At a training ground in the Uchiha Clan Compound, Naruto was giving a hands-on lesson in some Ninjutsu.
Naruto asked about Sasuke's current chakra affinities and learned that he now had both lightning and fire chakra.
Once he knew Sasuke's chakra affinities, Naruto had a plan. First came those Lightning Release and Fire Style secret scroll skills, followed by something he had wanted to try before but had never had anywhere to practice: Railgun's Railgun. Naruto knew the principle behind it and felt he should be able to recreate it in the world of Naruto.
With an idea in mind, he immediately got to work.
"Uchiha Sasuke, want to learn a really cool Ninjutsu?"
At Naruto's words, Sasuke was immediately, intensely tempted.
"Of course I do. I've been dreaming of it."
"Here."
Hearing Sasuke's affirmative answer, Naruto tossed him a coin. Sasuke caught it, looking puzzled. He couldn't understand what the really cool Ninjutsu Naruto had mentioned had to do with the coin in his hand.
Just as he was about to demand whether Naruto simply didn't want to teach him, he saw Naruto unleash a powerful, incredibly cool Ninjutsu.
All he could see was a blue-gold beam erupting from Naruto, punching straight through a distant target. It even blasted a long gouge into the ground, which was still smoking.
The sight left Sasuke incredibly excited. He could barely imagine how badass he would look if he learned this Ninjutsu. He had already begun imagining himself after mastering it. Looking at the coin in his hand, he imagined reducing mountains to dust with a flick of his fingers, just like Naruto.
"Powerful, so powerful! Naruto, hurry up and teach me! I want to learn this! What's this Ninjutsu called? It's so damn cool!"
As for Naruto, he was excited too. He hadn't expected to unleash the move on his very first attempt, nor had he expected such destructive power. Steadying his still-trembling right hand, Naruto cleared his throat and discreetly tucked that trembling hand behind his back.
"Ahem, Sasuke, as you saw, that Ninjutsu was called Railgun. Well? Pretty cool, right? Want to learn it?"
Sasuke's eyes sparkled.
"Yes, yes!"
"Ahem, come on. Let me explain the principle."
"First, this Ninjutsu is called Railgun. As the name suggests, it has to do with electricity, which means it has to do with lightning release chakra. To be precise, it's a magnetized-projectile traveling-wave cannon. As for the principle, listen closely.
"First, gather lightning release chakra in your hand, then try compressing the chakra into the coin. Remember, you can only add lightning release chakra. If you mix in fire chakra, the coin in your hand might melt outright.
"Once you've successfully coated your hand in lightning release chakra, you can use chakra nature transformation to produce lightning that coils around your hand. As everyone knows, electricity can generate magnetism, and magnetism can also produce electricity. A changing electric field and a changing magnetic field form a single, inseparable field: an electromagnetic field.
"The coin in your hand will have magnetic force imparted to it by this electromagnetic field. In other words, it'll be magnetized. The stronger its magnetization, the greater the magnetic moment it produces. An object with a magnetic moment will be propelled by a force in a nonuniform external magnetic field. That's why the coin flies out.
"So, strengthening the electromagnetic field in your hand-in other words, increasing the quality and intensity of your lightning release chakra-can give the coin greater acceleration, allowing it to reach the speed of sound. On top of that, its small size and small surface area mean less air resistance, so the Railgun you fire will hit very hard. In theory, as long as you apply an infinite amount of chakra, its power can be infinitely great."
Naruto clapped his hands to indicate that he was finished, but when he looked at Sasuke, he felt a little weary.
"Uchiha Sasuke, did you understand?"
Sasuke's pupils were unfocused, his expression blank. His mouth hung open, and he made "ah" sounds for ages without managing a single word.
The sight terrified Naruto. Sasuke, nothing can happen to you! Otherwise, in this state, you'd still drool even after being cured.
He waved his hand in front of Sasuke's eyes.
"Oi~ Wake up, Uchiha Sasuke! Come on, wake up! What's wrong with you?"
Even then, Sasuke didn't react at all. Frightened, Naruto gave him a kick.
"Ah! What happened?"
Sasuke, who had been kicked to the ground, immediately scrambled up. He remembered listening to Naruto explain that super-cool Ninjutsu. For some reason, even though he understood every word separately, putting them together made it sound like utter gibberish. He was supposed to be learning Ninjutsu, yet somehow it felt even more exhausting than sitting through class.
"So, did you understand or not?"
"Huh?"
Sasuke shook his head desperately. This was way too hard.
"What, you're giving up over this little difficulty? Uchiha Sasuke, remember: if you want to shine in public, you have to suffer in private. Get practicing."
Sasuke looked miserable. This Ninjutsu really was cool, but it really was hard to learn.
"What do I do, Naruto? This Ninjutsu is so hard. I can't even understand the explanation."
"Heh, that's exactly how it should be. All right, practice it yourself later. It's time for us to eat."
Almost the instant Naruto finished speaking, Itachi arrived at the training ground.
"Dinner's ready. Come and eat."
Glancing at the miserable-looking Sasuke, Itachi wondered what Naruto had taught him. Why did he look so crushed?
After an enjoyable dinner, Fugaku personally handed Naruto a cup of tea.
Startled, Naruto hurriedly accepted it with both hands. Just how much respect was he being shown, to have Fugaku personally serve him tea?
"Uncle Fugaku, you're giving me far too much honor. I'm just a junior."
Fugaku smiled and waved a hand, thinking that Naruto really was quite a polite child.
Next, Fugaku recounted Danzo's suicide out of fear of punishment to Naruto once again. This time, however, the brothers Itachi and Sasuke were listening too. Whether deliberately or otherwise, Fugaku had already begun grooming the two brothers.
"I think there's a good chance Danzo isn't dead, and the person who died in prison was most likely one of his subordinates. Now Danzo has completely hidden himself in the shadows. As for your Uchiha..."
After hearing Fugaku's analysis, Naruto offered his own views. But he truly hadn't expected Fugaku to ask him what path the Uchiha Clan should take next. Now the pressure was on Naruto.
He felt rather helpless at the thought of a clan head seeking advice from someone who hadn't even graduated from the Ninja Academy, especially on a matter concerning the clan's survival.
One really dared to ask, and the other really dared to answer.
"As for the Uchiha, I think it's better to lie low and build up your strength for now, because that old bastard Hiruzen Sarutobi is definitely going to die."
Finally hearing what he wanted to hear, Fugaku's eyes positively shone.