Warnings: rated M for descriptions of physical violence, injury, and illness.

Spoilers: up to 1x09, 'Po'ipu', then goes AU during that episode.

Note: the story title and chapter names come from the Cat Power song 'Werewolf'.

Chapter 1: 'Once I saw him in the moonlight'

Crouching on the living room floor next to Steve, Danny holds his gun with one hand and gestures at Steve's arm with the other. "What the hell?"

"I got shot, Danny," Steve says, fashioning his torn shirt into a bandage to stem the bleeding. That fucker Nick Taylor had fired while Steve was on the phone with him, grazing Steve's right arm just below the intricate tattoo. So far, so familiar; Danny had received a practically identical wound on their first day of working together.

But Danny's bullet graze hadn't given off acrid black fumes. He's pretty sure he would have remembered that.

"I'm aware you got shot; I saw you get shot, which is all too common an experience for me these days! No, I'm talking about the weird-smelling smoke coming from your arm right now."

Steve is acting calm enough, movements methodical as he gets the Molotov cocktails ready, but his eyes are wild and he's broadcasting 'don't fuck with me' vibes. The bleeding cut on his forehead makes him look even more savage.

"Can we deal with this later, Danny? Because in case you hadn't noticed, my house is still under siege from highly-trained men who want us dead."

Danny says, "We will definitely revisit this topic, Steve; count on it." He shakes his head slightly in the hope of clearing it. "Okay, so Kono and Chin are covering the upstairs and we're on firebomb duty. What's next?"

Steve grins, crazed and dangerous and beautiful, as he outlines the plan. Then they launch their counter-attack.

In the end, it comes down to Steve and his former friend on the beach, fighting with knives. Danny watches from inside the now-secured house, using a pair of night vision binoculars he'd taken off one of the dead guys. Danny's too far away to get a clear shot at Taylor, and he can't risk distracting Steve by getting any closer. So he waits, and prays.

The two of them are moving so fast that Danny can't quite follow what's going on. It feels like watching a really good fight scene in an action movie, except that it's Danny's partner out there and they're not using plastic knives that retract on impact.

There is something strange about Taylor's weapon, though. It's a dark night, but the gleaming blade is visible to Danny even without the binoculars; Steve's steel knife doesn't have the same shine to it. Taylor's blade looks like it's made of silver, and why the fuck would he be carrying something like that?

Danny winces as that shining knife slices across Steve's left arm, and Steve ends up on the sand...oh God, things are looking bad for him. But somehow Steve gets the better of Taylor, and shoots the bastard dead. Danny sends silent thanks heavenward, and leaves the house at a run.

Down on the beach he finds Steve ready to collapse, tears in his eyes and blood streaming from a gash on his bicep. Danny can't see if there's smoke coming off the wound, but the tang of the ocean breeze can't disguise that same nasty burning smell as before.

And then HPD are all around them, too late to be much help, and paramedics escort Steve away. Danny stays, along with Chin and Kono, to oversee the handover of General Pak and his family and to update the relevant authorities on what's happened. By the time he leaves, well after midnight, CSU's already examining the scene and all the scattered bodies.

Christ, Danny thinks as he drives home, how many more people are going to die at the McGarrett house? He doesn't think Steve's the devout type; still, it wouldn't hurt to get some kind of priest in there to cleanse the air.

It's late the next morning before Danny sees Steve again. He could have easily slept all day, catching up after the stress of the General Pak case; it's a Saturday, and he doesn't have Grace this weekend. But he's worried about Steve, who was not only wounded last night but also betrayed by someone he'd once trusted with his life.

Sometimes it's difficult for Danny to gauge the level of concern and affection for Steve that he can safely show. Danny wants so much from him, wants to give him so much, that it takes effort to keep himself within acceptable parameters.

Steve's his teammate and friend, so Danny figures that gives him the right to stop by and check how he's doing. That's what he would've done if something similar had happened to Marco, his partner back in Jersey. But Danny never pictured Marco while jerking off.

He has another reason for visiting Steve this morning, though. No matter how he feels about the guy, Danny's a detective first and foremost. And he can't turn off that instinct which leads him to notice, remember, and seek explanations for unusual occurrences.

Thinking about those weird injuries had kept Danny awake last night, long after exhaustion should have claimed him. So he's formulated a mental list of questions for Steve (first up: 'Seriously, what the hell?').

He forgets them all once he gets to Steve's place, lets himself in, and sees the devastation in daylight.

The house is in a bad enough state, but Steve himself looks terrible. He's lying on the couch under a blanket, eyes open but unfocused. It looks like he slept here – if he got any sleep at all, which seems unlikely from the dark circles under his eyes. His tanned skin is gray, his lips bluish, and he's sweating despite the cool breeze coming in through the broken windows.

Danny sinks to his knees beside the couch, his parental side taking over. He reaches out to feel Steve's forehead, avoiding that cut above his right eye even though it's nearly healed already.

Steve's burning up, skin clammy; when Danny feels for his pulse, he finds it's racing. The scariest thing is how Steve's just lying there, in his bullet-riddled childhood home, letting Danny touch his face and throat without threatening to break his fingers. He's never seen Steve so listless.

"What's wrong with you? You should be in the hospital," Danny says. "Come on, get up, I'll drive you over there right now."

Steve looks at him with bloodshot, shadowed eyes and scoffs weakly. "Forget it. They wouldn't know what to do with this."

"What the fuck are you talking about? You've obviously got some nasty infection from Taylor's knife. Either he forgot all the rules about keeping weapons clean, or he deliberately coated the blade with something toxic just to mess you up."

Steve shakes his head, but doesn't offer an alternative explanation.

"Let me see what that bastard did to you," Danny orders. Steve hesitates for a long moment before relaxing his death grip on the blanket, and Danny pulls it back to expose his bare torso. He doesn't stare at Steve's chest, or glance down at the black boxer-briefs that hide very little. Danny's not a creep; he wouldn't take advantage of a mostly-naked sick friend like that, even if said friend is ridiculously attractive.

The paramedics had bandaged both Steve's arms, but the gauze dressings are now stained dark with blood. Danny pulls out the pocketknife he's started carrying at all times – 'always be prepared' is a damn good motto when Steve McGarrett's your partner – and carefully cuts the bandages off.

He can't help sucking in a breath at what he sees. Danny knows from experience what a bullet graze and a knife gash should look like the next day, and this isn't it. Although blood is still seeping out, it appears that the damaged flesh has mostly knitted itself back together. Even with the help of stitches, Steve has healed remarkably fast.

But the skin around both wounds is blistered and blackened, as though it's been burned, and that strange bitter smell still lingers.

"Steve," Danny says urgently, "something's seriously wrong here. You need help, babe."

"No!" Despite Steve's fragile state his voice is loud, and so vehement that Danny involuntarily takes his hands off Steve and sits back on his heels.

Steve bites his lip and then goes on, calmer but still insistent. "I'm telling you, Danny, I know what this is. And there's no cure but time. I just have to sweat it out, and sleep it off."

"Okay, so, what is 'this' and what's causing it?"

"Silver," Steve says quietly.

Danny blinks at him. "Wait, silver is bad for you? I saw some late-night thing about it boosting your immune system. The way the infomercial hosts were talking, it's a magic bullet."

Steve's laugh has a strained edge to it. "Yeah, you could say that."

"So explain the problem to me, then," Danny demands.

"Nick used a silver bullet to shoot me, and a silver knife to stab me."

Huh. Well, Danny had seen that odd gleaming blade of Taylor's for himself. And CSU had called him this morning, reporting that one of the bullets they'd found embedded in the living room wall had been different: shinier than the rest, and definitely not made of the usual materials. They were sending it for analysis, although results wouldn't be back until Monday at the earliest – the lab was short-staffed at the weekend.

Five-0 usually got priority lab access, but Danny hadn't insisted in this case. It had hardly seemed time-critical, since all the bad guys were dead and General Pak's plane was already in the air.

"Okay, I believe you," Danny eventually says. "But why would he do that?"

Steve shrugs, but Danny can tell he's faking ignorance. "So you're allergic to silver and Taylor knew?" he presses. "Or, what, did he think you're a werewolf or something?"

Most people wouldn't catch the way Steve momentarily flinches, before his expression goes blank. But Danny's able to read his partner pretty well by now.

He knows he just struck a nerve; he also knows that Steve's verging on a total shutdown. Danny won't get anything else out of Steve today. And the harder he pushes, the less likely it is that Steve will ever open up to him.

"I told you, man, you gotta choose your friends more carefully," Danny says, with a lightness he doesn't feel. "Ol' Bullfrog must have been bugfuck crazy, to mistake your silver allergy for a sign of lycanthropy."

'Yeah, I guess," Steve says, then looks at Danny with surprise. "Wait, how come you know that term?"

"Lycanthropy? It turned up in the 'word of the day' desk calendar Grace gave me last Christmas," Danny explains. "What, you hadn't noticed my ever-expanding vocabulary?"

"You do use an awful lot of words," Steve says, smiling slightly. Though he's clearly still in pain, the tension in his body seems to have reduced.

It's a start, Danny thinks.

"Okay," he says briskly, "have you showered since last night?" Steve shakes his head. "How about you go take one now? It'll make you feel better, and these wounds need cleaning before I can re-bandage them."

"I'm not sure I can manage the stairs," Steve admits, and that's more weakness than he's ever allowed himself to reveal in their months of working together. Danny feels stupidly flattered.

"No problem – I'll help you. I'm stronger than I look, you know."

"I know exactly how strong you are," Steve says. Danny doesn't know how to take that, so he just stands up, reaches for Steve's hands, and pulls him off the couch. Steve sways on his feet, and Danny wonders if it's from exhaustion, hunger, or this supposed allergic reaction. He'll try to get Steve to eat something before putting him to bed.

Going slowly, Steve's right arm slung across Danny's shoulders, they make it across the living room and up the stairs. Danny loses count of the bullet holes he sees in the walls en route. Jesus, it's going to take a lot of work to get this place back in shape. At least someone cleaned up the broken glass last night, so Steve's bare feet won't get cut to ribbons.

They make it to the bathroom, and Danny parks Steve on the side of the tub as he runs the shower. He's not at all surprised to find that Steve's soap is the non-perfumed, anti-bacterial kind – that should help.

"You probably shouldn't wash your hair for a few days," Danny suggests. "It'll just pull at your stitches. I speak from bitter personal experience, trust me."

"I do," Steve says, meeting Danny's eyes. Danny glances away, discomfited by that earnest look.

"Can you take it from here?"

Steve nods.

"Try not to fall over," Danny says, and closes the door behind him. He could go downstairs, maybe find something to read, but he needs the time to think – and he wants to be nearby in case Steve needs help. So he sinks to the floor outside the bathroom, and rests his head against the wall.

He can believe that having an allergy to silver is a real medical problem; people seem to be allergic to every last thing, these days. He can also believe that Nick Taylor came back from Afghanistan less than sane. Danny had gotten a bad feeling about the ex-SEAL from the start, and the way he'd deceived, taunted, and then tried to kill his old commanding officer was pretty damn psychotic.

Taylor could have observed Steve's reaction to silver, at some point, and developed some fucked-up theory about the reason for it. So: 2 + 2 = 4, right? The guy was a delusional shithead, and poor Steve is now suffering the consequences.

And anyway...even if werewolves are real, Steve can't be one. Danny pulled an all-night stakeout with him, just a few weeks ago. It was a beautiful night, with no clouds to hide the full moon. He clearly remembers spending the long hours swapping stories with a human being, not a howling monster.

End of story.

Except – no. All Danny's instincts are telling him that there's more to it. He's certain of two things: that his partner is hiding something important from him, and that hearing the word 'werewolf' had made Steve flinch for some reason.

Danny's pretty sure about a few other things, too. Steve's healing quickly, abnormally so, but his skin still looks weirdly charred. Danny's sister used to get allergic contact dermatitis as a teenager, until she figured out which cosmetics preservative caused the problem. She'd complain that her skin felt like it was on fire, yeah, but there was definitely no burning or smoke involved.

He's handled enough arson cases to recognize the stench of seared flesh; he's seen the dead in every state of degradation and decay, and probably knows all the odors a living human can produce. The smell coming off Steve's wounds is different – sharper, somehow.

Danny cannot come up with an explanation for all of this that makes a lick of sense.

The water shuts off in the bathroom, and Steve opens the door a few minutes later with a towel wrapped around his waist. He looks slightly better, although still dangerously pale all over, and blood is trickling from his knife wound.

"Time to patch you up again, and then you need more sleep," Danny says, getting to his feet. "Where's your first aid kit?"

Steve rubs his eyes, looking for a moment like a tired little boy. "Kitchen – under the sink."

"Okay, I'll go grab it. Head to your room, and put on whatever you usually sleep in."

Steve just nods silently and walks down the hall, leaning on the wall for support. God, it's freaking Danny out to see him be so obedient.

Danny goes down to the kitchen to get the supplies. While he's there, he grabs a bottle of water out of the fridge since Steve is no doubt seriously dehydrated. He also takes a few moments to fix the snacks Gracie always requested when she was sick: peanut butter on crackers, and peeled carrots cut into sticks.

And yeah, maybe it's weird that Danny's thinking about Steve the way a parent would. But he needs someone to take care of him, and there's nobody else left to do it.

Danny goes back upstairs to find Steve lying on the unmade bed, wearing only pajama pants. His eyes are closed, but he doesn't exactly look peaceful; he's sweating and shivering.

Steve opens his eyes as Danny enters the room. Despite being so out of it, the sharp senses that have kept him alive thus far are still working. Danny sits on the edge of the bed and pulls on a pair of latex gloves from the med kit.

"Do you need any special topical stuff to treat the allergic reaction?" Steve had said he recognized the symptoms, which probably means this – whatever this might be – has happened before.

"Plain antibiotic cream is fine," Steve says.

Danny cleans the wounds out, dries them, dabs the ointment on, and applies new dressings. The whole process must hurt like hell, but Steve grits his teeth, clenches his fists, and barely utters a sound.

"Thanks," he says when Danny's done. "You're good at that."

"I've been on so many first aid courses that I could probably teach one by now," Danny jokes, peeling off the gloves. "Plus, I'm a father – I've patched up plenty of boo-boos in my time." He always kisses them better, too, though he doesn't mention that to Steve.

"So, you think you could eat something or are you too nauseous?"

"I am hungry, yeah," Steve says, sitting up gingerly. Danny reaches over to prop the pillows against the brass headboard, then lays the plate of snacks on Steve's lap.

Steve picks up a cracker liberally covered with peanut butter, and smiles a little. "My mom used to fix me these when I had to stay home from school."

"Yeah, mine too. It's a universal panacea, I guess, like chicken soup."

Steve's stomach rumbles, and Danny grins. "Oh, is that a vote for chicken soup I hear? 'Cos that could be arranged. My great-grandma's recipe is a family secret that I am forbidden from ever writing down. Seriously: when Grace is old enough, I have to teach her in person 'til she knows it by heart. But since I'm in a charitable mood and you're so sick, I'm willing to make it for you tonight."

"That sounds amazing. Honestly, though, I'll be fine. You don't have to stay and look after me," Steve says, not meeting Danny's gaze.

"Yes, I do – you're my partner. If you won't go to the ER like a sane person, then you're left with me as your nursemaid." Danny pauses for dramatic effect. "Want to reconsider your decision?"

"I think I'll stick with you, even if the hospital nurses are prettier." And yeah, Danny can't argue with that. They've spent so much time at the Hawaii Medical Center, either getting treated or waiting around for victims or witnesses, that Danny has created a mental top ten of the hottest nurses working there.

Well, actually, he has one list of female nurses and one list of male nurses. Danny's an equal-opportunity ogler.

When Steve's done eating, Danny takes his plate. "You want some painkillers? I got Advil and Tylenol here."

Taking the Tylenol bottle from him, Steve swallows twice the recommended dose. Danny's first instinct is to stop him, because he would never let Grace do that. But he reminds himself that Steve is an autonomous adult, and has somehow survived this long despite being a reckless idiot much of the time.

"You should get some rest now," Danny says as he stands up. "I'm gonna head out and pick up the ingredients for the soup. Do you need anything?"

Steve nods, his eyelids already drooping. "There's a few things on the grocery list stuck to the fridge, if you wouldn't mind getting them too."

"Okay, I can do that. What about the drugstore – anything there that would help?" Danny's fishing for information, yeah, but he's also making a genuine offer. Steve shakes his head, and yawns widely.

Danny rearranges the pillows so Steve can lie down, then reaches out to lay his hand on Steve's forehead again.

"Damn, you're still running one hell of a fever." Steve shivers under his touch, so Danny pulls up the comforter and tucks it close around him.

Steve murmurs, "Thank you, Danno," and closes his eyes. Danny stands there for another few seconds, looking down at him. It takes a lot of effort to turn around and leave the room.