When Naruto had spoken to Sakura yesterday and learned about her suffering from memories of a genjutsu that he had assumed was fairly harmless, he really didn't know what to think about it. The thought of her suffering angered him, but he had only just reconciled with Sasuke. He didn't want to make an impulsive decision that could become a disaster. Plus, he barely knew anything about genjutsu. He never used it himself and Kurama protected him from all of it. It was a branch of the ninja arts he wasn't at all interested in.

He had already spent a lot of time talking with Sasuke, and he had heard absolutely nothing about him torturing Sakura. He only ever talked about Sakura in the context of their adventures over 3 years ago. He didn't seem to be at all angry or annoyed with her. He even laughed talking about the crazy things she used to do to ingratiate herself with him. It made Naruto smile and made him think that the trio could all be friends again. Then he talked to a devastated Sakura and that suddenly didn't seem very likely anymore.

From Naruto's perspective, Sasuke was legitimately trying to atone for his actions. So if he had seriously wronged Sakura in this way, he would have mentioned it at some point. It also didn't really make sense that Sasuke would want to make her suffer this much. Even when he was still in darkness, he just didn't really care about her. His lack of regard for her was cruel, but it was also a reason why he wouldn't go out of his way to hurt her more than he needed to. So this situation made no sense at all to Naruto. He needed to hear Sasuke's side of the story.

Naruto decided to go to the prison and talk to Sasuke. When he arrived, he checked in with the ANBU guards. One of them escorted him to where his friend was being held behind steel bars. Sasuke raised his head to look at him. He was clad in white pajamas and had several chakra seals applied. He was handcuffed, but they were connected around the front. The guard walked off to give them a modicum of privacy.

"Hey, Dobe. What are you doing back here so soon? I didn't expect you to visit for another few days," greeted Sasuke.

"I heard something troubling. I need to ask you about it," Naruto replied.

"Hn."

"Do you remember before we fought, when you used that genjutsu to put Sakura-chan to sleep?"

"Of course... I wouldn't have done that, but there was no way that she wasn't going to follow us. Plus she would have yelled at me the entire time... What's the problem?"

"Why didn't you use like, a pleasant illusion to put her to sleep?"

The raven shrugged.

"I don't know any. Rather, I haven't configured my Sharingan to use any. I don't know if you know this, but I very rarely use genjutsu, much like you. That jutsu was one of maybe two genjutsu that I would ever consider using in a combat situation, and the other one would only be practical in very specific situations."

"So you're saying, you had no choice but to hurt her?"

The Uchiha raised an eyebrow.

"Unless you were willing to knock her out yourself," He looked at Naruto meaningfully. "Which you obviously weren't... Yes, I had no choice. If I had tried to use physical force to disable her, our fight would have begun on the spot since you'd have tried to protect her. And I may not have even succeeded. It would actually have been more dangerous for her if I had done that, since she could have been caught up in our battle. I still don't understand what the problem is. It was a simple jutsu..."

All of this made sense so far to Naruto, but there was a large disconnect between Sasuke's description of the jutsu and Sakura's. Naruto decided to stop acting casual. He looked at Sasuke seriously and recounted what Sakura had told him about the mental damage she suffered. After he finished explaining, Sasuke narrowed his eyes.

"That's the most ridiculous thing I've ever heard. That jutsu is nothing compared to the jutsu Itachi used on me when I was ten years old... I understand she might not be that strong mentally. But this is simply ridiculous. It doesn't matter how weak-minded she could possibly be... I could cast that jutsu on you every day for a year and you would not have any lasting issues. It simply makes it appear that I've moved inhumanly fast and struck them, usually in center mass, depending on where they're standing. The medium of the Sharingan transmits chakra via eye contact to achieve this goal. It wouldn't mirror the effects of death in any way... She might assume that at first, but the unnatural nature of it would become evident soon enough. It has a very limited scope. It's not realistic at all. Genjutsu that can directly tamper with a person's emotions, or the physical processes of the body, are extremely rare or entirely nonexistent. All it would do is cause pain and possibly fear considering the imagery of being attacked... It's a completely absurd suggestion, Dobe."

Naruto pondered this for a while with his head down. To him, it really didn't seem likely at all that Sakura was lying.

She loved the Teme before this happened. Now she acts like she hates him and resents the fact that I even let him live. Does it even make sense that her change of heart could be manufactured? Naruto wondered.

He raised his head to look at Sasuke again.

No, it really doesn't.

"Teme... She didn't sound like she was lying... At all. She's lied to me before, it was completely different."

Sasuke glared at him impatiently.

"Dobe, this isn't up for debate. There is no way that the jutsu could mirror the effects of death. Even my brother's jutsu, Tsukuyomi, could never do that. Tsukuyomi is only devastating due to the extreme amount of time that you spend inside the jutsu landscape. This is something that is psychologically damaging. Other genjutsu could cause psychological damage in other ways. For instance, presenting illogical or disturbing imagery and involving the target in it... Yuhi Kurenai would be much better to ask about this than me. But I digress..."

He sighed before continuing.

"There's no way my jutsu, or really almost any genjutsu, could affect someone in the way she said it happened... The jutsu can't deal psychological damage. It causes unconsciousness through tricking the nervous system into sending pain signals... This is possible because the way chakra interacts with the nervous system is well understood. The way chakra interacts with higher brain functions is not at all understood. The pain isn't even usually appropriate for the visual component... One of my team members told me that it reminded him of having a headache. A lot of the time, it doesn't even work... I thought it would probably work on Sakura because she isn't a combat ninja, so her pain tolerance would not be high... If it didn't work, it would at least have stunned her for a time so that I could have knocked her out using another method without having to worry about her avoiding it."

The Uchiha raised an eyebrow.

"Didn't you say Sakura was one of the best medical ninjas here?" he asked.

"Yeah, she is..."

"Then she would never think she was dying. Not with her knowledge. Never. She would realize that she was feeling pain and nothing else. No other aspect of her body failing in any way. The lack of coughing up blood, for instance... There is simply no way a medic of any capacity is tricked by that jutsu for more than a second. They might be knocked unconscious by it, but they'd realize it was genjutsu... Sakura would have noticed so many things wrong with the scenario. She's a liar... No other possibility makes any sense at all. I don't know what her motivation could be, but there's no other alternative."

Naruto looked at him grimly.

"Teme, you don't get it, though. She loved you... She really wanted to save you."

"Hn. So what?"

"Well, now she hates you. She's afraid of you and wishes I had killed you. That was why she didn't heal you... It wasn't because of anything else you did... Not that she was okay with everything else... She was just incredibly bitter and upset about the jutsu..."

"Again, the jutsu cannot possibly do what she's saying it did. I can't explain her actions. I just know how the jutsu works. Even a young child would not be traumatized for any meaningful length of time by that jutsu. It's an obvious lie, Dobe."

Both young ninjas were getting tired of the back-and-forth nature of this debate. They started glaring at each other as was common for the two of them.

"But would she really put so much towards an obvious lie, Teme? She avoided me for a long time because she was so uncomfortable about telling me what happened because she knew I wanted to forgive you. What could her motivation possibly be?"

Sasuke's gaze became claustrophobic.

"To manipulate you, perhaps?"

Naruto stared back with the same intensity.

"Manipulate me to do what? It doesn't make any sense, Sasuke."

"What she is saying makes even less sense. Use the simplest explanation. Here, I'll help you. Is the problem that you think I am the one lying about the jutsu?"

"I guess that's possible..."

"Hn. Go to the building I used to live in when we were Genin. Check the bookcase behind the stairs. There should be a large book that is undecorated aside from an Uchiha symbol on the front cover. It's about this big..." Sasuke indicated a space about a foot tall and half as wide. "And it's a light grey color, I believe. Don't try to open it, it has a blood seal on it. Bring it back here and I'll confirm what I'm talking about."

Naruto relaxed quite a bit.

"OK, Teme... I really want to believe you. I don't want to believe that you hurt Sakura-chan so much... It would feel so awful for me to find out I defended you after you had done that to her... She's so important to me..."

Sasuke gave him a rare sympathetic look.

"I know, Dobe. I tried to get her to like you instead, it just didn't work out back then. I thought she was interested after you defeated Gaara, but I never really understood what she was thinking. Anyway, go get that book and come back."

Naruto frowned at him and ran off. He told the guard he'd return in less than a half hour. He then exited the prison and headed towards the Uchiha district.

/

Sakura was sitting in an easy chair in the living room of Ino's parents' house. Ino was standing behind her with her hands on both sides of the pinkette's head. This was the first time Ino was looking into her mind in relation to this subject. Sakura felt a lot of trepidation about letting Ino see her feelings and memories.

"Forehead... This is so weird," Ino commented.

"What is?" Sakura asked, trying to stay still.

"Here, let me show you."

Ino attempted to bring Sakura into her own mindscape. It was a difficult task because Sakura had never done it before. Sakura found herself in a pink landscape, standing next to her childhood friend. Ino smiled gently at her. She motioned towards a glowing door.

"See, this is the gateway to your recent memories... Like those of the past few weeks or so. It shouldn't be glowing... Brightness is representative of meaning, or significance for a person... But this isn't a memory... This is just a gateway. We would have to go through it to actually see your memories from that time," Ino explained.

"Should we go through it now?" asked Sakura.

"Sure... Come with me."

Ino opened the door. They walked through the glowing doorway.

The room inside was an absolute mess. The walls were painted every shade of every color in existence. Twisted furniture, garbage, and debris laid everywhere. Sakura realized that this was actually her room at her home. But nothing except the shape of it was the same. Ino's eyes were like dinner plates.

"So, what does this mean, Ino-pig...? Why is it such a mess?"

"Uh... The organization of the memory room signifies how orderly the mental state of the subject is. An organized room would mean a person with a disciplined and focused mind... Which should be a person like you, Forehead... I don't understand this. I'm sure that's what it means. I study this stuff all the time. It's part of my job..."

Sakura's eyes widened.

"My mind is in chaos...?"

"It looks that way... Here, let's pull up a memory. Think about something significant that happened recently."

All that really occurred to Sakura was the conversation that she had with Naruto. Though she had misgivings about showing something so personal to Ino, there really was nothing else significant other than the tragedy that had started all this, which might not be recent enough. The rest of her life had been completely uneventful as she focused on work to try to distract herself. She started to reminisce about the talk she had with Naruto in the hospital room.

On top of a huge pile of broken kunais in the corner appeared a bowl of ramen which was steaming. The two girls walked over to look at it. The broth was glowing a furious red color and the noodles were bright pink. It looked extremely strange.

"I thought about talking to Naruto yesterday... I guess that's why it's ramen...?"

The two friends leaned over the top of the bowl, staring down into it. It didn't look the least bit appetizing.

"Yeah... It will create an object that you associate the person with. Red signifies a state of intense anger, violence, or bitterness... I've never seen one quite that color. I hope you didn't hurt Naruto..."

Ino gave Sakura a joking smile.

"I didn't... But I wasn't that nice to him, either... What about the pink?"

"Pink is romance, love, or a state of sentimentality or attachment for another person... I guess that makes sense since it involved Naruto... You've always had something going on with him," Ino said playfully.

Sakura glared at Ino.

"Shut up... How do we view the memory?"

"I'll do that part... It's a little complicated."

Ino did a few strange handsigns that weren't used in normal jutsus. A ghostly version of Naruto and Sakura facing each other appeared in the center of the room.

Ino and Sakura were observing the memorable parts of the conversation from yesterday. Sakura blushed at how embarrassing it was to watch yourself get so distraught over something. The blush stayed on her face during the part where they talked about their feelings awkwardly.

"You could have been a bit more romantic, Forehead..." Sakura's eye twitched in response. "Anyway... This memory isn't actually as intense as the colors would indicate. Don't get me wrong, there were some parts where either you or Naruto were clearly quite emotional... But the color would indicate something on the level of crying your heart out for the whole memory... While also feeling a deep sense of romantic love throughout. Your confession to him wasn't very heartfelt... I mean, I'm sure you meant it... But the fact is, these colors are wrong. They're indicating a level of emotional attachment that isn't there," Ino explained.

"What if I'm feeling that way below the surface...?"

Ino looked at her quizzically.

"Were you?"

"I don't know... My mind has been all mixed up. I don't really know what I'm feeling most of the time... I knew I loved Naruto because of how I felt when I saw him in pain... That along with our memories together... Other than that, I have no clue what I'm feeling other than upset, angry, and scared of Sasuke-kun..."

"I'm not sure, Forehead... I'd have to ask my father about this. I'm not even sure he's seen anything like this happen before. Anyway, I'll go back to looking for the memory from the end of the war... You can leave your mindscape whenever you want, just think about the room we're in in the real world..."

Sakura did so. She found herself sitting in Ino's living room with the blonde's hands cradling her head. She took a deep breath and tried to relax as Ino searched through her mind.

/

Naruto had retrieved the book. He was heading back into the prison to show it to Sasuke. The guard nodded to Naruto as he walked towards the Uchiha's cell.

"You got the book, Dobe?" Sasuke asked. Naruto waved the book he was holding. "Good. Let me see."

Naruto passed the large book through the bars. It barely fit. Sasuke held the book in his two hands cuffed together. The raven-haired man bit his thumb and swiped it across the Uchiha logo. The bloodstain disappeared and he opened the book.

Sasuke flipped through the book. He checked the table of contents first. He had a specific chapter in mind. His dark eyes brightened in interest when he looked at the next page.

"This book is called "Sharingan: A Cursed Bloodline." It was written by an Uchiha historian sometime around when your dad was Hokage... It mostly talks about how the Sharingan grew more ubiquitous among the Uchiha over time, the beliefs and superstitions about it, and the attempts from within and outside the Leaf to steal it... It's really interesting. More importantly, there are a few chapters detailing the Sharingan's capabilities... And this is the only source of an actual description of how Sharingan genjutsu works... On paper, anyway. It's a little different from ordinary genjutsu in that it's a bit more limited, but it can be applied very quickly and without hand signs, using eye contact alone. It's the ideal method of using genjutsu for someone who doesn't want to spend a lot of time training in it," Sasuke explained.

"I see," mumbled Naruto, not very interested in this information.

Sasuke had located the correct page. He traced the lines with his finger.

"Here it is. I'll read it to you."

"Genjutsu delivered through the means of a normal Sharingan Eye has no more capabilities than your average genjutsu other than the medium of transference via eye contact. The genjutsu that can be applied consists of deceiving the senses and tricking the brain of the target to send the wrong signals in a very basic way. Only primal feelings like pain and pleasure can be directly stimulated by genjutsu, with very rare exceptions. There is no known way to directly affect the complex emotions of a target. The Sharingan Eye mainly acts via a jutsu which the Uchiha refer to as "Genjutsu: Sharingan." This is not a proper jutsu as there is no incantation nor are there any hand signs. The user activates a Sharingan with at least two tomoes and makes eye contact before..." Sasuke read aloud.

Naruto held up his hand. Sasuke stopped reading and looked at Naruto meaningfully.

"The important part there was a few sentences back, right?"

"There's another part talking about how the genjutsu of the Sharingan works, but yes. That is how I know that Sakura is lying to you. How could she have suffered that much if all I did was cause her some physical pain with a jutsu which would have been gone when she woke up? I'm not making any excuses for what I did, but you need to understand that it's simply not possible, Dobe."

So Sakura-chan had to have lied...? That doesn't make any sense, Naruto thought.

He needed to see it for himself. There had to be some other explanation.

"Can I read it myself? I just want to make sure," Naruto asked, holding out his hand.

Sasuke nodded and passed the book back through the bars.

"It starts on page 221."

Naruto grabbed the book and started to flip to that page. He found the passage that Sasuke had just read aloud and he decided to do the same. This issue was incredibly important to him and he refused to overlook anything.

"Genjutsu delivered through the means of a normal Sharingan Eye has no more capabilities than your average genjutsu other than the medium of transference via eye contact. The genjutsu that can be applied consists of deceiving the senses and tricking the brain of the target to send the wrong signals in a very basic way... Only primal feelings like pain and pleasure can be directly stimulated by genjutsu, with very rare exceptions... There is no known way to directly affect the complex emotions of a target... Seventeen... The Sharingan Eye mainly... Wait, what? Why does it say 17 there?"

Sasuke rolled his eyes.

"That's a citation, idiot. If you flip to the back of the book, there's going to be an appendix where he credits different people for the knowledge he used to write the book."

Naruto did what the raven suggested. He had never heard of citations before and he was somewhat interested in learning about them. He saw a list of entries; each of them were about one paragraph in length. The first one started off like so: "This jutsu was named by Uchiha Kagetaka when he used it on the battlefield for the first time. He later found a wide variety of applications for its use..."

Naruto flipped through a couple of pages of the appendix until he was in the late teens. He scanned for the seventeenth entry. When his eyes found it, he read it silently like he had the first citation. Sasuke's gaze had shifted away from Naruto, bored of his slow reading speed and his meaningless interest in the citations.

17.

My colleague, Uchiha Hideki, disputes this point. He spent a great deal of time studying the brain of a Sharingan user using medical chakra. An interesting fact he discovered was that the neurons related to emotional regulation - the neurons used to activate a Sharingan - are not unique to Uchiha, but exist in all humans. But an even more amazing discovery of his is that the chakra that the human body supplies to these neurons devoted to emotional regulation is extremely similar - if not identical - to the chakra of the Sharingan. A fascinating hypothesis was devised by Hideki at this point. He asserts - with some degree of confidence - that if a subject was in a state of great emotional distress akin to an Uchiha activating the Sharingan for the first time, and then the subject's neurons received chakra from an external Sharingan - likely a genjutsu being cast by an enemy or whoever is trying to confirm the hypothesis - the neurons would misinterpret the injection of chakra from a foreign Sharingan as a release of their existing neurotransmitters (NTs). This is very similar to how the Sharingan when first activated leaves the user in dire straits emotionally due to the sudden dumping of all NTs related to emotional regulation.

This is the origin of the Sharingan being dubbed "The eye that reflects the heart."

But a different result is hypothesized by Hideki. The neurons of the subject would not dump their NTs. They would instead falsely consider themselves empty and start producing more NTs despite the large quantity already present, while the chakra from the foreign Sharingan would simply renew the process with every pulse of chakra sent to apply the genjutsu. This would cause an overload of NTs in the neurons in question within a matter of seconds. This would have the result of inducing a state of extreme sensitivity to strong emotions in the subject. This would be detrimental to the subject's state of mind and their ability to remain rational. This resulting scenario of being governed by powerful feelings could cause loss of free will in the subject, limiting their agency or even pushing them into the role of a viewer stuck inside their own body. Any stimulus provided to the subject would be experienced only in the way that is the most powerful and visceral to them. Due to the subject's emotional state and the way it would cause them to process stimuli, they would engage with any strongly positive or negative experience to such a degree that they would keep it 'fresh' in their mind for a very long time afterwards.

This result is something Hideki predicted based on existing studies. Unfortunately, no civilians showed interest in assisting Hideki with his hypothesis. In addition, it's unlikely that you could ever manufacture sufficient emotional response in a laboratory environment without unethical practices which the Uchiha do not condone.

So with a heavy heart - as our clan's bloodline reflects - I must sadly assume that this hypothesis will always remain a mere hypothesis.

Naruto stared at the page blankly after he finished reading it, slowly absorbing the contents. He didn't know what a lot of the words meant, but he understood the ideas being presented. After several seconds, his eyes turned red. The Kyuubi screamed to spill the blood of the last Uchiha.

He lifted his head to stare at Sasuke bitterly. Sasuke watched with wide eyes.

"What's up, Dobe...?" he asked.

"Teme... I should kill you..." Naruto said in a low growl. He dropped the book.

"Huh...? What do you mean? I know the Uchiha clan did terrible things, but Itachi dealt with them. There's no need to be concerned with it anymo-"

Sasuke was interrupted as a giant Rasengan shredded the bars to the cell. A Naruto clad in red chakra immediately grabbed hold of his former teammate's neck with one hand. He slammed him against the stone wall.

"You fucking bastard... HOW COULD YOU?! She loved you! She would have done anything for you! All she wanted was for you to care about her and see her as someone important! But you didn't care. You made her so sad and miserable when all she wanted was to help you! She's been suffering for a long time now because of your cruel, senseless action on that day... I don't care what you intended anymore! You hurt Sakura-chan... You did permanent damage to Sakura-chan...! I WON'T FORGIVE YOU!"

The blonde was trembling as he spoke, holding Sasuke by the neck. His lack of self-control had the effect of cutting off Sasuke's airflow intermittently. The Uchiha was frantically trying to claw Naruto's hand off of himself, but he had been weakened by the seals placed on him when he was incarcerated. He was shocked and entirely helpless to stop this from happening. The raven was barely getting enough air to stay conscious. He gasped and sputtered.

"You piece of shit Uchiha... I can't believe I protected you from getting killed by the other villages... I protected you while Sakura-chan was crying! While Sakura-chan couldn't sleep because she was scared and hurt! Because you put her through so much fear and pain for no good god damn reason... And I wasn't there to comfort her! She was miserable and alone because I was wasting my time with YOU, you fucking traitor... And then you called her a liar?! I stood here and listened to you call her that after you made her SUFFER?!" screamed the apoplectic Naruto.

Naruto shifted his grip to grab the raven by the collar of his shirt. He began to smash Sasuke against the wall repeatedly, still using one hand.

"After you made her believe that you had ripped her life away from her? Her beautiful life, full of people who love her?!" continued Naruto. He spoke only when he wasn't occupied with trying to hurt his old friend as much as possible.

He let Sasuke fall to the ground after slamming him against the wall one more time.

"And I'm one of them..."

Naruto took a deep, frustrated breath.

"You were able to hurt her BECAUSE she loved you... Because she cared so much about you... That's the worst part... That's the part that pisses me off the most!"

The blonde pressed his foot against Sasuke's chest and stared down at him. The Uchiha's eyelids were fluttering, but he didn't seem to be moving.

"You took her love and treated it like GARBAGE! You treated HER like garbage! Why didn't you find a way to disable her that wouldn't hurt her?! Because you didn't care...? HOW DARE YOU? I should fucking KILL you! I know you don't love her, but I do... So I'll NEVER let you get away with this!"

Naruto picked up Sasuke and threw him against the opposite wall, watching in satisfaction as the Uchiha's beaten and presumably unconscious form crumpled up against it and landed awkwardly. He picked up the stupid book of Uchiha bullshit and flipped through it, finding the offending page and ripping it out. He placed it on top of Sasuke's bloody face.

"Maybe now you can understand how Sakura-chan felt... Being totally at the mercy of someone who you stand no chance against. Who can kill you so easily. Who doesn't care about your life at all. Or how much they're making you suffer and cry. Or how scared and helpless you feel... You stupid asshole..." Naruto spat. He kicked the downed Uchiha in the ribs in hopes of getting rid of some of the bitterness he was feeling. "I thought you were my friend... So what if you didn't love her...? You knew that I did... I don't think I can ever trust you again. I don't care that you're supposed to be good now, because Sakura-chan might never be the same after this. If that happens, I'll really kill you..."

A lot of the fury had left him, but he was still as indignant as ever. It didn't matter if Sasuke could hear him or not; these were things he felt he needed to say. His voice became much calmer as the ribbons of red chakra shrank back inside his body.

"I don't care if I never become Hokage as a result... Anyone who would let someone get away with torturing the woman they love doesn't deserve to be Hokage."

He turned away from Sasuke and walked towards the barred window. He could hear the shouts of frantic ANBU prison guards approaching.

Naruto smashed the window open with another Rasengan and jumped through it, leaving Sasuke behind. Several guards surrounded his battered form as Naruto disappeared into the streets of Konoha.