Biohazard

By Yellow Mask

Spoilers: None overt.

Disclaimer: I do not own Naruto.

Chapter 1

First Infection

Sakura muffled a sneeze with her hands as she bent over the scroll.

She'd caught a cold in Wave Country – not that she was surprised; her room had been so dusty she doubted it had been cleaned in years. There had probably been so many germs hovering around she should count herself lucky all she'd gotten was a cold.

Still, ever the optimist, Sakura saw this as an opportunity to practice her chakra healing in relation to illness. While any medic could heal injuries, only a small portion had the chakra control necessary to work with diseases. Because the immune system maintained such a delicate balance, the healer had to be very careful not upset it, as they'd end up doing the patient more harm than good.

A few months ago, Tsunade had told Sakura that she thought she had a definite future in such healing, and shoved a few of the best scrolls at her, with instructions to learn all she could.

Sakura had jumped at the chance. She had already mastered – or was close to mastering – most of the medical jutsu involved in healing injuries at the surprisingly young age of eighteen, and she'd been rather eager for a new challenge for some time.

And now, she had the perfect opportunity to practice. On herself.

Admittedly, it wasn't the most advisable course of action. The common cold – while relatively harmless to the body itself apart from a runny nose and a cough – was known to interfere with chakra-systems, making it difficult to perform jutsus.

Still, Sakura wanted to try.

To be sure she made no mistakes, she skimmed a passage she'd already memorised – a jutsu that strengthened her entire immune system against pathogens, originally designed to allow a medic to treat very infectious patients without worrying about becoming infected themselves. It was rather chakra-consuming, and so wasn't recommended for use over an extended period of time, but Sakura decided it couldn't hurt to try it, just to see if it did anything against her cold. It was designed to prevent infection rather than deal with a virus already present, but what was life without a little experimentation?

Sakura's hands flew through the seals, and she felt the warm glow of her chakra suffuse her body. It was tiring – a substantial portion of her chakra drained away like water in a bathtub after someone pulled the plug. But it should last the rest of the day, and boosting her immune system would probably help her recover from this cold that much faster.

The kunoichi glanced at the clock...and then bolted up from her chair with a curse. She was supposed to be meeting Naruto, Sasuke and Hinata at Ichiraku now!

She'd been so busy at the hospital lately that she hadn't had much time to see her friends since the end of her mission in Wave Country about a week ago, when they'd all gone out for ramen to celebrate her success. No matter how many times she told him it had only been a short, easy mission to heal a group of people whose boat had capsized, it seemed that any success, however small, was worth celebrating in Naruto's book.

The blonde had been disappointed that his friends hadn't been able to meet for so long, so Sakura had promised him she'd been able to make this lunch. She'd practically sworn on her parent's graves!

The medic shot out of her apartment and tore down the street.

-xxx-

"Hey, guys!" Sakura panted as she skidded to a halt beside the ramen stand, her words interspersed with several violent coughs. "Sorry I'm late – I got caught up in this scroll Tsunade lent me."

"Still got that cold?" Naruto frowned. "I think Hinata's got it, too – she was coughing a bit before."

As if to verify Naruto's statement, the dark-haired girl sneezed.

Sakura winced as she slid into a seat beside Sasuke. "You probably caught it from me – sorry, Hinata."

"It's o-okay," Hinata smiled, coughing a little as if to punctuate her words.

Sakura smiled a little as she caught Naruto's concerned glance towards the Hyuuga.

These ramen lunches used to be a Team 7 quirk until Sakura, Naruto and Hinata were given a mission together. Naruto had suggested going out for ramen afterwards, and had cheerfully insisted on Hinata coming along.

Sakura had seen that as a promising sign. And since then, she'd noticed that Naruto seemed much more interested in Hinata than could be explained by simple friendship. He'd begun to ask the medic what she thought of Hinata, if she thought she was just being nice to him or if she seemed to genuinely like him (at this point, Sakura had seriously considered knocking him on the head and informing him that she'd been in love with him for years).

Keen to make sure her friends found happiness, Sakura had told Hinata of these conversations, and encouraged her to make a move. It hadn't happened yet, but Sakura was nothing if not optimistic.

"So, Sasuke, how's your probation been going?" she asked.

The man next to her scowled, as though he'd swallowed something distasteful.

"That good, huh?"

She giggled a little as she twirled the noodles around her chopsticks and took a generous bite. Unfortunately, the giggles turned into a chesty, hacking cough, and Sakura soon found herself choking.

Sasuke's hand came down on her back, dislodging the food stuck in her throat.

"Thanks," Sakura grinned once her coughs petered out.

Sasuke rolled his eyes.

Sakura shook her head as she resumed eating. She and Naruto had thought Sasuke was moody and quiet before his jaunt to Sound, and when he'd returned, they'd soon learned that they didn't know the meaning of the words.

The medic felt a frown tugging on her lips as she recalled the awkward, stilted conversations that had made up much of the former Team 7's interaction in those first few months. At least, until the three of them had somehow silently reached a tentative truce. She knew Naruto was trying to be forgiving, trying to just revel in the fact that he had his friend back...but at the same time, she didn't think he could just forget Sasuke's betrayal.

For her part, Sakura had found Sasuke's return unendingly frustrating. While he had been gone, she had told herself she'd grown up, that she wanted to bring him back because he was her friend, that she wasn't in love with him anymore...

Then he'd returned, and she found she'd been wrong. She loved him just as much as ever.

It was nothing short of maddeningly frustrating. Though she kept telling herself she was older and she should know better, some part of her was still hurt by every cold glance and dismissive comment. While she recognised that Sasuke – in his own way and as much he'd allow himself to – was trying to reconcile with her and Naruto, she knew that it was only as friends; he wasn't trying to reconcile with her the way lovers did after a spat.

And Sakura hated that it bothered her. She hated that there were times when an unusually gentle or kind gesture would give her a flash of hope, only to have it crushed out again by contemptuous words. It was in Sasuke's nature to be acerbic, but the fact that he didn't seem to care enough about her to make the effort to curb his words and actions a little was rather depressing.

Sakura's nose began to run again, and she fished a few tissues from her pocket.

Sasuke watched as Sakura blew her nose, sniffling almost as miserably as Hinata was. He wondered if she was taking anything for her cold.

While his current probationary position in Konoha made for some very slow, boring days, he couldn't deny that he looked forward to these lunch meetings at Ichiraku. He could be himself around Naruto and Sakura – he didn't have to watch his words in case he offended them and they decided to report him to the Hokage and get him locked up.

And yet, at the same time, some part of him felt strangely rejected as Naruto and Sakura regaled him with stories of the lives they'd made in his absence. He knew it was stupid – if anyone should be feeling rejected, it was them – but he couldn't seem to help the irrational thread of resentment that snaked into his gut.

It took a while to admit to himself that when he left for Oto, some part of him had foolishly believed that everything would stay in stasis until he returned. That Naruto would still be eager for a spar, reveling in their competitive rivalry, that Sakura would leap into his arms as though nothing had ever happened...

But there had been nothing like that. Instead, there had been awkward silence and averted gazes, half-hearted conversations and nervous meetings. Naruto had been tentative and hesitant, and it had seemed as though Sakura was flat-out avoiding him.

It had gotten better in stops and starts, as they'd gradually stumbled and limped towards a semblance of what they'd once had, but Sasuke had never forgot the lesson those long, painful months had taught him. He had put everything on hold for his revenge, but the world hadn't stayed static.

Sakura was the prime example. She didn't stay in love with him – she moved on. She was obviously giving him another chance at friendship, but the doors to her heart were shuttered and barred and he not only didn't have a key, he couldn't even pick the lock.

There had been times when he thought she was close to saying something, when she looked at him and her eyes seemed to hold the soft light they used to all those years ago when she had been in love with him.

But she never said anything, and Sasuke told himself – repeatedly – that he had no right to be disappointed.

Though he did feel cheated. He could admit to that. Sakura had always been willing to offer him love, and when he thought he was finally ready to accept it, maybe to give some of it back...she didn't want it anymore.

Sasuke wasn't sure if he believed in god, but he was sure someone was having a cruel laugh at his expense.

"Hey, you guys are real quiet today, what's up?" Naruto chimed in, apparently having just realised that he and Hinata were conducting a conversation by themselves.

Sakura smiled. "Just thinking about something. What were you saying?"

"Hinata was telling me she's been getting a lot of missions lately," Naruto filled her in. "And I was saying you've been running yourself pretty ragged with the hospital nowadays."

"True enough," Sakura sighed, sniffling a little and wiping her nose. "I'm learning a new set of healing jutsus – ones that help the immune system."

"D-didn't you kn-know those already?" Hinata asked.

"Not really. You see, there are a lot of levels of healing, each one increasingly more complex. The first level is just your basic coagulating and splinting jutsus – stop bleedings, force broken bones to align and all that. One step above that is actual healing jutsus, when you force the skin or blood vessels or bone to knit back together. Beyond that are healing jutsus to do with organs; they tend to be more complex because organs tend to have several different types of tissues, so you have to have a pretty good grasp of chakra manipulation to repair them."

A sneeze interrupted her for a moment. "And because poison can damage so many systems in so many different ways and to so many different degrees, jutsus that deal with that are even more advanced. And finally, there are jutsus that deal with diseases and the immune system. Because the immune system varies from person to person, and because it's in such delicate balance, it takes very high levels of chakra control to be able to manipulate it safely. Tsunade told me there are only about eight or so medics at the hospital whose chakra control is at the level that they can do that – she gave me these scrolls in the hope that I'll learn these jutsus and help swell the ranks."

"Because your chakra control is really just that awesome!" Naruto exclaimed.

Sakura laughed, feeling a pleased flush rise to her cheeks. Naruto's praise was always so heartfelt and genuine that she couldn't help but be touched by it. "Thanks, Naruto."

"So if you complete the training, you'll be able to cure diseases?" Sasuke queried.

"When I complete the training, not if," Sakura said severely. "And yeah, I'll be able to help treat diseases."

It irritated her that Sasuke still seemed to doubt her abilities and determination, even though he'd had ample evidence of both. What truly frustrated her, though, was the fact that if Naruto had said such a thing, it wouldn't have bothered her – she wouldn't have taken it as slur on her abilities, because she knew Naruto respected her.

Sometimes, Sakura really hated how Sasuke could make her feel.

"Ah, Sasuke knows you rock, Sakura," Naruto assured her. "Don't take his whole bastard-ness personally."

Sasuke scowled at his bowl of ramen. He hadn't meant to imply that Sakura couldn't master that level of healing jutsus – since his return, he'd seen her heal mortal wounds beyond any other healer's ability as easily as if she were stitching up a flesh wound. He knew she was considered one of the most talented medics since...well, ever...he hadn't meant to imply...

But it seemed Sakura had already forgotten about it, as she continued to discuss the finer points of medical jutsu with Hinata and Naruto.

She didn't care about his opinion anymore – and why should she? The views and feelings of a kin-killer and village traitor counted for nothing. Sakura was friendly enough to him, but Sasuke doubted she really cared what he thought of her anymore.

"I should b-be going now," Hinata said eventually, fishing out her purse as she coughed sharply. "How much d-do I have to p-pay?"

"I'll pay, Hinata – don't worry about it!" Naruto insisted, digging out a handful of crumpled notes and dropping them on the counter. "And I'll walk you home."

Hinata flushed, but nodded as she and the blonde started down the road towards the Hyuuga compound.

Sakura was struck by the urge to squeal. Naruto was so smitten it was almost unbearably adorable.

"What are you smiling about?" Sasuke grumped.

"They're so cute, aren't they?" Sakura cooed, watching her friends' backs as they turned the corner and disappeared from sight. "Paying for her meal, walking her home...I think our little Naruto is all grown up and has fallen in love!"

Sasuke's curling lip expressed his thoughts about that concept rather eloquently. "She's technically the Hyuuga heiress, and he's the vessel for the Kyuubi. Do you really think her family will allow them to see each other?"

He was only just quick enough to duck out of the way of Sakura's fist as she aimed it at the back of his head. "Shut up, killjoy – what would you know about love?"

Sasuke frowned, and jabbed his chopsticks into his bowl with a little more force than was strictly necessary.

"I think Naruto could be really happy with her," she continued. "And you know how he is – if he decides he wants to date Hinata, no one's opinion but Hinata's is going to matter to him."

The medic smiled, leaning her chin on her hand. "It's sweet, really – Hinata was in love with him for all those years...it's nice to see her patience rewarded."

She told herself she wasn't bitter. A little envious, maybe...but not bitter.

For his part, Sasuke wondered if that was a subtle barb aimed at him, then immediately told himself it couldn't be. After all, that would imply Sakura was still in love with him.

-xxx-

Naruto smiled at Hinata as they walked towards the Hyuuga compound, wondering why the dark-haired girl had been hanging out with them lately. He'd invited her, yes, but he hadn't really expected her to agree so consistently; he figured she'd come along every now and then, not attend every ramen lunch as religiously as he and the others did.

But it was nice having her around – he'd grown closer to Hinata since his return from his travels with Jiraiya, the slow, tentative connection happening so gradually he'd barely noticed it. They'd found themselves on the same mission team along with Sakura, he'd invited her for post-mission ramen, and then he was inviting her to every ramen dinner with Sakura and Sasuke after that.

They'd talked, grown closer, and it seemed that one moment he was inviting her to the first ramen dinner, and the next, he was looking at her and thinking she was the woman he'd want to spend his life with.

But he knew she wouldn't feel that way about him. She was the first child of the Hyuuga Main House, and he was the vessel for a demon. True, Hinata probably wasn't aware of that, but she had to know he was an outcast – she had to know that he was beneath her.

Hinata coughed and swallowed, darting a nervous glance at the man beside her as she wrung her hands anxiously. She had been trying to gather the courage to ask Naruto out for several weeks now. Sakura had been encouraging her, saying that if she didn't take a chance, she'd never know, but it was difficult to swallow her fear of rejection and risk the potential pain.

But Hinata had promised herself she would do it today. She would tell him how she felt, and then...well, then she'd hear his answer.

She found herself feeling a little lightheaded, but she was determined to work through it. She hadn't passed out in Naruto's presence for nearly a year, and she was not going to start again now!

The dark-haired woman clenched her hands, set her jaw, and took a deep breath through her nose.

"Naruto..." she began, but was cut off as her chest suddenly spasmed and a storm of coughing exploded from her throat.

"Wow, that sounds pretty bad, Hinata," Naruto commented. "Maybe you should..."

His voice trailed off, his eyes growing round as Hinata felt moisture on her upper lip. She touched it automatically, wiping at the liquid she could feel collecting on her skin...and when she drew her hand back, her fingers were stained red.

"Your nose is bleeding," Naruto said quietly, sounding worried. "Why is it bleeding? Did you hit it, or-"

"I don't know," Hinata whispered, confusion making her voice soft as she felt more blood trickle from her nostrils.

She concentrated on breathing through her mouth as she mopped at the fluid with a few tissues she had stashed in her pocket.

But the blood kept coming.

"You need to see a doctor," Naruto said firmly, and she felt one warm hand grasp her shoulder firmly, steering her towards Konoha's hospital.

"It's just a nosebleed," Hinata protested, even as the lightheaded feeling progressed to a feeling of being slightly-off balance, as though she were standing on the deck of a ship caught in a storm.

"You shouldn't bleed from the nose for no reason!" Naruto insisted, stubbornly pressing her onwards.

Hinata felt strangely detached from her body as coloured spots began to cloud her vision, and long experience told her she was about to faint. "I need to sit down – I think I'm..."

But darkness descended before she could finished her sentence.

Naruto yelped, his arms lunging out as Hinata's legs folded beneath her and she lurched forward. He caught her just under her arms and yanked her to him, supporting her head against his chest as his arms kept her body from collapsing, the blood from her nose smearing on his jacket.

"Hinata!" he yelled, feelings the beginnings of panic creep into the edges of his mind. He knew instinctively that this was very different from the fainting spells she used to be known for – back then, she'd go bright red before she collapsed, but now, she'd just gone pale.

"Hinata!" he yelled again, punctuating his words with an awkward shake. "Come on, Hinata, wake up – this isn't funny!"

Hinata made no reply. Her eyes remained shut, and blood continued to leak from her nose.

-xxx-

AN: Thanks to justcallmefaye for beta-ing this chapter.