Oh god, the insanity is genetic.

Part 1

This idea's been bouncing in my head for about a month and I thought it was about time to post it. A part two should be coming soon.

By the way, this takes place pre-canon, a few years before they graduated. Very much not canon-compliant.

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Iruka wasn't sure how he got here, at this very point in time, but god did he regret it. There was a reason people weren't supposed to mess with space and time seals unless they were proficient in the art.

But no. Iruka, a lowly chunin teacher, was in charge of the Academy's unit on seals. AKA, the worst week of Iruka's year, hands down.

His students had been relatively tame that morning, the clan children hushing as soon as he announced the class's topic, no doubt having been told horror stories of seals gone wrong. The civilian-borns were a bit more rowdy, but easier to dishearten than the others.

Naruto, as always, was not in his seat. He burst in two minutes later, greeted by Iruka's unheard berating, and started fiddling with a kunai in the back, obviously not paying attention.

By then, the chunin had just finished explaining the basic sealing radicals and their functions. "Any questions?" As always no one did, a few children looking like Iruka handed the stars to them and the rest staring at him like a madman. He asked Sakura to pass out paper and ink and sat back at his desk, grading papers and keeping a close eye on the class.

They were supposed to copy a simplistic seal he drew on the chalkboard, just the kanji for light. As it would suggest, the seal converted chakra into short flashes. The assignment was to modify it with stabilizers to produce a steady stream. The seal had a number of uses out in the field and was one of the most widely used in Genin Corps, so it was important they learned it first.

Iruka looked up from Choji's homework to see Shikamaru sleeping (he was probably done anyways), Ino arguing with Sakura, Shino, Hinata and Daiki conversing quietly, in contrast to Kiba, Izuru and Choji yammering about the latest samurai movie. Most of them were finished or had gotten help, so Iruka decided to leave them be.

That only left Naruto. Who was... not sleeping for once. Iruka got up from his desk and made his way to Naruto's desk, helping the ones with unfinished seals along the way. He reached Naruto's desk after two near-explosions, which was much better than he expected.

Naruto's handwriting was terrible, everyone knew, so Iruka was mostly worried about that. An unsteady hand in seal-making could be lethal. The blonde looked completely unbothered, picking his nails with a dull kunai, but he lit up as soon as Iruka approached him.

"Iruka-sensei, Iruka-sensei! Look what I made!" he said eagerly, practically bouncing in his seat.

Iruka chuckled. "Alright, let's see what you've got."

He stared at the paper. The paper without a light seal. The paper with an incredibly complex seal that looked like something Jiraiya of the Sannin or Namikaze Minato would come up with.

"What is this."

"You said we had to make a squiggly picture, so I made one, 'ttebayo!"

No. That was not what Iruka said. He pinched the bridge of his nose. "Okay," he sighed after a minute. "I do not get paid enough for this, but okay. We either burn it or turn it over to R&D." Naruto's face fell.

This, understandably, caught the attention of most of the class.

"What happened!?"

"Burn it, burn it, burn it, burn it!"

"Ha! As if the dead-last could've made anything dangerous."

"WE'RE ALL GOING TO DIE!"

And the class devolved into its natural state of an unorganized mess, but what else was new.

But the loudest of all was Naruto, who shouted, "No! It's mine!"

In Iruka's desperation to get that unholy seal out of Naruto's hands where it could destabilize existence itself, Naruto's kunai, which was still in his hands, sliced through his skin. Naruto howled in pain and dropped the seal on his desk, where the blood spilled.

The seal. Where the blood spilled. Shit.

It glowed, and with a poof of pink smoke, Naruto was gone.

Oh Kami, Naruto was gone.

Someone screamed.

That was it. Iruka was dead. He lost Naruto, the village jinchuriki, his unofficial little brother, to a seal.

An unrecognizable voice squawked, "Where am I?"

The smoke cleared, revealing a girl wrapped in a yellow combat kimono, about his class's age, with long crimson hair sitting in the place of Naruto.

She looked around the classroom confusedly, eyes wide and blinking like an owl, but Iruka could see a calculating look in her eyes. A Konoha hitai-ate peeked out from her locks.

Iruka relaxed at the sight of it. She wasn't an enemy.

"Hey!" the girl yelled. "Who are you? Where am I? Wait, is this the Academy? I graduated almost a year ago, 'ttebane!"

With all the patience he could muster, Iruka tried calmly explaining. "My name is Umino Iruka. There was an accident, one of my students spilled blood on an unidentified seal. I think you two switched places."

The girl looked mollified, if not a bit sheepish. "Oh. Sorry 'bout that, 'ttebane. I could take a look at the seal, if you'd like?"

"Feel free, but I doubt you could do much. This goes way beyond my knowledge," Iruka said dejectedly, pointedly ignoring the gossipping of the class. He handed over the seal. "Careful, I don't know what it does. I trust," he sent her a pointed look, "that you will not do anything foolish with this."

"You can count on me!" she saluted, a jaunty grin playing on her lips.

Iruka turned back to the class, all of which were shamelessly gawking, and felt like banging his head on a wall. "Alright class, let's get back to work. I'll send for some specialists to investigate further."

"But Iruka-sensei! Can't we just talk to that girl for the rest of class?" Ino, ever the opportunist, whined. "It's not like we'll get anything done in this state anyways."

Curse children and their thought-out reasoning.

He gave in with a sigh. "Fine." He turned to the girl in the back. "By the way, what did you say your name was?"

She stood up, hands on her hips. Just like Naruto. "I'm Uzumaki Kushina! But you can call me Kushina. I like ramen and seals and I'm going to be Hokage, dattebane!"

Iruka was fairly certain his brain flew out with those words. How would he explain this to the Hokage?

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