"What do you think, Natsume?"

"Hm, I don't really–" He stops as he chokes on something, sitting harsh and dry in his throat, coughing at the sudden intake of something in his lungs. His friends pause to fuss over him, asking what happened, if he's okay. "It's alright," he tells them, "I think I just swallowed a bug," and they all pull a disgusted face before falling into conversation about times that the same thing has happened to them. He's pretty sure that's all it was, but he can't help worrying it was something else; there's a slight chill deep in his chest now, familiar to him from the few times a possessing demon has been pushed out of him, and Tanuma's look of concern does little to ease his nerves.

It grows over the coming days, stretching through his limbs and numbing his fingertips, and he thinks that maybe this isn't demon related after all. He could just be feverish, but his face feels just as cool to the touch as the rest of him, and the days wear on with him no more knowledgeable on the reason he's grown to have such trouble holding warmth, until Nyanko comes home tipsy one night and makes an offhand comment about it. "You've been fooling around with demons again," he sighs, settling down on the desk, and Natsume frowns at him.

"What do you mean?" he asks, hoping that the cat isn't drunk enough to ignore him, and his pleas are not ignored.

"You reek of them," Nyanko tells him, which is strange, because the demons have been oddly quiet of late. "You were either cursed or possessed, I bet."

Possessed. It is still difficult for him to tell when he has been possessed (cursed he has grown to recognise the signs), but thinking back to the initial feeling, it seems likely. He asks Nyanko the following morning, once he has sobered up, to try and see if he can figure out exactly why he's been needing to wear a coat indoors on a warm day. It's always uncomfortable when Nyanko looks at him thoroughly, his eyes thin slits as his energy flows through Natsume's core to pinpoint the source, but it's usually worth it.

"Netsushōhi," he says abruptly, and Natsume blinks. "A heat-eater. It's possessed you and is feeding on your body's natural heat, and will continue to do so until you stop producing it."

Natsume swallows, his hand absently going to his chest. "Until I die, you mean," he says, and Nyanko shrugs, which is more answer than anything. "Can't you force it out somehow?"

"I could," he replies, in the tone of voice that means he definitely won't, "But it's too dangerous. It's fused with your lungs and other organs by now, and purging it could cause irreversible and probably fatal damage. You're going to have to find another way to get rid of it."

He hates these, the 'find a way to fix it quickly or you die' scenarios, having been in far too many lately, but he doesn't really have a lot of choice. He either works towards fixing it now, or he freezes to death very, very slowly. He's not sure exactly how much time he has, but considering that it's already bad enough that he can't sleep after just a few days, he's sure it isn't a lot.

He is at Tanuma's house that weekend, as he usually is these days, sitting on the floor of his room with books sprawled out between them and the sun shining bright against the outside doors. Natsume definitely hadn't felt up to attending their usual study sessions, but Tanuma had stopped him after school the day before to ask if he was still going, and he hadn't had the heart to say no. He can't really focus on it, his mind wandering whenever he tries to read through his notes and his eyes blurring out the pages, until he jumps at the feeling of a hot palm on his forearm; it is the relative warmth of that hand that gives him contrast, and he shudders beneath it. "Natsume," Tanuma breathes, eyes furrowed in concern, and he knows that he has not been hiding the trembling and the pallor as much as he'd thought. "Are you ill?" Tanuma asks, mouth taut and hand now sitting like warm hearth on Natsume's own.

"Not exactly," he replies, trying not to fidget under the scrutiny, but it is difficult when movement is the only thing that keeps him going, keeps his blood flowing and gives him just that little bit of extra warmth.

"Is it one of those things?" he presses, then grimaces at Natsume's expression (shared openly, because he cannot find the appropriate words to compensate otherwise). After the typical 'you should have told me, you should have said something' conversation, Natsume finally relents and shares all he knows, which is still depressingly little, but it is at least good to have it in the open, to not have to hide it from the person he hates deceiving the most.

They spend the remainder of their day searching, wandering through the woods and asking any spirits they find for information, anything that might be able to help him (though Tanuma is not so much asking as he is lending moral support, keeping an eye on Natsume as he talks with the blurry spots in Tanuma's vision). Hours pass and they turn up nothing of consequence, and it grows colder once the sun has dipped below the horizon, too cold for Natsume to be wandering around outside, so Tanuma takes them back to his place and requests that he stay the night.

"I couldn't impose," Natsume says smoothly, automatically, but his lips tremble around the words and he has already borrowed a second coat, and there is no way that Tanuma would let him walk home in such a state (though, if they're honest, his state will not be getting any better any time soon).

"I can call the Fujiwara's for you," Tanuma offers, then Natsume sighs and says that he'll do it, heading into the hall to borrow the house phone. Tanuma watches him go with unease, inadequacy rising hot in his gut as it always does; he has finally found someone who is part of the same world, only to find that they are better at it than he is, and he never cops the brunt of it. He never had, really, his headaches and illnesses so little in comparison to how badly it has uprooted Natsume's life, and he can only wish that he had some way of helping more than a simple hand to lend.

"Trust me," Nyanko says behind him, making Tanuma jump; the thing had a penchant for sneaking up on people, and for so easily reading their thoughts. "This isn't the first time. You shouldn't get yourself involved too much."

Tanuma sighs, sitting back down in his room and laying a gentle hand on the cat's head, his thumb idly rubbing the fur. "Somebody has to," he murmurs, and he can only hope that Natsume appreciates it.

They sleep together in Tanuma's room, as they have every time that Natsume has stayed the night, but there is far more a sense of urgency, of needing to do something, now than ever before. Tanuma has set up their old space heater in the corner, months too early in the season, making the room warm and stuffy but still not warm enough; Natsume still shivers through the night, as though he were exposed to the dead of winter and not in a warm room in mid-autumn, and Tanuma hates it, hates listening to his ragged breathing and the chattering of his teeth and knowing he can't do anything, hates knowing that he's useless in this situation and so many others like it.

It is worse in the morning, Tanuma waking to find Natsume already awake and sitting with his back to the wall beside the heater, duvet wrapped around his shoulders and still shaking terribly; he catches Tanuma's gaze across the room and offers a meek smile, a good-morning wave in lieu of spoken words. Tanuma feels a little sick.

"I don't know what else we can do," he sighs, once they have both properly risen and are sitting down with breakfast. "You've asked everyone you could about it, and nobody knows anything. Have you spoken to Natori?"

Natsume shakes his head, gingerly taking a sip of the hot tea between his hands. "He doesn't know anything about this. He told me he'd ask around with other hunters."

"No need," Nyanko says suddenly, appearing from somewhere else within the house. They both turn to look at him in shock, and he takes that as his cue. "I, with my excellence at gathering information, have found a spell that should push the demon out of you."

Natsume knows that there is a catch coming, but Tanuma is not yet jaded enough. "That's great!" he beams, his whole demeanour changing. "What do we need for it?"

Nyanko settles himself in Natsume's lap as though it were his throne, and Natsume shifts a hand up to idly rest on his back. "A priest," the cat says, and Tanuma pauses. "A fairly powerful one, at that."

Natsume gives a gentle sigh, having expected something like this. Tanuma feels the hope leaving him almost as quickly as it hit. "My father won't be back for several more days," he mutters, "And I don't know any other priests here. I suppose I can give him a call and ask, but there's no way we could know if they're powerful enough."

"Natori," Natsume says, and Nyanko hums in agreement. "He's a hunter, not a priest, but he's probably close enough."

Tanuma wants to ask if they can really afford to play with 'maybe's, but they have little choice here; waiting for his father to return would take far too long, and it may very well be too late by then. He doesn't really understand Natsume's faith in Natori, but he only knows very little about the man, and he is probably the best of all the hunters he's heard of (which is very little, even despite the spirit jar incident). He would rather his father do it, but they don't have a lot of options. "Do you have his number?" Tanuma asks, and Natsume is glad that he has it memorised.

Natori is certainly not impressed when he shows up at Tanuma's house a few hours later, but not because he had been called out of work. He owes Natsume a favour or two regardless, and he's more concerned with the state the kid is in than anything else. "You've really dropped yourself in the deep end this time," he muses as he examines Natsume in the main room, Tanuma and Nyanko watching from beside them. He already knew how to use the spell they needed (he hadn't thought of it himself because he didn't know it could be used in such a fashion), so it was only a matter of getting it done now.

Natsume sits quietly and patiently as Natori prepares, shivering worse than they've ever seen but still keeping himself mostly composed, giving Tanuma a reassuring smile when their eyes meet. Tanuma feels Nyanko make a soft noise in his arms, and is glad that the cat is just as concerned as he is. The ceremony itself is pretty average for what Natori does, but it is always impressive to see, the vast spell circle painted on sheets of paper over the floor and paper charms floating through the air like birds; they rise in a segmented white ribbon and wrap themselves around Natsume's stomach as Natori chants, and Tanuma is not sure where they're going with this until Natori jerks his hand to the side, and the charms tighten in response, jerking around Natsume's stomach and winding him; he coughs once, and then he doubles over and retches all over the floor.

Tanuma takes an instinctive step forward, shocked by the sudden turn of it, but Natori holds him back. "Wait," he says, eyes narrow as he watches Natsume closely, and Tanuma turns back to see that it is not bile that has left him, but a strange, viscous blue liquid, almost gelatinous as it sinks over the floor; he watches as it begins to steam, pale blue mist rising into the air, Natsume sitting dumbfounded on the floor and staring, wide-eyed and horrified, until the last of it evaporates and Natori leaps forward with a jar, sealing the cloud inside.

The room falls eerily quiet, Natsume and Natori both breathless from the spell and the adrenaline of it, until Natori breathes a sigh of relief and they realise that it's over. Nyanko wriggles from Tanuma's arms and drops to the floor, wandering over to sit square in front of Natsume and examining him closely, making them tense again. "I think you're out of the woods," he says finally, and even he looks pleased as Natsume closes his eyes, even though it is not entirely true – while they have successfully gotten rid of the demon possessing him, it has not replenished his body heat, and he is still very hypothermic.

"I'm glad," he breathes, opening his eyes to meet both Tanuma's and Natori's gazes. "Thank you both. I owe a… a lot to you."

"I'd say we're even," Natori replies with a smile, and it is so much more genuine than what he gives everyone else that Tanuma has to wonder at it, before that smile is turned on him. "Tanuma, you should probably work on getting him warmed up. I'm going to clean this up and then be on my way. I did skip work after all."

Tanuma nods, heading over to help Natsume back to his feet and leading him back to the bedroom as Natori gathers his things, and by the time Tanuma has helped Natsume settle in and wanders back out for tea, there's no sign of him ever being there.

Natsume stays there for another two nights, catching up on homework with Tanuma now that they have the time and Natsume is far more coherent, far healthier and warmer than he has been in days and rapidly getting better. Natsume is used to it taking some time to recover from these things, and he finds himself pleasantly surprised by how quickly he's getting over this one, almost back to normal by the time he leaves late in the morning; he still has the residual feeling of the cold, but it is warm enough that he keeps his coat slung over his arm. "Thank you again," he says to Tanuma, the two of them standing on the temple doorstep, Nyanko trotting off to play with bugs while they talk. "I really do owe you one."

Tanuma smiles, arms crossed as he looks out over the garden. "You can owe me by not keeping it a secret next time," he replies, and Natsume just looks apologetic. It's a difficult habit for him to break, Tanuma knows, but they both understand that he's doing his best.

"I'll try," he beams back, and then there is a pause, birds chirping in the silence that stretches between them before Tanuma finally steps forward, putting his arms around Natsume in an action that is still unfamiliar to them both.

"I'm just glad you're alright," Tanuma murmurs, then smiles as Natsume's arms come up around his back to match him; he can feel the warmth of them through his shirt, and he is relieved all over again.