Disclaimer: I do not own anyone involved in Naruto. I only own this story.

Small note: I just wanted to point out that this story is in the shippuden era. I'm not sure if you caught that by the summary, so I just wanted to let you all know! Please, enjoy the first chapter ^_^

Chapter One: The Letter

"Iruka-sensei~!" The said male turned around, blinking in surprise. His eyes immediately spotted Naruto, who waved eagerly at him with a large smile on his face. Iruka's eyes softened and he smiled at his student. "You're back from your mission!"

"Ah, hai." Iruka said, folding his arms across his chest. "It wasn't exactly time consuming now that I think about it." Iruka paused in thought before he looked at Naruto. He blinked, noticing Naruto was looking at him with a worried expression. "What's wrong, Naruto? Did something happen while I was gone?"

Naruto shook his head no and reached out, pointing to Iruka's leg. "You're injured, sensei." Naruto said.

"Eh?" Iruka said, his eyes widening as he looked down at his leg. He noticed a dark spot staining his right thigh. He reached down and touched it, flinching a little the jolt of pain. "Now...when did this happen?"

"You didn't feel it?!" Naruto exclaimed. Iruka looked up at Naruto before shaking his head no. "Sensei," Naruto's eyes hardened a little. "What kind of a mission were you on?" Iruka's eyes widened a little and he gulped.

"Naruto, I don't think it's your right to ask something like that." A voice chimed in. They both looked up to see Sakura and Sai standing there, with Kakashi behind them. "But from what I can see from his scraps and the injury, it was a mission that ended badly." Sakura continued as she walked towards Iruka.

"Ah, really, I'm fine! It's probably not that serious." Iruka exclaimed, waving his hands in front of him. Sakura chuckled before putting her hands on her hips.

"Iruka-sensei, let me heal you. I bet you wouldn't want to report to Lady Tsunade like that, right?" She said. Iruka blinked before letting out a sigh. He reached up and rubbed the side of his neck.

"Alright, fine." He said. Sakura gestured for him to sit down, and he did was he was told. Iruka watched the girl heal his leg before he looked up at Kakashi, blinking a little as he noticed his friend watching him intently.

"Kakashi?" Iruka said. Kakashi blinked and looked up at him, as if snapping out of a daze. "Are you alright? You looked like you were day-dreaming." Kakashi chuckled and folded his arms across his chest.

"Nah, I was just thinking. Didn't you have others that went on the mission with you, Iruka?" He said. Iruka's eyes widened. "It's just odd that I didn't see them come back with you."

"A-Ah, that..." Iruka's eyebrows furrowed and he looked down. Naruto looked up at Iruka and his eyes narrowed a little.

"Sensei, what happened on your mission?" He asked. Kakashi held up a hand at Naruto and shook his head.

"Iruka, walk with me to Lady Tsunade's. We need to talk about your mission." He said. Iruka nodded softly and stood up, bowing his head at Sakura. He followed Kakashi as the other began walking. Their pace was slow. Kakashi side-glanced Iruka, watching him stare down at the ground as he played with his fingers.

"Iruka." Kakashi said. Iruka bit his lower lip a little at the seriousness in Kakashi's tone. "What mission did she put you on?"

"...Me and two others were sent to investigate an explosion in the Sand Village." Iruka said. Kakashi's eyes widened. "Tsunade thought it was suspicious, so that's why she sent us. I volunteered to go, and she let me - knowing that my knowledge would prove useful. We got there and there was a bad feeling about the place. Gaara approached us and we asked him questions about the explosion. So far, all we had was a simple "miscalculation in a training experiment." A student was reckless with a bomb and accidentally set it off, killing himself and 4 others in the process." Kakashi's eyes narrowed and he rubbed his chin slowly in thought. "Me and the others didn't have anything else, so we were heading back when a group of Sound ninja came out of nowhere and attacked us. They killed the other two men I was with and knocked me out. I don't know how long I was out but when I woke up, I was near the gate of the village. I don't really know what their intent was, but-"

"-Wait, did you say Sound ninja?!" Kakashi exclaimed. Iruka blinked up at him and slowly nodded. Kakashi's eyes narrowed. He grabbed Iruka's hand and began running towards Tsunade's headquarters. Iruka exclaimed, his eyebrows furrowing but followed him.

"K-Kakashi! What's wrong now?!" Iruka said. Kakashi remained silent as he kept running. They busted through the doors, startling the Hokage and Shizune. Tsunade blinked and set the report down.

"Iruka, you're back." She said and looked at Kakashi. "Kakashi? Don't tell me you're looking for another mission!" Kakashi shook his head no and pulled Iruka into the room.

"No, it's not that." He said. Kakashi turned and looked at Iruka. "Tell her. Tell her what you just told me." Iruka furrowed his eyebrows and looked at the Hokage, who blinked at them in confusion.

"Is it the mission?" Shizune said, tilting her head to the side. Iruka nodded slowly. "Iruka, report!"

"The two men you sent with me are dead, m'lady." Iruka said. Tsunade's eyes widened. "We investigated the explosion like you said. But all we found out was that it was an accident. A student was misbehaving and accidentally set off a bomb, killing himself and 4 others. We were on our way back and a group of Sound ninja came out of nowhere and attacked us. The other men were killed, but they spared me. I was knocked unconscious and when I awoke, I was laying on the ground in front of the gate."

"Say, Iruka..." Kakashi said. Iruka turned and looked at him. "I just noticed something. You have something in your pocket."

"Eh?" Iruka said, looking down and fishing his hand in his pocket. He blinked in confusion as he pulled out a folded piece of paper. "Now when did this get here?" Tsunade's eyes narrowed and she held out her hand. Iruka immediately gave it to her and they all watched as she unfolded it. Her eyes scanned the letters on the paper before she gasped.

"W-What is it?" Shizune said. "What does it say, Lady Tsunade?" Tsunade looked up, his eyes narrowing.

"Shizune, get Team 9 ready. Send word to the Village in the Sand - and to Gaara - that we're coming and no one should be around the explosion area so Neji could see what truly happened." She said. Iruka blinked, his eyebrows furrowing in worry. Shizune blinked before she nodded, running out of the room.

"Tsunade..." Kakashi said. "Is it what I think it is?" Tsunade looked at him and nodded. "But why send Team 9?"

"I heard that Neji - with the help of Hinata's uncle - learned a new technique with the Byakugan. He can rewind time with the Byakugan and see what happened, but he can only rewind it to a certain point. Hopefully, we'll be able to get what happened." She explained. Iruka looked back and forth between Kakashi and the Hokage.

"Yah, what's going on?!"He exclaimed. "What do you guys know that I don't?!" Tsunade looked at him and sighed deeply.

"Iruka...it's best that you don't know." She said. Iruka frowned and looked at Kakashi, who was watching with him with a worried gaze. Iruka sighed deeply, rubbing the side of his neck before he nodded silently. "You can go home now, Iruka. You've done enough for today." Iruka nodded and bowed at her before he turned for the door.

"What's going on?" Iruka thought as he reached out for the doorknob. "What is now? Why won't they tell me anything...?" Iruka grabbed the doorknob and suddenly, he froze. His eyes widened as a jolt of pain suddenly ran through him. His heart slammed in his chest and the next thing he heard before everything went black was Kakashi's voice, calling out his name.

"Sakura, you're telling me that you didn't trace a single ounce of the poison in his system?" Tsunade said. Sakura nodded, a frown evident on her face. "Are you positive?"

"Yes, I am!" Sakura slightly shouted. "If I did, I'd send him to the hospital! I wouldn't purposely send him to you knowing he was poisoned! When I healed him, there wasn't ANY traces of poison in his bloodline! And you know I'm good at sensing that..." Shizune looked over at Iruka, who was laying unconscious in the hospital bed.

"This is suspicious." Naruto said, his tone tense. Kakashi stood next to him, his eyes glued on Iruka. "It feels like someone's targeting Iruka-sensei."

"Someone's sending a message." Kakashi said. They all looked up at him. "Yes, you're right Naruto. It seems that someone is targeting Iruka but I also feel like the Hidden Leaf Village is also a target."

"Lady Tsunade," Sai said, taking a step forward. "You must tell us what the letter said." Tsunade looked at the three students before she looked at Kakashi, who nodded. She let out a sigh, momentarily closing her eyes.

"It's a creepy letter but once I saw it, I immediately got tense and all of my thoughts went to him." She said. Naruto's eyes narrowed a little. "The letter said I'm getting my revenge, but that was it. I had this gut feeling it was sent by...It all made sense: the ambush Iruka had from the Sound ninja."

"Sound ninja?" Naruto said, his eyes widening. "The Village of the Sound...where..." Naruto gasped and Tsunade nodded.

"I pulled the puzzle pieces together. The ambush of the Sound ninja, the letter, Iruka's life being spared." She walked towards the bedside of Iruka. "He's coming back for his revenge, not only on Iruka and the Hidden Leaf Village, but on you too, Naruto." Tsunade explained, turning around to face Naruto.

"On me...? Who is this guy?!" Naruto exclaimed. Kakashi put his hand on Naruto's shoulder, giving him a look to calm down and just think. Naruto bit his lip, looking over at Iruka then at Tsunade. "The ambush...the letter...revenge...Iruka..." Naruto's eyes widened as he let out a gasp. "It's Mizuki, isn't it?!"

"That's right." Tsunade nodded. "Before we jump to conclusions and immediately set out for him, we must know if the explosion is tied to the ambush. I think it's mere coincidence that Iruka was on the mission but still, I have a feeling Mizuki knew." He said.

"That's why you sent Team 9." Kakashi said. Sakura blinked and looked up at their sensei.

"Why Team 9? Is it because of the new technique Neji learned?" She asked. Kakashi nodded. "I heard about it from Hinata...She said he tried it out and it seemed to work. Now Hinata is learning it as well."

"Hinata, too, huh?" Naruto said with a soft smile. Sai looked at him with an eyebrow arched. "I heard she's been learning a lot of new techniques." Sakura nodded.

"She wants to become stronger so she can protect you." Sai responded. "It's obvious; her motive." Naruto's eyebrows furrowed as he remembered when Hinata protected him during the fight with Pein. His eyes closed at the memory of watching her nearly dying in front of him, letting out a deep breathe.

"Let me know what Team 9 finds on the explosive." Naruto said, turning to walk towards the door.

"Naruto, what makes you think I'll tell you?" Tsunade said, folding her arms across her chest. Naruto stopped as he opened the door, turning his head. Sakura gasped at the intense look Naruto had on his face.

"I told Mizuki twice now." He said. "If he ever lays a hand on my sensei, I'll kill him." Naruto walked out of the room, shutting the door behind him. Tsunade sighed deeply, shaking her head.

"Lady Tsunade," Shizune said. "Mizuki and Naruto have a huge history together, Iruka getting caught in the middle both times." Tsunade looked at her, arching her eyebrow. "I'm saying that...if the explosion ties together with Mizuki, we should let Team 7 go after him."

"And why should I allow that?!" Tsunade exclaimed.

"Well, Naruto became stronger, as have Sakura and Sai." Shizune continued, looking up at Kakashi as she held Ton Ton in her arms. "I just feel like Naruto and the team should go. Naruto wants to settle things between Mizuki, and knowing him, he'll get angry if you send out a different team."

"Shizune is right." Sai said. "As a team, we know Naruto well. If you don't end up sending us to Mizuki, he'll most likely go out on his own. He's done so before, hasn't he?" Tsunade sighed before waving her hand as she headed for the door.

"Fine, fine. We'll let Team 7 go. Now let's get going already." She said. They all followed her out of the door, except Kakashi. He stood there, staring at Iruka before he walked to the bedside.

"Iruka..." Kakashi said softly. "You can stop pretending now." Iruka sighed softly and opened his eyes, furrowing his eyebrows as he stared up at the ceiling.

"...How could you tell I was awake?" Iruka said, turning his gaze to look at Kakashi.

"You have terrible acting skills. I saw you glance your fist when we started talking about Mizuki." He said.

"If you saw, then why did you let Tsunade tell the truth knowing I was awake? Didn't you not want me to know?" Iruka said, frowning. Kakashi sighed and sat down on the bed.

"I thought you, of all people, should know. You and Mizuki were friends. I didn't think it was right of Tsunade to keep it all a secret." He explained. Iruka sighed and closed his eyes, reaching up to rub the side of his head.

"...I never thought I'd be hearing of him again. It's been so long. Too long. Why now, though?" He said. Kakashi shrugged and looked at Iruka.

"Maybe he's been spending all this time learning new techniques." Kakashi suggested. Iruka's eyes opened and he looked up at him, his eyes slightly widened. "It's possible, Iruka."

"I don't want to think that!" Iruka exclaimed. Kakashi blinked at him. "Do you know how hard it was to bring him down last time?! Plus, those two idiot brothers were a lot of trouble! We both were hurt badly! I don't want to think that he's learning new techniques. It means he's stronger than last time, and I don't mean by that liquid he drank! He'll be harder to defeat-"

"Iruka." Kakashi reached up, holding Iruka's face in his hands. Iruka's eyes widened and a blush crossed his cheeks. Kakashi's expression was serious. "You're not going to tied in the middle this time." Iruka blinked.

"B-But, Kakashi!"

"No buts, Iruka!" Kakashi retorted. "You were injured badly both times! I don't want you injured a third time. I won't let you go on the pursuit mission with me and the kids. You have to stay in the hospital." Iruka frowned, his eyebrows furrowing.

"...Alright. Fine. I will." He said. Kakashi nodded and pulled his hands away, getting to his feet.

"Good." Kakashi said. Iruka sat up in the bed, watching Kakashi head towards the door. He bit his lip and looked down as he gripped on to the sheets. "Iruka," Iruka looked up at him. "I'm telling you stay here because I care for you...I don't know how I'll be if I find out you're injured again...You should have saw me last time." Kakashi turned, watching Iruka's expression change to shock. "I was a wreck." Under the mask, Iruka could see a small smile. His eyebrows furrowed and he watched his friend leave the room.

"...Kakashi..." He said softly. Iruka turned his head and looked out of the window, slowly getting to his feet. He went to the window and stared out, watching Kakashi walk out of the hospital. "I'm sorry. You wouldn't understand...I'm the only one that can do this." Iruka closed the blinds and leaned against the window, closing his eyes before he shot them open. "I'm the only one who can stop Misuki."

to be continued...

author's note: wow what a shitty first chapter...i'll let you know this is my first time attempting a KakaIru fanfic, more over a Naruto themed fanfic. ORZ. I hope you enjoyed ^^; lemme know what you think!