his thigh and Derek ignores it, knows it'll be Stiles but he can't talk right now, let alone give Stiles what he needs which is assurance Derek's ok. Because he's not. He's so far from ok, he's halfway around the world from it right now. The phone stills and vibrates once a few seconds later and Derek ignores it again, watching the emergency services as they pack up, going back home to their families to hug the bad away. Derek hates them in that second, hates the fact they can forget this, that it'll fade into the myriad of horrors that they see, when this whole case will stick out like a sore thumb for Derek for the rest of his life, mingling into his own nightmares about his family as easily as if it belongs there. He balls his hands into fists at his sides and digs his nails into his palms, striding out of the ruins into the surrounding woods.

That's another similarity that no one seems happy to point out to Derek but he's heard John tell Stiles to look into. All the houses back onto the Beacon Hills Nature Reserve. The one his own family home was built in the centre off. The woods Derek grew up in, the tress he ran through with Laura and Cora. The trees he climbed to hide from his dad when he broke the porch swing jumping on it. The trees move, whisper to him as the wind ruffles their leaves and Derek runs his hands through his hair and pulls his phone out of his pocket. He dials his voicemail and puts his phone to his ear.

"I know you're not ok but I would be a bad…friend…if I didn't ask if you were ok. Are you ok big guy? Call me, I might have something…love you." The last two words are said quickly, like it's an afterthought, but Derek knows those words hold so much more weight than they did last night. He deletes the message and dials Stiles back, his hands gripping the phone tight.

"Hi," Stiles sounds pleased to hear from him, if a little apprehensive. Derek suppresses a smile because he can't smile right now, not when his town is suffering because of him.

"What have you got?" Derek asks without any foreplay. Stiles is silent for a second but sighs and continues to talk.

"Mark Silber has been to see Kate six times in the last three months. The first time was just before the first fire. He has a few priors, criminal damage and the like, nothing major until he was eighteen, and then he was arrested for setting a fire under a bridge where a stray dog was sleeping." Stiles pauses and draws a breath and Derek grips the phone harder, hears the brittle plastic crack under his grip.

"Where is he now?" Derek asks, his voice hoarse and unrecognisable to his own ears.

"Sending you his last known address now," his phone beeps and Derek pulls it away from his ear long enough to see the address light up his screen.

"Stiles…" He starts.

"Go find him Derek, before he hurts anyone else," Stiles hangs up before Derek can say anything else.

Beacon Hills Institute for the Criminally Insane is situated at the North edge of the town, set in sprawling grounds that are supposed to lend themselves to a therapeutic setting for the patients. It's an old brick building that looks more like a country manor than a home to numerous highly dangerous individuals.

The Director meets Derek and Erica at the door, shakes their hands and ushers them inside. The entrance hall echoes their footsteps around the marble vaulted ceiling. Isaac and Scott are off trying to find Mark Silber and Derek's skin itches to be with them instead of here waiting to see Kate.

Kate smiles over her shoulder at him, sweat beating down her spine. Derek runs his fingers across her skin and she twists out of his grasps, laughing at him.

"Where are you going?" Derek asks and Kate pulls his shirt over her shoulders, buttoning it over her breasts.

"I have a few things to do," she smiles again, her eyes lighting up with glee as she leans over and kisses him. Her kiss tastes like danger.

Three hours later Derek got the call about his family and his whole world shattered.

Derek shakes his head as the Director walks out to ready Kate.

"Derek…you with us?" Erica asks and Derek nods absently. "Do you want to sit this one out?"

"No," he snaps and then rests hand on her arm in apology, "I need to do this E."

"Ok." Erica folds her hands into her lap and stares at her nails. She looks up eventually. "If you need…anything."

"I know…thanks," he smiles at her and she grins back, a flash of brilliance and Derek feels a swell of love for the girl that has become more like a sister to him.

The Director comes back a few minutes later as Derek's letting go of Erica's hand. He gestures for them to follow and Derek sighs as he stands and strides out after him.

The halls are long in the building, rooms leading off every few feet on both sides. The occasional catcall from one of the rooms is the only noise apart from their footsteps as they draw nearer to Kate.

The Director stops and pushes the door open and Derek sees her for the first time in ten years. She looks exactly the same as she glances up from the table she's sitting at and smiles at him. It's the smile of someone who knows they did wrong but thinks it was right. The smile of someone who would kill you in an instant and he feels Erica draw away from behind him for a second before she presses herself close to his back and adds her silent support.

"Derek," Kate smiles wider, her voice sounding like she's pleased to see him, like she was expecting him and there is no one else in the world she would rather see than him. "Someone grew up in all the right places." She looks Derek up and down once and licks her lips. "To what do I owe this pleasure?" Kate gestures at one of the spare chairs around the table and the Director sinks into the background to watch the interactions. Derek takes a step forward and sits down, leaning his forearms on the table. Kate steeples her fingers under her chin and spares Erica one glance before her cold blue eyes are back on Derek.

"You know why I am here Kate," Derek says and she grins and lays her hands flat against the table.

"Do I?" She asks. "How's Laura?" She asks suddenly, cocking her head to one side. Derek grits his teeth and stares at her.

"Kate, we assume you've heard about the house fires in the town recently?" Erica interrupts, breaking Derek's gaze from Kate's face. Kate looks at Erica.

"Such a shame," she looks back at Derek, "the poor Hales…sorry, Halls," she smiles slowly again and Derek feels his fingers clench with the desire to curl around her throat.

"Can you tell us anything about them?" Erica asks and Kate looks at her again.

"What could I possible tell you? I am locked up in here," her beautiful face twists into something ugly for a second before the mask of sanity slips back and she smiles again. "I have nothing to do with them. Just a horrible coincidence."

"It's not a coincidence, Kate," Derek slams his hands against the table and everyone in the room jumps apart from Kate. She smiles like she was expecting it, like it's what she wanted. "Who's Mark Silber?" A flicker of recognition passes across her face before she shakes her head.

"Can't say I have heard of him," she answers and Derek snorts out a bitter laugh.

"Really Kate? He's been to see you six times in the last three months and you've never heard of him." Kate laughs suddenly, bright and clear and tinged with malice.

"I see Stiles has been doing his job properly," she says and Derek's blood runs cold.

"What do you know about Stiles?"

"I know you see him as more than family Derek," she leans forward and narrows her eyes at him, "I destroyed yours once I will do it again," she hisses the words out and Derek gives into the desire and reaches across the table and curls his fingers around her throat. Her eyes widen slightly in shock but then a choke of a laugh makes its way out. "Angry? Good."

"Derek," Erica's voice is insistent like she's said it a few times before and Derek drops Kate.

"You see others as more than family Derek…" Kate rubs at the skin of her throat and looks at Erica. "I would watch out for them if I were you…watch out for them like you didn't the last time." Kate rubs salt into the guilt wounds Derek carries around with him and Erica lays hand on his arm as she steps forward.

"If you're making threats Kate…"

"I don't make threats, SSA Reyes…I make promises." Kate grins brilliantly as the porters escort Kate out. She twists in their arms, her face twisted once again with malice and pure hatred.

"I will destroy you Derek, everything you hold dear…you hear me?" Kate's voice echoes down the hall and the Director steps forward.

"Happy?" He asks and Derek sweeps out of the room and down the hall before he can get his hands around his throat. The fresh air hits him as he pushes the doors open and pulls a deep breath into his lungs. His heart pounds in his ears and panic makes his hands shake as he pulls out his phone.

Erica takes his phone from his hands, taps a few buttons and put the phone to her ear.

"Boss…you got eyes on Stiles?" She glances at Derek and bites on her bottom lip. Her eyes close and she pinches the bridge of her nose. "Ok…we're on our way."

"Stiles is missing."

And once again, because of Kate, Derek's world comes crashing down.