Iruka was woken by the sound of the door closing. At first he thought it might be Kakashi coming back – he'd left with Sandaime a little while ago and never returned – but when he looked up groggily towards the doorway he registered the deep auburn of Kaede's hair.

"Iruka-sensei," she said, and as Iruka's vision focused he could make out the shocked expression on her face. "I just got in and heard about what happened."

She picked up the notes at the bottom of his bed and scanned through them rapidly. Beside Iruka, Naruto was still curled up on the bed. He'd also fallen asleep and Kaede's entrance hadn't woken him.

"Have you seen the seals?" he asked.

"Yes, they were sent to my office. I recognised your base symbol for blood right away, but I didn't think you were anywhere near the testing stage yet. You never told me you'd started seal development, let alone completed one!"

She hooked the notes back onto his bed and stared at him, her expression torn between amazement and distress. Iruka smiled, hoping to comfort her.

"It was pure luck," he confessed. "I'd been playing around with a blood loss prevention seal and had a pile of chakra paper in a drawer beside the bed. I'd never even tested it, I was just hoping it would work. The theory seemed sound and I didn't have time to doubt myself."

Kaede moved to sit on the chair that Naruto had occupied earlier. "Unbelievable."

Iruka laughed softly and winced at the pain it caused. "I'm even more thankful now for all the help you've given me. Without your guidance, I wouldn't have got this far with my research. I may need to put my work on hold for a little while though."

"Well, of course. Your medical notes look good and your recovery should be fairly quick, but you shouldn't push yourself." She paused and reached up to push a lock of hair behind her ear. "Iruka-sensei, I hope I'm not being insensitive for asking after practical matters, but are your research materials in a safe place?"

"It's all hidden in my room," Iruka reassured her. He wondered if the sealing scroll containing it all was now soaked in his blood. Hopefully nothing inside it had been damaged.

"It's not that I don't trust you to have left it somewhere safe," Kaede said, "but it's highly classified material. Since you'll be in the hospital for a few days, maybe you should tell me where it is and I'll keep it in my office until you're well enough to resume working on it."

"It's inside one of the pillowcases on my bed," Iruka said sheepishly. "If you could move it, that would be for the best."

Kaede nodded. "I'll see to it later. Now, Iruka-sensei, if there's anything I can do to make your stay here more comfortable, please don't hesitate to let me know."

"I think I have everything I need for the moment. But thank you for asking."

"I need to get back to work, but the offer stands indefinitely," Kaede said, standing up and pausing near the door. "Get better quickly, Iruka-sensei. You don't belong in a hospital bed."

Tenzou exited the hokage's office and just stood for a moment in the corridor, trying to piece his thoughts together. The 3am Killer was ANBU. Sandaime had already compiled a list of all current and former male ANBU operatives particularly skilled with genjutsu – a list that Tenzou thankfully wasn't part of – and Tenzou had folded a copy of it into his notebook to read in detail later.

Sandaime had asked him not to interview Iruka yet, worried that it was too soon after the attack for Iruka to relive his experience with someone dressed like his assailant. He'd related to Tenzou what Iruka had already told him, however, and Tenzou's initial reaction had been much the same as Kakashi's. ANBU was more than an elite security force, they were a tight-knit community. ANBU operatives were only allowed to reveal their membership with one person outside of ANBU, and that person had to be a close family member or a romantic partner of more than three years. Many ANBU didn't have anyone who qualified, and so the only people they could talk to honestly about their lives were other ANBU. To Tenzou, certainly, the bonds of trust between them were sacred.

But now Tenzou would have to investigate his own, shaking the foundations of that trust in the process. But he would do it, not least because Sandaime had helped him to take a step back and look at the situation more logically. It was true that wearing an ANBU uniform didn't necessarily mean the killer was currently serving in ANBU, but stealing a mask and uniform would take an extremely high level of skill and cunning. ANBU gear was stored in the organisation's offices, which took up a whole floor of the Hokage Tower and weren't accessible through either of the main stairwells. The entrance to the private ANBU stairwell, as well as the windows on the floor itself, were sealed with powerful wards that only responded to the chakra signatures of serving ANBU members and the hokage. Even the village council couldn't access ANBU's base of operations.

With these security measures, there were only two options for a potential thief: to disable the wards through the method known as 'lock picking', which used a justu that called for incredibly fine chakra control and was time consuming even when done right, or to influence a current ANBU member to commit the theft. The first option Tenzou could dismiss without even thinking about it. If the wards were ever disabled for more than five seconds – more than long enough for someone to pass through a door – alarms would go off, alerting every ANBU in the offices that there was a security breach. Once wards were picked, the intruder couldn't activate them again, making this a foolproof system, and Tenzou would know if the wards had been forcibly disabled recently.

The other option was that the killer wasn't ANBU but had an accomplice, willing or otherwise, who was. ANBU weren't immune to genjutsu or other advanced methods used to control a person. But, even assuming that you didn't have to know an ANBU's identity to target them, former ANBU were much more likely to know enough details of the offices' security to come up with a plan that ensured their accomplice wasn't caught.

Sandaime had explained this reasonably and patiently, looking no happier than Tenzou was at the path the logic forced them to take. Chances were high that 3am was ANBU, former or current. There was nothing to be done but accept it.

The silver lining was that Iruka's testimony narrowed Tenzou's field of possible suspects from practically the entire village to a list of twenty-seven names. The obvious place to continue his investigations, in light of this development, was the ANBU equipment room.

Before he could reach the private stairwell, however, he ran into an obstacle. Kakashi was loitering by the stairwell door, and he stood up straighter when he saw Tenzou.

"I've been looking for you," he said.

To those who knew the signs, Kakashi was visibly upset. His hands were jammed in his pockets to prevent him from fidgeting and betraying his agitation, and his posture had changed from a lazy slouch to the confident bearing he'd held himself with during his ANBU days.

"How's Iruka-sensei?" Tenzou asked cautiously.

This was apparently the wrong subject to choose. "I wouldn't know. Try asking someone who's allowed to see him."

"You're on the list." It should have been obvious. Kakashi was a clear fit for the profile. In fact, if Kakashi wasn't one of the few people Tenzou would trust with his life, he might have re-categorised him from a witness he wanted to interview to a person of interest.

"Are you leading the investigation?"

Tenzou paused. It wasn't exactly a secret, considering the number of people he'd already spoken to about the case, but he knew where this conversation was going and the last thing he needed was a personally invested jounin trying to pump him for classified information.

His silence must have lasted a beat too long, because Kakashi scowled at him.

"I know you're investigating the serial killings. At Iruka's house you said there'd been no seals on the other two victims. You wouldn't know that unless you'd seen the bodies or the case files."

Sometimes it was tiring how sharp Kakashi was. They didn't call him a genius for nothing.

"I can't talk to you about the case," Tenzou said wearily.

"Do you think I did it?"

"No."

Kakashi nodded, as though he'd already known he was above Tenzou's suspicions.

"I'm going to help you solve this."

And this was exactly the sort of conversation Tenzou had been hoping to avoid.

"Senpai, you can't hijack an ANBU investigation," he said, trying not to sound patronising. "You don't have the clearance, and even if you did, your friendship with Iruka-sensei makes you emotionally compromised."

Kakashi was clearly expecting this argument. "I'm not asking you to show me your case files. Just tell me who to watch or talk to and I'll give you the information. My relationship with Iruka-sensei will only motivate me to work harder."

"You say that now, but I know you. You'll find some compelling reason why I should give you more information, and then you'll whine and plead and call in favours I don't even owe you –"

"Tenzou, I'm serious about this. I'm going to investigate this with or without you. You can either keep an eye on me and speed up the whole process by giving me some solid leads to follow, or I can go solo and waste everybody's time going over the same shit you've already looked at."

Tenzou glanced around to make sure nobody had overheard Kakashi mention his name while he was wearing his mask. That was the kind of careless slip Kakashi would never usually make, which did nothing to raise Tenzou's confidence in him. However, he knew that Kakashi wasn't making idle threats. Left to his own devices, God only knew what kind of damage he could do.

"Fine," Tenzou said reluctantly. "You can help me out, but if anyone asks, you're acting on your own. I won't let you compromise this investigation, Kakashi."

Kakashi nodded seriously. "What do you need me to do?"

The ANBU equipment room was at the back of the building. The window, like all of the windows on this floor, was covered with wards that not only restricted entry but also made the glass opaque when viewed from the outside. From the inside, the sunlight passed through uninhibited, lighting up the room.

Tenzou had sent Kakashi off with his notebook and told him to read through it. The case files were restricted documents and not even Kakashi could persuade Tenzou to show them to him, but Tenzou's own personal notes were technically at his own discretion. It was a fine line, and Tenzou could already imagine the hokage's disapproving face if he found out, but he wasn't showing Kakashi documents beyond his clearance level. Technically.

The equipment room was where ANBU armour and weapons were kept, as well as materials used on missions such as chakra paper, sealing scrolls and chakra wire. It was a general storage area for everything except the office stationery, which had its own cupboard down the hall.

The masks were kept in a cupboard at the back of the room. Masks from former ANBU members were kept for three years, in case of a return to service, after which time they were destroyed and had to be recreated if the ANBU decided to return. Blank masks were used for certain training exercises as well as being on hand for new recruits.

Tenzou switched on the monitor of the computer by the door. The screen already showed the equipment logs. Every piece of equipment had to be checked in and out of the room, and records were saved on the computer for a year before being uploaded to one of the servers in the records room. There was a security camera in the corner to make sure no one simply helped themselves to weaponry without checking it out.

According to today's logs, there should be seventeen unpainted masks, of which five were currently checked out for training purposes. Tenzou printed the logs for the two weeks prior to Akane's death, although he doubted he'd find anything worth following up. 3am couldn't have been stupid enough to check the mask out under his own name.

Before he left, Tenzou counted the masks in the cupboard. There should have been twelve. He was completely unsurprised to find that there were only eleven.

Kakashi's wards were down, and Tenzou wondered if it was intentional or a further sign of Kakashi's distracted state. He knocked, and heard Kakashi shout for him to come inside. The door was unlocked.

"You should be more security conscious, senpai," Tenzou scolded as he entered, removing his mask once the door was shut again behind him.

"It'll only make things easier if the murdering bastard comes to me," came the answer. Tenzou rolled his eyes.

Kakashi was sitting in the living room, his legs crossed beneath him on the couch, vest discarded and hitae-ate removed, although his left eye was currently closed. Tenzou imagined he'd been using the sharingan to memorise the contents of his notebook.

"Have you finished reading my notes?"

Kakashi gestured for him to sit down. "What's this bullshit theorising about someone picking off disrespectful chuunin?" The disdain was thick in his voice.

"I was using the word I thought the killer might use," Tenzou explained. He lay his mask down on the coffee table and wiped away the thin sheen of sweat that always formed on his upper lip when he wore it on a warm day.

"You think Iruka-sensei was attacked because of what he said to me."

"I can't ignore the possibility. I'm not saying it was your fault."

"I picked a fight with him," Kakashi said, staring fiercely at the opposite wall. "I could have handled it differently, but I chose to make a scene. I'm such a fucking idiot. Why is he even friends with me?"

"Maybe he doesn't mind you acting like a fucking idiot every once in a while," Tenzou suggested.

Kakashi snorted and threw him a knowing glance. "You say that like someone speaking from experience."

"I'm friends with you because I have endless patience," Tenzou said seriously, and was relieved when Kakashi laughed.

"Did you find anything in the equipment room?" Kakashi asked.

"There was a mask missing, but that's what I expected to find. I took a print-out of the logs but I haven't had chance to go through it yet."

"I'll do it."

Tenzou gave him a stern look. "You can't look at any documentation from the offices. You know that, Kakashi."

Kakashi sighed but didn't try to argue. "So what can I do?"

Tenzou thought about it. "You and Iruka-sensei are very close, aren't you?"

"Fairly close. I mean, pretty close. I mean, yeah, I guess so."

Tenzou raised an eyebrow but otherwise ignored Kakashi's sudden ineloquence. "This argument you two had yesterday, is there any possible way it could be related to the Hyuuga clan?"

Kakashi stared at him for a long moment. Tenzou waited it out.

"I noticed in your notes that you're a bit hung up on Hiashi," Kakashi said. "I didn't see him there yesterday, but there was probably at least one Hyuuga hanging about. I think Hiashi's daughter is in Kurenai's genin team."

Tenzou snatched the notebook back and flipped to a page titled Why Them? Beneath it he'd circled the name Hyuuga and around it summarised Hiashi's connections to Eri and Akane. Now he added another branch, writing Iruka's name with suppressed excitement.

"The argument with Eri-san was about Hinata too," Kakashi said, making the same connections as Tenzou. "Iruka-sensei was really just concerned about Naruto, but to someone who didn't know that, he was saying that none of the nine genin on the rookie teams were good enough for the chuunin exams. The Hyuugas are definitely proud enough to be offended by a slight like that."

Another thought hit Tenzou.

"Hang on a second." He pulled the list of ANBU operatives from his pocket. It was more than his job was worth to show that to Kakashi. Scanning the names, he made a pen mark beside three of them.

"How many Hyuugas fit the profile?" Kakashi asked.

"I can't tell you," Tenzou muttered automatically. There was one current ANBU on the list and two former. Hiashi himself hadn't made the cut – Tenzou wouldn't be surprised if he'd once been ANBU, but his genjutsu skills clearly weren't up to scratch – but Tenzou hadn't seriously considered that the Hyuuga clan head was going around murdering chuunin. He may well be giving the orders, but it was more likely that another clan member had gone rogue. That didn't mean that Hiashi wasn't aware of what was happening, though.

"If I send you to speak with Hiashi, will I regret it?" Tenzou asked.

Kakashi lit up at the prospect of action. "Absolutely not. Is he on the list?"

"I can't tell you who's on the list. Stop asking."

Kakashi started pulling his vest back on. "What are you going to do while I'm gone?"

Tenzou folded the list back into his notebook and put it away. "Look through the equipment room logs, first of all. Then go out and start chasing down ANBU."

Kakashi winced. He understood the ANBU bond of trust and what it meant that Tenzou had to break it down.

"Meet you back here in two hours?"

"You better not be late."

Sasuke and Sakura had given up waiting after two hours that morning. They were used to Kakashi being late, but Naruto was usually on time. At half past nine, Sasuke had suggested that they start training by themselves, still half expecting Kakashi to eventually turn up with some tall tale about why he couldn't stick to his own damn schedule, but when noon rolled around and they were still the only ones on the training ground, it was clear that nobody else was coming.

Sakura flopped down on the grass and leaned back against a tree. "Do you think Kakashi-sensei actually had the nerve to cancel the session and not bother to tell us?"

Sasuke sat down next to her, jamming a kunai back into its holster. "Why would he tell Naruto and not us?"

"Probably just to mess with us."

Sasuke couldn't argue with that.

They sat in silence for a while, recovering from their latest bout of sparring. Sasuke could feel the pulse of chakra from the other nearby training fields, and he was idly watching two chuunin practising taijutsu not far from them when Sakura grabbed his arm.

"Hey, look at those guys."

Sasuke followed her line of sight and saw three teenagers he didn't recognise walking past their training field. The youngest was a boy about their age with red hair, and he was with another boy and a girl, both of whom were two or three years older. They were dressed strangely, which Sasuke assumed was why Sakura had pointed them out. The redheaded boy had a large gourd strapped to his back, and the other boy had markings painted on his face and was carrying what looked like a person wrapped in bandages on his back.

"Look at their hitae-ate," Sakura hissed, just as Sasuke noticed it himself.

They weren't Konoha shinobi. Instead of the leaf symbol, they were wearing the mark of Suna. Sasuke sat up a little straighter and stared at the three strangers more intently. If they noticed his attention, they showed no sign of it. The girl was saying something and pointing ahead, and then she started running, moving across the ground with fluid ease. The two boys exchanged a glance before taking off after her.

Sasuke stood up. "Let's follow them."

"Why?"

"In case they're the enemy."

He heard Sakura protesting behind him, but she still followed when he started moving through the trees, following the path the Sand shinobi had taken.

"Why would enemy shinobi be wandering around Konoha out in the open?" Sakura hissed, a half step behind him.

"Are you willing to take a chance and let them go because they might not be a threat?"

"What are we going to do if they are a threat?"

Sasuke felt his lip curl up in anticipation. "Then we fight them."

They were heading towards the training fields at the very edge of town. There were fewer shinobi out here, which made it easier for Sasuke and Sakura to trail the Sand shinobi without being seen. The three outsiders were sticking to the clearly marked paths between the training areas, but their pursuers cut across some of the empty fields, sticking to the tree line that ran around the edges of most of the training grounds, acting as borders and providing a change of terrain for sparring shinobi.

"I've never been this far out before," Sakura commented. "Where could they be going?"

"I've heard there's a special training ground on the village border," Sasuke replied distractedly.

"What's so special about it?"

"I don't know." Sasuke paused and squinted ahead. "Do those trees look kind of big to you?"

A few minutes later, it became clear what was special about the training ground farthest from the village. The Sand shinobi had stopped in front of a huge wire fence, at least three times the height of a grown man. Beyond it lay a forest unlike anything Sasuke had seen.

The trees were so huge that the ground beneath them was thrust into deep shadow, and the whole place had an untamed air unlike the patches of friendlier trees in the rest of the training grounds. Sasuke wondered if it was fenced off to keep people out or to keep the wilderness in.

"What is that place?" Sakura wondered aloud.

By the fence, the younger boy performed a series of hand seals and a patch of ground beneath the fence caved in, created a small ditch that he then crawled through, his companions following. Sasuke could hear the older boy complaining loudly.

"Gaara, you made the hole too small!"

They disappeared amongst the trees, and Sasuke broke cover to follow them.

"You seriously want to go in there?" Sakura asked. She was eyeing the forest with apprehension.

There was a sign hanging on the fence close to where the earth jutsu had carved a hole. It said in large letters: Training ground 44. No admittance except to maintenance team until further notice. The chains holding the fence together were covered in seals to strengthen them.

Sasuke crouched down and crawled under the fence before Sakura could stop him.

"What are you doing?" she hissed from the other side, eyes wide and worried. "It says we're not allowed in. We'll get in trouble!"

"Don't you want to know what those freaks are doing in here?"

Sasuke stood his ground and waited. Sakura might complain, but she'd follow him, partly because she'd go along with almost anything he suggested, but mostly because, despite her good girl act, Sakura was a rebel at heart. They'd been in a class together since they were six years old; Sasuke knew her well enough by now.

Sure enough, still grumbling under her breath, Sakura crawled through the ditch and stood up inside the fence, glancing nervously over her shoulder.

"Come on."

Sasuke led the way, following the trail left in the dirt.

It wasn't hard to find the Sand shinobi again. They were walking slowly among the giant tree roots and talking without bothering to lower their voices.

"I don't see why they call it the Forest of Death," the girl was saying scornfully. "What's so scary about this dump?"

"I can see why they'd use it for the chuunin exams, though," the older boy said thoughtfully. "It's not exactly easy terrain."

"You better be right about this, Kankuro," the girl said. "Otherwise we're wasting our time on stupid rumours when we could be doing something useful like training."

The redhead, Gaara, suddenly held up his hand to silence them. He turned and flung a kunai towards where Sasuke and Sakura were ducked behind a tree root. "Who's there?"

Sasuke stepped out into their line of sight, aware of Sakura following closely.

"I should be asking who you are," he said, annoyed that they'd been discovered but unwilling to show it. "You're trespassing."

The bluff almost worked. Kankuro and the girl exchanged a nervous glance, but Gaara's stare was unwavering.

"You're genin," he observed. "I doubt you have permission to be here. You're trespassing just as much as we are."

Sasuke let him have that. "What are you doing in our village? You're not Konoha shinobi."

"What do you think we're here for?" the girl asked. She rummaged around in her pocket and withdrew an official looking piece of paper, which she waved at them. "We're going to take the chuunin exams. There's a rumour going around that one of the exams will take place in this cosy little forest, so we thought we'd take a peek."

"Chuunin exams?" Sakura blurted out.

"You don't know?" Kankuro raised an eyebrow at them. "Shit, Temari, did you hear that? They don't even know about it!"

"Well, they're just kids," Temari replied, shrugging it off. "Give them a couple of years to stop wetting themselves – hey!"

She only just dodged Sasuke's shuriken, which thunked into the ground behind her.

"You trying to start something?" she asked, reached for a weapon.

"Stop talking, start fighting."

Temari moved forwards, her hands full of sharp metal, and Sasuke lowered into a defensive crouch.

"Hey, what are you kids doing in here?"

All five genin whirled around to see a woman walking towards them. She was maybe eighteen or nineteen, wearing a chuunin jacket, and had a full grown tiger slung effortlessly over her shoulders.

"This training ground is off limits right now," she continued, coming out into the clearing and giving them all an exasperated look. "Take your sparring somewhere else, we're working in here."

The tiger sniffed and lifted its head from where it had been hanging in defeat by the woman's side. Catching sight of Sakura standing nervously five feet away, it opened its mouth and snarled. Sakura backed away so fast she tripped and fell into a patch of bushes.

"We're sorry, miss," Kankuro said, eyeing the tiger. "We'll be leaving right now."

"Damn straight you will. I'm even gonna walk you out since I'm such a good host."

It was then that Sakura screamed. Sasuke was by her side in an instant, trying to see what was wrong, and then he realised that what he'd taken for pile of twigs beside her was actually a hand, half buried, its fingers reaching up from beneath the ground.

The tiger squirmed and roared, and the woman dumped it on the ground and flicked a barrier seal over it almost absentmindedly.

"Is it a snake?" she asked, coming over without much haste. "The snakes look worse than they really are, don't worry." Then she saw the hand. "Oh, fuck."

The Sand shinobi had also gathered around them.

"Stand back," Gaara said. "I'll unbury it."

He performed another jutsu, and the earth started pushing upwards, slowly revealing the body as it rose to the surface. As its face came into view, Sakura shrieked again and clutched at Sasuke's arm.

The body wasn't fresh anymore, and the stench was so strong it brought tears to Sasuke's eyes, forcing him to cover his mouth and nose. However, the real horror lay in the fact that insects had burrowed into its flesh and were visible now, crawling over the skin and the ragged remains of a shinobi uniform. The eyes had gone completely, and as Sasuke watched, a maggot fled from the light into one of the empty sockets. He turned away and retched.

"Fuck this shit," the chuunin gasped. "This is why we plaster warning signs all over the damn fence." She flared her chakra in three sharp bursts, a distress signal. "Do you see, kids? This forest is not a playground. People die in here."

Sakura had both hands over her mouth, her face drained of colour. "You think something in the forest did this to him – her – this person?"

"This place is full up to the eyeballs with traps and dangerous animals," the chuunin said. "We don't call it the Forest of Death for nothing."

Sakura was still staring at the corpse. "But it looks like he's been stabbed."

Trying not to breathe through his nose, Sasuke turned back to the body. Sakura was right. The ragged cloth of the dead shinobi's shirt was ripped where a blade had pushed through, and although the red of blood didn't show on the black material, Sasuke could see traces of it on the pale flesh beneath. The chuunin picked up a stick and prodded the shirt up, peeling it away from the skin where it had stuck. There in the abdomen was a puckered wound, maybe two inches long, like a sword had been thrust into the body.

"Worst day ever," the chuunin groaned, and sent out the distress flare again.

Sasuke turned away and was sick again onto the grass.

A/N - Tenzou often wonders, with varying degrees of seriousness, why he's friends with Kakashi. Kakashi never wonders why he's friends with Tenzou.