At around ten o'clock that night, Stiles slid into the passenger seat of Derek's Camaro. "The lack of streetlights makes you even angstier than usual. You should lock your doors." He paused at the look on the sour wolf's face. "What, you didn't know I was here? Seriously?"

"I knew," Derek muttered, and if his tone was a little defensive, well, then Stiles' night just got figuratively brighter. "I could smell you. But you're not supposed to be here—I told you to stay home."

They were in an older part of Beacon Hills, surrounded by brick buildings and old factories and R-rated bookstores. The Camaro was parked on the side of the road in a row of other cars—a gleaming black jewel among some serious rust buckets. Stiles had left the Jeep a couple of blocks away, because people recognized it as belonging to the sheriff's kid. He wanted to avoid that, in case… of what, exactly, he wasn't sure.

"No, you told me to stay inside and do my homework and try not to die." Stiles started ticking off points on his fingers. "I did my homework—and most of Scott's, by the way—I stayed inside, except for the last hour and a half or so, and hey, I'm not dead yet." He tried to find a comfortable position in the low-slung car and kind of succeeded by sitting on his legs. "So, really—"

Derek's hand snapped out suddenly, reaching over and grabbing Stiles by the front of his jacket. His voice rose in irritation. "How long have you been wandering around by yourself?"

"Ow ow ow," Stiles half-yelped, bruises pulling taut alongside sutures. He was regretting not taking that painkiller before he left, even if he probably would've wrapped his Jeep around a tree at some point if he had. "Long enough to gag at the nightmare that is Scallison and to referee a trash ping-pong match between Erica and Boyd, and pop in on Isaac—"

Derek had him pulled in so close that they were breathing on each other and fogging up the windshield. Derek smelled the same as earlier, except for some more sweat, and hey, that really wasn't all that bad. Great, I like the guy's sweat… what's next, his foot fungus? God I hope he doesn't have foot fungus.

Derek released his grip on Stiles and looked like he didn't know what the hell to do when Stiles didn't retreat back over the gearshift. Finally, with a mix of curiosity and trepidation, Derek asked, "How did you know where I'd send them?"

"It was easy to figure out. The park's where this mess—" Stiles gestured with flapping hands at himself, "—happened, so you'd want someone to hang out there even though you don't expect that the harpies have made a literal nest in a tree. But I told you about the narc, so you couldn't send Scott with Allison because that'd get back through the gossipy cops to the Argents, and you couldn't send Isaac because he's a fugitive, and you probably don't want another bad touch from the law, so you sent Erica and Boyd. I figured you'd keep Isaac at home—seriously, man, trolley cars, really—and I went over and said hey-howdy. Then Scott texted me and said that he and Xena Warrior Princess are necking out in the woods. Any other burning questions?"

Derek's mouth twitched, almost as if he did have some burning questions, and that made Stiles feel… tingly. So tingly, in fact, that he almost missed it when Derek spoke again, quieter, "How did you know where I would be?"

Stiles sputtered a laugh. "Dude, you brood a lot. Brooding is best done in the dark. Ergo, the darkest part of town that isn't the woods. The car's also kind of a giveaway. A beauty, but a—"

And then Derek put a hand over Stiles' mouth and made a shushing noise, which was borderline ridiculous, like a babysitter waving a finger at an errant child, but only if that babysitter was hairy and had on-demand fangs and claws and fur.

Clearly Derek had heard something over Stiles' babbling, so Stiles shut up and tried to ignore how his palm felt against his lips. Which was very hard to do, because then Stiles started thinking about how Derek's… other things might feel on or in his mouth… wait, serious and probably deadly situation, not the time for that.

They stayed that way for almost a full minute, and then Stiles couldn't stand it anymore. He licked Derek's hand to get him to let go, plastered on an eager expression, and whispered, "What is it, Lassie? Is Timmy in the well?"

Derek stared at him for a long moment. "Stiles."

"Yes, Derek?"

"Do you have a concussion?"

"No, why—"

Derek cuffed Stiles upside the head and got out of the car. "I didn't want to risk any more brain trauma—that one cell is lonely enough as it is. Let's go."

"Funny. You're a funny man." Stiles rubbed at his head and glowered as he followed Derek down the street, keeping to the shadows. He glanced around, saw nothing out of the ordinary, and asked, "Which building? And why am I with you again?"

"The old cannery with the tuna billboard. And you're with me because…" Derek paused and cleared his throat. "Because I need to check this out and there's no time to get any other backup."

They were close to the warehouse in question, and could see that its metal sides were deformed and warped by time and abandonment, that there was glass missing from all the windows—the whole clichéd nine yards. It was adorned with a mural of a smiling tuna, which looked less like something you'd want to eat and more like something you'd want to kill with fire. A half-collapsed chain link fence failed to look intimidating or keep anything out.

There were no signs of life, at least not to human senses. At the time, Stiles thought he'd have nightmares because of the demented-looking fish—there would be nightmares, but they wouldn't be the tuna's fault.

The two of them were crouching behind some trashcans near a homeless person that was definitely dead.

Stiles resisted the urge to gag. "You sure know how to make a guy feel special—this is more charming than the rotting birds thing. What did you hear, anyway?"

"Wings. I heard wings. Like feathers ruffling." Derek sounded reluctant to use a word like ruffling.

Stiles contemplated that as they dashed across the street, to approach the building from what had once been the office entrance. "Could be a seagull."

"We're not near the ocean and it'd have to be a seagull the size of a fucking rhinoceros," Derek said. "Now shut up and stay behind me."

The door opened with some nudging, creaking on rusty hinges. The place was a dump on the inside—what had once been a secretary's desk was now a sad-looking mass of rotted wood; a schedule that was never going to be fulfilled took up a wall; some fluorescent tube lights hung crookedly down from the ceiling. It smelled like mold and dirt and expired fish.

Derek's boots crunched on broken glass and trash and old beer cans, followed shortly by Stiles' sneakers. They went down one hallway and then another, passed bathrooms and a fire exit, and then pushed through some double doors onto the factory floor.

Stiles was in the middle of saying "do you smell something burning" when Derek shoved him in the chest so hard he fell and landed on his ass and skidded a couple of feet away. He felt stitches snapping and his body screaming and blood starting to flow. Smoke was pouring out from behind the canning machines and a bunch of guns were going off and Derek was getting shot, multiple fucking times, blocking the bullets from hitting Stiles because he was just laying there, fragile and human and screw that.

Stiles scrambled back to his feet as Derek fell forward, through-and-through holes in his torso leering and losing blood. Stiles caught Derek's dead—no no no, not dead—weight and locked his knees, swearing with the effort but managing to keep them both upright. The thunder of the guns had been deafening and now Stiles' ears rung as the assholes in the factory paused to reload.

He started shuffling back the way they came, muttering, "Come on, big guy, this way." It was like trying to manhandle a bleeding life-sized Ken doll.

Stiles could feel his own blood soaking through his shirt, his chest and back flaring with pain, but he was more aware of Derek's blood sliding slick between his fingers. He managed to stick close to the wall and get them around the corner and had time to think that this trap hadn't been for them, and that whomever was behind it hadn't seen through the smoke, didn't know Derek wasn't the harpy… yet.

Chris Argent's voice echoed from behind them: "Hey, birdie! Why don't you just give up? We're going to catch you, you must know that—your roost is toast and your flock is next!"

And the hunters started laughing, like it was a joke instead of part of a horror show.

They made it around the next corner and were three steps from the fire exit when Derek's clutching hands were able to pull them to a standstill.

"Stiles," he rasped out, blood dribbling down his chin, coating too-sharp teeth bright red, features wincing as his body tried to heal. "They're going to be waiting outside, there's too many of them to outrun. Leave me here, maybe you can get away—"

"Oh, you are not pulling that crap on me," Stiles said, and rammed his shoulder into the emergency door, barreling outside as an alarm started blaring.

Of course, there was a guy waiting with a rifle on the other side of it; Stiles held Derek up with one arm and smashed his fist into the asshole's face. He went down and they kept going. Luckily the Camaro wasn't parked that far away, but neither were Argent and his crew—Stiles heard engines start seconds after they got outside. He hustled Derek down the street, suddenly glad for the lack of streetlights; the sky was cloudy, making even more in the way of shadows, so if there were any snipers around their job would be much harder.

Stiles thought it was interesting that Chris Argent found the mysterious harpies to be more important than werewolves on the full moon, and then Stiles wondered how he had time for all these thoughts while he was running for his—pardon, their—lives.

When they neared the car, Stiles started feeling Derek up, saying, "Keys keys keys—where are your goddamn keys?"

Derek stiffly removed his keys from the right-hand pocket of his jacket and lurched for the driver's door.

"Oh no, nope, not happening," Stiles said, grabbing the keys and popping the passenger door. "Get in, I'm driving."

Derek growled even though he was in no shape to be intimidating. "Over my dead—"

"Hey, you let Scott drive that time—fuck me!" Stiles saw five pairs of headlights making their way to the street from behind the cannery, coming fast.

Luckily Derek wasn't a complete idiot and relented, getting in the car and slamming the door behind him. Stiles slid over the hood of the Camaro and got behind the wheel, shoving the key into the ignition and making the world's ugliest K-turn to get the hell out of there.

They headed back towards town with three cars in formation behind them—two of them broke off down other streets and Stiles knew they'd be back to try and box them in. He was hoping the Camaro's speed would be enough to beat them, since it seemed all hunters drove SUVs.

There was blood on Stiles' hands, on the steering wheel, everywhere, stinking up the car with its copper tinge. He risked a quick glance at Derek and asked in a tone that was a little too high for his liking, "Those weren't wolfsbane bullets, right?"

Derek grunted, then remembered to use his words. "No," he answered through gritted teeth, "I got shot six times—if they were wolfsbane bullets I'd be dead by now. I don't know what the fuck they are, but they hurt like a bitch."

"How are you still talking?"

"This has happened before, moron—drive faster!"

Stiles pushed on the gas. His eyes flicked down to the speedometer, which was climbing higher and higher, the Camaro's engine roaring like it was in pain. The headlights were still behind them, and as they blew through a four-way stop, Stiles knew it would be a matter of seconds before Argent attempted to have them cut off. "I'm going to do something with your car that you're not gonna like very much."

"You touching the damn wheel's enough to give me an ulcer—just do it."

The needle was hovering around 90. Stiles exhaled and took a blood-crusted hand off the wheel to curl around the gearshift. The next intersection was coming up fast, and a concrete divider appeared on the driver's side, to serve as a barrier to keep someone turning from the left side from crossing four lanes of traffic. This was a busier intersection even at the late hour. The light was changing from yellow to red as they approached, and Stiles waited until the last possible second, just before the opposing traffic surged forward—

He slammed the Camaro into a different gear and jerked the wheel, making a sharp U-turn around the end of the barrier. The back of the car fishtailed, but Stiles was used to the Jeep doing that and rode it out, slowing down as they merged with traffic. He watched Allison's father's red SUV try to U-turn the barrier and fail, the boxy vehicle landing on its side. Horns blew and tires squealed.

Stiles whooped. "I am awesome! God, he had that one coming." He looked at Derek again, slouched against the leather seat, drenched scarlet and looking very pale under the streetlights. His brain caught up with the situation. "Derek? I thought you said you got shot six times."

Glassy, vulnerably human eyes shifted to meet his. "I did. Say that."

"But I only see four holes." Stiles flailed around when he realized what that meant and that he was the only person around to do something about it, kind of like that thing with Derek's arm that seemed like it had happened a lifetime ago. "Oh God, oh shit, the other two are still in there?"

Derek looked down at himself, looked at the red pool he was sitting in, and nodded once. "Yep."

"Crap—guess we're taking a trip to the vet."

The next morning, Stiles had another brush with death when Derek jumped unannounced into the Stilinskis' tiny-ass laundry room through the window.

Stiles didn't notice until he turned around and bam, werewolf! "Oh my God, Derek!" he exclaimed, and then slapped a hand over his own mouth, praying like hell his dad hadn't heard him. Through his fingers, he hissed, "You need to stop doing that, or I swear I'm going to misappropriate a taser and shove it someplace the sun doesn't—"

"Are you okay?" Derek interrupted, and he sounded… concerned? Without being growly? Was that even a thing?

"Did you have a stroke after I dropped you off last night?" Stiles retorted, in a tone that didn't match his words or his bewildered expression. "You actually sound less dog and more human—be still my beating heart."

Ah, there was the requisite snarl of the day. "I could make that happen, if you want." There was no threat behind Derek's words, and that certainly wasn't normal. He rubbed a hand over his face—the guy looked pretty damn tired, probably from healing—and asked again, slower, in case Stiles couldn't understand him because he was mentally deficient, "Are. You. Okay?"

Stiles sprayed one of his dad's shirts with stain remover before dropping it into the waiting washing machine. "I'm good, man. After we took care of your little, ah, problem, I might've noticed my blood loss and had Scott take me over to the hospital. Again."

Scott had met Stiles and Derek at the veterinary clinic—okay, wait, no, back up, he didn't meet them; he got there fifteen minuteslate. Which in a sort of life-or-death situation wasn't comforting, at least to Stiles. Thankfully he'd had the forethought to copy a key to the place months ago, mostly because Scott was constantly losing his own.

Stiles was in the middle of pulling the first bullet out of Derek when Scott finally showed up—he was late because he had to take Allison over to the hospital, where her dad was being treated for minor injuries from a car accident. Huh. It turned out it didn't matter when he got there, because all Scott ended up doing was puking in the bushes outside and offering moral support while Derek tried to not rip Stiles into shreds or scream his lungs out.

As soon as the second bullet hit the tray, Derek had roared—an agonized sound, so much worse than the car's engine—and jumped out a window like the wild thing he was.

Stiles had wondered out loud what it would be like to ride on his back like he was a pony and passed out, much to Scott's panic and chagrin.

Now, Stiles picked up a pair of his jeans, dumped them into the washer, and tried to forget about the feel of cold metal forceps in his hand. He tried to forget about the sound of muscles squelching and spreading, knowing he was causing someone pain, specifically causing Derek pain, hurting instead of helping.

Stiles was kind-of-not-really-oh-yes freaking out, and the thing he was best at while freaking out was talking, even if nothing he said made sense. He was looking anywhere but at Derek and talking faster and faster with every word, barely pausing for air. "No big deal, not really. Scott's mom sewed me up again, like the cupcake she is, and force-drank me—is that a thing, force-drinking, like force-feeding—orange juice and promised not to tell my dad about my second visit if I promised to stop shredding myself up like cheese on a grater. Those were her actual words and there were a lot of food-related analogies in there. Are you hungry? I'm hungry."

"Stiles." Derek moved the laundry basket on the floor between them to the side with his foot, and put his hands—huge yet fascinatingly careful—on Stiles' shoulders. "You're rambling."

Stiles blinked, catching his breath and wondering why the hell Derek's presence had gone from freaking him out to calming him down in like, 2.8 seconds. "You think so?"

"Just a little." Derek was closer, suddenly, and it wasn't surprising—there was no such thing as personal space around this guy. His expression changed, smoothing out into something Stiles hadn't seen before and barely had time to wonder what the fuckbefore Derek said, "Thank you. For last night."

Stiles blinked again—holy shit, he's grateful—and his mouth flapped a couple of times before he could find some words. "You're, uh, you're welcome. No problem." He poked Derek in the ribs, touching a shirt that he knew had smooth, unblemished skin underneath, like some kind of miracle. "You owe me, though." Even though you saved my life first. "And if I'm making you a sandwich—because you look like you need a sandwich and a nap—I'm so going to own your ass."

"All right, so I get the hunters setting the warehouse on fire—the smoke provided cover for smell and sight, and it also destroyed where the harpy was staying. The noises I heard were prerecorded—they had to be if this was a setup—maybe to make her think someone was moving in on her territory." Derek had torn through his first ham-and-cheese-on-rye and was working on another. "What happened to the bullets?"

Stiles choked on potato chips in his flailing journey to get to his desk, because he actually had an answer for that one—sort of.

They were eating in Stiles' room, because his dad might've been essentially immobile and drugged to the gills, but he wasn't deaf. Now probably wasn't the best time to try to re-introduce him to the sour wolf… who wasn't being so sour anymore. Personality revamp or not, he was pretty sure his dad would try to shoot Derek on sight, and Stiles was officially done with people shooting Derek.

Stiles finished chewing, dug through all his homework, and found the Tupperware container with one bullet in it. He grabbed his plate and trekked over to Derek.

Stiles sat down next to him on the bed—close but not touching—and said, "I gave the other one to Scott, which he's supposed to give to Allison at school today. She's going to check her parents' armory and see what matches." He opened the container and held the bullet in his hand; it looked like the last bit of a melted candle, if somebody squished it with something heavy. "They're hollow-points, obviously, custom dum-dum rounds for a .308 rifle—maybe a Saiga, more likely a Winchester. It doesn't really matter what kind of gun it was, the damage is the same." He paused for dramatic flair.

Derek looked exasperated and said through a rather unattractive mouthful of food, "But there's something weird about these particular bullets."

Stiles rolled the deformed bullet between his fingers. "Yeah, and I don't know how to describe it." He moved closer, managed to wait and not stare openly as Derek swallowed, and then held the round up to the light and pointed. "You see those little tooling marks there? At least what I think are tooling marks, since I'm making this crap up as I go?"

Derek nodded. "What do you think it means?"

"I think the Argents modified these bullets specifically for harpy hunting. I'd need to see one that's intact, but it looks like they're designed to suction in on themselves during impact. Like, imploding instead of exploding, the opposite of what most people would want a bullet to do." Stiles made a face. "That's part of the reason why you bled so much; there was no shrapnel, but anything that the bullets tore through had the blood directed out the open wounds behind them, like an irrigation system."

"All of the lore we've read so far associates harpies with air," Derek said. "In fact, the main theme in killing them is strangulation. They fly, they're avian creatures, so air is essential to their power and strength—it's a trigger. Like the moon is for us. Let's say there's something in their physical structure that's different from ours, dependant on air—if you take that extra air away, or replace it with something else…"

"It probably wouldn't kill them if they can heal like you guys do, but the effect would be enough to slow them down, make them weaker." Stiles let out a strained laugh. "This is so messed up."

Derek snorted. "What else is new?" He went very still. "Your father's moving around downstairs."

Stiles sighed the sigh of the long-suffering and stood up, grabbing their empty plates to take with him, but leaving the bullet behind. "Probably trying to save some of his masculinity and make the adventurous trek to the bathroom on his own." He was out the door, but stuck his head back into the room to say, "Y'know, you don't have to poof while I'm gone. You can, uh, hang out here, or meditate, or whatever the fuck it is you do when nobody's looking. I'll be back, and maybe I'll bring cookies."

Derek didn't hang out or mediate while Stiles was gone. He held the bullet between his fingers—still warm from Stiles' touch—and tilted his head, thinking.

Planning.

Checking to make sure there were no immediate threats, Derek placed the bullet on the nightstand and kicked off his boots. He laid down and shut his eyes. And if he was curled up like a harmless puppy on the mattress when Stiles came back and he practically heard the kid grinning, well, it wasn't like it was going to happen again. He had a reputation to keep.