Around him, the city is quiet; sweltering in the dog days of summer and heavy with the gray promise of a storm. The sun has set but the moon is nowhere in sight. Streelights cast a golden light across the grime layered over asphalt. Within the length of a breath, a torrent of rain collapses upon him; his peacoat is weighed down and his obsidian hair cries down the severe stretches of skin that form what is now a very aggravated face. Detective Hale forces out a quiet sigh as he makes his way home.

The twenty-five cent whore screams the story to anyone in Beacon Hills who still bothers to read her; a siren song chronicling this story from the birth of a high summer to the first murder in decades, spelling out "prodigal son" and "home-grown detective" when she should call him a failure if anything at all. The sheriff called: The killer struck again. Hale's apartment is the hazy will-o'-the-wisp of a distant lighthouse in choppy seas. He signals out their code upon the door and listens as the deadbolt slides free and the lock clicks, watches the door shift open and looks upon his cheerful partner- young and foul-mouthed and fool-hardy- Isaac Lahey. The man is classically handsome; bright eyes and curly hair, with a face whose design makes it appear almost haughty, a demi-god meant to instill awe and jealously and lust. His mischief smile says, "Any leads, sir?" and Hale replies, "There's been another murder. And stop calling me sir." "Sure thing Derek," Lahey says, pulling on his tan trenchcoat and black hat. As Derek opens the door to the northern downpour, Isaac cuts off a bitter laugh and says, "Hopefully there's still some evidence when we get there."

As it turns out, there is. The flood has not succeeded at washing away all of the blood; crimson streams and lakes meander the alleyway. Under the ramshackle tent covering the victim lies most of a young woman: Her hair is golden, eyes once bright green, her fitted red Tshirt has been slashed leaving five gashes running straight down the front ending about two inches before the fabric drops off at her severed waist. He approaches the sheriff and nods curtly. "From what we can tell," the older man begins, "she was strangled, probably from behind, and the amputation was done post-mortem. The claw marks are identical to those found on the last victim-" Derek remembers the first; young boy, maybe eight, with hair like sheep's wool and eyes like sea glass, he was missing his arms and five gashes ran down the back of his red plastic rain coat- "but there's no way we can get prints in this weather and we still have no clue who she is." The sheriff meets Derek's distant eyes and the detective snaps back into focus. "Both victims were wearing red," he points out and the Sheriff nods. "Colour psychology teaches that red is a passionate colour that draws attention. It excites. Perhaps our killer is picking victims based on that." Lahey interjects, "But why is he killing people and why is he taking body parts?" The three men stand quiet, for a moment, before returning to inspection. Detective Hale glances down to the far end of the alley and catches sight of a young man wearing a red trench coat with a high collar.

He approaches the man cautiously, finding himself staring down a boy; lanky and at the tail end of a growth spurt. The boy's lips, quirked in a slight smirk, are full and bounce Hale's eyes upward past dark freckles and moles to some wide, golden eyes. "Hey kid, this is a crime scene. You shouldn't be here" he tells the boy, who pauses for a moment before replying "Sorry sir, I live just down there-" he points- "and I was curious about all the commotion." Derek Hale pauses before blurting out, "well you should head home now, kid." The boy says, "I'm no kid. But you're right, I should get home. This weather is awful." He spins on his heel and begins walking in the opposite direction, leaving Detective Hale fairly dumbstruck. He calls out, "Hey, kid!" and the kid stops, casting a "not a kid, my name is Stiles" over his shoulder. "Well, Stiles. I'd be careful if I were you. Someone may or may not be killing people who wear red." Stiles turns back to stare at Derek, nonplussed. "Thanks? I think." He offers finally, before returning his walk home. Derek returns to the crime scene, decidedly ignoring Lahey's probing stares.

The delirious fever which overtakes the city the following day slows time to a languid drip. Derek watches with vague disinterest as the hours leisurely crawl by. He is three hours in to staring blearily at the large, blank wall across from him when inspiration strikes; he makes his way downtown to the small art store and purchases the largest pieces of newsprint he can find and several colors of marker. While walking to the counter he spots Stiles in his peripheral vision picking up a can of red spray paint. Part of his mind files that away while he focuses mostly on the case.

Once back to the apartment he finds Isaac glaring lazily at a cup of coffee as he cracks the ice tray and selects several cubes to add. Isaac glances briefly over his shoulder and offers a gruff "morning" before regarding his coffee once more. Derek gets to work: Pins up the newsprint on the far wall; selects a thick, black marker and writes across it 'Beacon Hills Killer' in his thin, neat scrawl; selects a thin red marker and scribbles VICTIM ONE, VICTIM TWO; steps back to admire his work; grabs the thin blue marker and writes 'young boy, blonde, blue eyes, red raincoat, strangled, 5 slashes, missing arms' writes 'Adult female, blonde, green eyes, red shirt, strangled, 5 slashes, missing legs.'

Isaac is beside him, arms crossed across his bare chest and breathing slowly- thinking, Derek knows, can recognize- "Alright," Lahey says, finally, "So the two victims were blonde and wearing red. The killings follow an identical pattern so this is a serial killer. His M.O. seems to be; select victim, strangle from behind, add the slashes, and then amputation.. Why arms and legs? Is this a Frankenstein reference or... Why red? What was that you said about color theory?"

"Red is an exciting color that catches the eye. The red might just be because these people caught his eye. Or it may be symbolic... if this were a single murder I'd think it were a crime of passion."

"But it isn't. And so far he's killed a child and an adult, a boy and a woman. So he doesn't choose that way. But why is he taking body parts?"

Derek groans low in his throat. "I don't know." He spits out. Derek turns and heads to his room/office, grabbing the case file and posting photos under the descriptions of the victims. He huffs and retreats back to his room, reading for several hours until a knock at the door throws him into a stormy panic. "Don't worry," calls Isaac, "it's just Scott. Listen; he's even doing our secret knock." Derek would be aggravated, but he knows better than to try to involve himself in their relationship. He glances up from the notes he's been ignoring in his note pad when he senses familiar, friendly, rich brown eyes fixing him from the door. He glances over at Scott and smiles in what he hopes is a warm fashion; it causes a smile to break across the younger man's face so he counts it as a win. "Hey, Detective Hale-" Scott starts and Derek hears Isaac muffle a laugh in a cough from the kitchen- "I hope you don't mind I kind of.. invaded your secret layer or anything. I just really missed him, you know?"

Frankly, Derek doesn't know. But he can understand approximately so he shakes his head and smiles again. "It's no problem." Scott grins and bounces in place before heading for the kitchen and throwing a "thanks" back toward the room. Derek smiles quietly, to himself, before staring down the notes again and ultimately giving up.

The phone rings.

"Detective," says the Sheriff in a tone that provides no solace, "you'd better get down to Fourteenth and Franklin. Our killer struck again." Derek agrees before hastily informing Isaac of the situation and telling Scott to make himself at home. They set out quickly, arriving in minutes, and rush toward the lights. "Hale, Lahey." Sheriff greets, before nodding once and gesturing to the corpse behind him. "Little girl. Maybe seven." She's wearing a little red cardigan with five little tears in the sleeve.

"Bruising on the neck indicates strangulation pre-mortem." Lahey says quietly, and Derek affirms with a brisk nod. "Brown hair," he adds. She's missing her eyes, he notes. All the cops seem shaken by it, but Derek is the one who breaks down, heaving in shuddering breaths against the heat of tears clinging to his eyelids. Two children. Son and daughter, taken. When he rejoins the group, Lahey fills him in on the short update he missed. "Turns out the first victim was Evan Coty. Local second grader who didn't come home from school." Derek glances upward briefly, arranging his thoughts and categorizing the info about Evan. "Based on out ETD on the second victim, we should be asking members of the nightlife, what little of one there is here, if they'd seen anything." He says, to no one in particular. Lahey takes several photographs of the scene; the small and cramped anteroom of a short-lived book store, with suede-painted walls and what once was a lovely ashwood floor. The girl's lips are parted in what looks like the ghost of a gasp. She's missing her left central incisor.

When they've finished, they return to the apartment and find Scott laying passively on the couch, eyeing the makeshift whiteboard warily. He gets up when the door opens, makes his way over to the far wall, and stares at the photos of the slashes in the victim's clothing. He steps aside when Derek walks up, adds the information for the third victim, and pins up the photos. As Scott reviews this new information he sudden inhales a sharp breath and says, "Aha!"

Derek can't possibly stop his eyes from rolling, as Isaac says, "What, babe, have you put Blue's Clues together and figured it out?" Scott laughs and then says, "no. But I recognize those slashes. They look like a dog did it." This time Derek manages to restrain himself from laughing out loud, but only barely. "Yes, Scott. A dog did this." He says, dismissively, before he eyes the marks again. A quick internet search proves that Scott is, indeed, right. The claw marks are decidedly canine. But what does that mean for the killer?

Scott shrugs and says, "I told you, I do work for a vet you know. I don't know what it means. I used up all my thinking power for the day. I'm going to bed." Isaac follows, casting Derek a pre-apologetic look. Derek groans and leaves the apartment, sets out for a good walk. The heat of the day has left the night sky cloudless; it has fled the sidewalk and blacktop and left behind a bitter chill. He pulls his black peacoat together, buttons it against the unexpected cold, and wanders downtown. His eyes are restless, roving the dirtied streets with suspicion verging on paranoia. A newspaper says, "third murder in two weeks," says "murders bring Beacon Hills to its knees, heatwave boils blood." Derek stiffens. He knows what boiled blood smells like.

He realizes that he's arrived at the scene of the second murder, the alley dark and still stained madder with a woman's blood. There is a hissing noise and Derek glances quickly around the corner only to see Stiles, spraying the red paint across the bricks. He's still wearing that bright red trench coat, despite the warning. He approaches and glances at the wall as he says, "Stiles... you know that's against the law, right? Why are you doing that? Here?" While depressing the can and forming the shallow stroke of a final quotation mark, Stiles drops his head onto his left shoulder and regards Derek with vague disinterest between full dark lashes. "Yes, I'm aware of the law. I'm bored." He finishes the sentence with a tired pout, and Derek turns his attention to the wall temporarily.

"Elle avoit vu le loup."

"What does it mean?" Hale asks, not expecting an answer. "Dude, they have google for a reason" is the one he receives. "Well you're still breaking the law." Derek says, though he doesn't mean to say that at all. "Well excuse me," Stiles begins, "are you placing me under arrest? Can you place me under arrest?" "No." Derek replies, to both counts. "Well then," Stiles continues, "I'll just go be bored at home, then." For some reason, Derek calls after him, "Do you know anything about what's going on?" and Stiles stops, turns, and says "she was a prostitute" before leaving. As he walks away, he drops a small and neatly folded piece of white paper. When Derek picks it up, he sees that it contains seven numbers written in the same hand as the graffiti. He smiles, and then promptly panics and returns to the apartment.

Unsurprisingly, Scott is there. Him and Isaac are sitting on the couch, grasping at each other while a horror movie plays on the laptop. Derek says, "aren't the murders we're trying to solve scary enough?" Isaac chuckles, replying, "we're finding inspiration. We thought about the case the whole time you were off brooding and we're just stumped." Derek steps into the bathroom, regarding his reflection with disdain. He meets his own peculiar eyes; jade and blue and gray depending on the light but always with a corona of rust surrounding the pit of his pupils. He stares at his unkempt face for a few moments, before sighing loudly and returning to the living room, taking a seat on the couch next to Isaac as the credits begin to roll.

Derek pulls the computer to his lap; responds to Isaac's complaints with meticulous irreverence. Google tells him that 'Elle avoit vu le loup' is an antique French slang term for a women losing her virginity, and suddenly the clue is even more cryptic than before. His phone rings. "Hale," says the voice of the sheriff, "so far we can't find any connection between the kids or their parents. We know that the second victim was a prostitute who went by the name Yours Truly." Derek relays the info to Isaac and then says "I don't think there is a connection. I think he's just hunting."
"Hunting?" the Sheriff questions. "A friend of ours, a vet, looked at the claw marks. They look decidedly canine. I think our killer is carrying out some sort of animalistic roleplay, but I don't think he's killing people based off of anything specific; he's hunting and the red catches his eye." Derek can hear the sheriff relaying that to a few officers before he says "Good work Hale. I don't know how you do it, getting into the mind of killers." The sheriff hangs up and his parting comment leaves a sour taste in Derek's mouth. Scott looks over at him from his seat and says, "I'm a friend?" while his face splits into a smile. Isaac laughs and says, "I told you he couldn't be a grump forever" while Derek contemplates his taste in partners.

That train of thought leads him to think about Stiles, about the number he left and whit it means. Then Isaac interrupts his reverie by asking "alright already Great Grump Detective. Who is she?" Derek's head snaps to the right; one eyebrow ascends in a question and Isaac lets loose a chuckle.
What? Not only am I an amazing detective who you hand-picked and stole from the police academy but I've been working with you for three years and living with you for two. You think I can't read you like a book?"

Derek laughs at that because while it may all be true, Isaac's misread the most important detail. Then Isaac amends, obviously catching on and reminding Derek why he chose the younger man in the first place, "so who is he then?" Derek pulls his phone and the scrap of paper from his pocket, eying it wearily. Isaac huffs. "You're 25," says the curly-haired cherub of a man, "and you're choosing now to have your gay crisis?" As Derek stares at the phone in his hand, dial tone loudly reminding him that he hasn't even managed to hit a single button, he forces out, "it's not a crisis." Lahey snorts dismissively in response, rolling his bright eyes and sinking further back into the couch, doodling absently on the notepad that they should be using to figure out this case. Instead, the only thought Derek can grasp; which is singing loudly in his ear, which is beating a constant beat against his skull; is of that damn boy.

After ages Derek dials the seven digits and almost hangs up immediately. Stiles answers after two rings, quietly muttering, "hello?" "Stiles." Derek says simply. "Oh," replies the tinny voice filtered through static, "hey detective. I was wondering when you'd call. How's the case going?" Derek stays silent for a minute before mumbling, "that's why I called you. I think we're on to something but you seem to know more than you're letting on. We should meet up so you can tell me just what you know, how you know it, and why." Stiles laughs as the muffled rumble of a truck crawls by. "Are you asking me out on a date?" he asks and Derek coughs, spluttering out a quick "no! This is not a date. This is a... business meeting." Stiles laughs again, tells Derek to meet him downtown, and hangs up. Isaac glances over with practiced nonchalance as Derek hangs up the phone. The act breaks as a chuckle rips from him and chases Derek out the door. On his way downtown, Derek fumes.

When he finds Stiles, it's outside a small coffee shop. He's wearing tight-fitting black slacks and that same red trenchcoat- collar buttoned up to his chin against the breeze. His military-style boots bark out muffled bangs as he approaches Derek, smirk twisting his face and bright eyes affixed to Derek's own peculiar eyes. "Well hey there, grumpy. Nice to see you too." Derek glares, but then allows himself to smile softly. "Tell me what you know," Derek says, and Stiles glances around, shakes his head, and indicates Derek to follow.

He leads him into the coffee shop and toward the counter. "I'd like a tall black drip and my friend will have..." Stiles says, prompting Derek to add his order. "Tall americano." Derek supplies, before they walk to a pair of overstuffed twin armchairs; weathered black leather straining at the seams. They orbit the chairs clumsily for a few minutes before sitting in silence. When the barrista brings them their coffee and shuffles away, Stiles' eyes turn dangerously serious and seem to deepen in colour to resemble honey rather than gold. "Tell me what you know," he mumbles, and Derek begins. "The killer is targeting people wearing red who otherwise have no connection. He leaves canine-esque claw marks on them after strangling them from behind. I believe he is acting out some sort of roleplay and is making a show of hunting like an animal. He wanders the streets at night and seeks out victims. He's smart, probably highly educated and informed about or trained in police procedure." Derek punctuates his explanation with a long pull of coffee. It's bitter. He quirks an eyebrow at Stiles, who nods encouragingly.

"Very good, detective. You're almost spot on." Stiles sits back and smiles, drowning the elaboration he's clearly itching to give with a sip of his own drink. "Well...?" Derek pushes, but Stiles just shakes his head. "If you want anything more out of me," Stiles says, "you'll have to convince me why I should help you." His eyes sparkle, mischievous. Derek thinks that Stiles' eyes would be better fitting for Loki or Eris than this young man. Derek says "fine then. Come with me." And stands up, abruptly leaving the cafe and leading Stiles to his home. Isaac looks mildly amused when they arrive, says, "well this relationship is moving along quickly," causing Derek to growl out a harsh "shut up."

Stiles observes the information they've compiled so far before pulling a pen from his coat pocket. He adds several notes in his thin scrawl. He names Evan Coty as 'the lamb' and Yours Truly as 'the whore' and the little girl he identifies as Lucille Troy, labels her 'the virgin.' In a blank space, to the right of Lucille, he writes 'Fourth Victim,' writes 'adult male' and 'savior.' Derek expresses his confusion. Stiles glances over as if it should be obvious, and sighs. "The killer is acting out a story in his own twisted way." Isaac seems dubious, but merely says, "so he's ill?" Stiles responds with a non-sequitur framed as an aside: "It's never lupus!" The detectives are stumped but from Isaac's bedroom comes Scott's warm laughter. "You're not really helping all that much." Isaac says, and Stiles feigns offense. "Let's see you solve the case yourself then," Stiles says defiantly.

"How do we know you're not the killer?" Isaac says, "you sure seem to know a lot about this case." Stiles actually laughs at that, says "you really think I could be the killer?" Isaac looks to Derek for a moment before answering, "no. I don't. Because Derek trusts you, and I trust Derek's instincts. Most of the time." Derek looks over at him and says "oh gee. I'm touched." Stiles lets loose an overwrought gasp and points at him. "So you can be funny! I thought you were just grumpy all the time." This earns him a chuckle from Isaac and Derek wonders why everyone is surprised he's angry most of the time when he lives with Isaac Lahey. "So, about the case..." Derek begins but Stiles yawns loudly, checking the time on his phone before swearing loudly. "I have to get home" he rushes, grazing Derek with his burning eyes and saying, "Good luck on the case detective. Be careful out there. Tomorrows a full moon and you know what they say about crazies and the full moon."

About an hour later, Derek is laying in his bed and glaring at the ceiling. It won't answer the questions he's screaming out in his head so he glares harder. His door opens slowly and Isaac peaks in and says, "for the record, I like him." before retreating and leaving Derek to stew in his utter chagrin. His phone rings. "Hale," says the detective. "the fourth victim was just found two blocks from your apartment." His heart thunders in his ears and, doubtful he'll be able to even hear the answer of the roar of blood, asks "give me a description." "Young man, maybe twenty. Red coat. Black pants. Short hair." Derek bolts from bed and pounds desperately on Isaacs door before fleeing the apartment half-dressed in a red dress shirt and boots and boxers, coat slung over one arm and trailing behind him.

"Stiles." his mouth says. Chanting it like a spell "Stiles. Stiles. Stiles stiles stiles stilesstilestiles." When he reaches the police tape he vaults over it; there's an exodus of oxygen from his lungs when he sees the body. Dark hair shorn to stubble coats a head punctuated by unfamiliar features. Derek gasps in and shoves out a ragged sob. He composes himself and catalogues the relevant details mechanically: Adult male, red jacket, five slashes on his right leg, missing his ears. He operates in a fugue that only ends when he's walking away from the scene and calling Stiles, leaving an annoyed Isaac behind. "Derek?" questions Stiles. "Thank god. Oh my god. The killer got someone and the description the sheriff gave me sounded like you and I was so scared where are you?"

Stiles laughs for a good four minutes. "I'm at home, like an intelligent person would be in the event of a serial killer stalking the city. Where are you?" Derek glances around, orients himself, and tells Stiles he's near the coffee shop they went to earlier. "Meet me there." Stiles says, smile bleeding into his voice. Derek goes to meet him.

He stands outside the cafe for about five minutes before Stiles walks up, red trenchcoat like a beacon. As the boy approaches Derek grins wildly. Stiles says "Did you really panic when you thought I was dead?" and Derek feels his cheeks warm with a slight blush. "Yes."

"Have you figured it out yet?" Stiles smirks, haughty, and Derek feels his eyebrows twist into a glare. "No."

"And to think," Stiles says, "the paper called you the prodigal son." Derek grins again, says "shut the fuck up" fondly before gripping Stiles by his face and dragging him in for a kiss. Their lips meet and Derek groans; Stiles tastes like clove. Like autumn. Like crisp air at dawn. Stiles parts his lips and licks a stripe across Derek's, forges inside when Derek pants hot against his face. Derek's fingers try to tangle in hair that's too short before throws them around Stiles' waist inside his open coat. He runs his hands down the ridge of Stiles' spine and shudders when Stiles grips his lip in his teeth, pulling back and smiling and the sky. "My, what big teeth you have." he deadpans and suddenly Derek jerks back, awed. "I figured it out. He's the big bad wolf. It's so obvious how did I not see it before." Stiles chuckles in response, says "seriously though. How did you need that much coaching? Aren't you supposed to be good at this?" Derek smiles, sheepish. Says, "I was a little distracted." Stiles smirks again, parts his lips to retort when Derek says "shut the fuck up." They kiss again.

Sitting on Derek's couch, Stiles says "Now I don't know who it is yet. But I have a list of suspects. I saw them near the crime scenes and tailed them. They all happen to be pretty shady people but I don't have enough on any of them to really put it all together." Derek smiles and wonders if he'll ever stop being amazed by him.

They wake up to Isaac making breakfast in the kitchen behind them, tangled together on the couch. A thin blanket has been draped across them, and when Derek meets Isaac's eyes the bastard winks before turning back to his bacon. Over coffee, they discuss the suspects and agree to split up and tail the three likeliest suspects.

The plan goes more horribly than Derek would have hoped. Derek and Isaac gain nothing from their stakeouts but Stiles never meets them back at the apartment. The fourth try calling Stiles phone, an unfamiliar man laughs for a minute before hanging up.

When the man calls back, they begin tracing the call. It turns out to be superfluous, though, as Stiles' voice brokenly offers the address before instructing Derek to come alone. "Or else." says the man. They set out. Derek folds his hands into fists and cuts into his palms with his short nails, clenches his jaw so tight his head aches, and wills himself not to fail.

They pull up to a cabin in the woods and it's just as creepy as Derek had imagined: Painted black with red trim and a crimson door. "Stay here." Derek orders, before exiting the cruiser and approaching the building cautiously, gun in hand. The door swings open easily, and Derek steps into the front room and sweeps from corner to corner, heavy gun raised and ready. There's a muffled bang from the closet, and he cautiously advances. He opens the closet door and a bound Stiles falls into him, and slides to the floor. Derek sets down the pistol and rips the gag from his mouth. "Behind you," says Stiles.

Derek stands and turns in one motion, sees a tall man with a wolf mask hiding his features and black clothes blending him into the shadows. "I told you to come alone." The man says, says "you should have listened." He raises an axe and goes to strike before the air is cut with a loud crack. The bang echoes thrice before dying; the murderer blinks twice before dying. In the doorway stands Isaac Lahey. Derek turns back, dropping to his knees and tearing at the ropes around Stiles. When he's freed, the young man stands up on shaky legs and lets a laugh loose. "I was honestly a little concerned that I was going to die. No offense." Derek smiles and pulls Stiles into a rough kiss. A throat clears behind them, and Stiles freezes. "Oh. Hi... dad." He says and Derek turns around to see the sheriff looking entirely unimpressed. Derek looks back and forth several times between the men before he pales, turns to Stiles and says "Dad?"

Isaac laughs.

Epilogue

Derek bends down, pulling the lasagne from the oven and carrying it to the table. He sets it down, sitting across from the sheriff- John. Isaac sits to his right, looking as if he can't decide which to eye with more hunger; Scott, sitting across from him, or the pasta. Stiles walks in and sits to his left, placing a quick kiss on his cheek before starting to serve everyone. John smiles, a little, and Derek revels in the moment. Scott, unsurprisingly, ruins his revery by asking "So Stiles. How did you and Derek meet again?" Derek groans desperately, dropping his head to the table, while Isaac and John laugh loudly. He feels Stiles place a hand on his shoulder and say "Well, I was snooping around a crime scene..."