The sky was still a pale blue when Sigma's jetpack finally stabilized, and Kaito gasped for breath above the clouds. The high-altitude wind blew his hair into chaos, while trails of smoke still drifted from the jetpack's engines.
❝Why do I even do this to myself…❞ he muttered wearily, looking down to see the clouds rolling like waves beneath his feet.
A few birds flew past, flapping lazily as if mocking him. But that wasn't what caught his attention — far ahead, several oval-shaped silver drones were hovering in formation.
❝Huh… why are there drones up here?❞ he thought.
His eyes narrowed when he noticed a massive shadow drifting behind a thin layer of mist.
A gigantic airship — metallic brown, about the length of a football field — floated steadily in the sky. Its hull was plated with reinforced steel, and a huge logo was emblazoned on the side: AETHERTECH ACADEMY.
Kaito smiled faintly.
❝So that's Aethertech Academy…❞ he murmured.
But his smile quickly faded.
❝…But how the hell am I supposed to land?❞
The jetpack suddenly shuddered.
The red indicator light on his shoulder began to flash.
"Oh, don't tell me—"
And of course.
The jetpack shot forward like a deranged missile. Kaito tried to unbuckle the harness, but the system had locked automatically.
"SIGMAAAA!!! WHAT DID YOU DO TO THIS MACHINE!?" he shouted into the wind, tumbling through the air like a projectile.
The wind slapped his face hard. He barely avoided a cluster of drones — one nearly clipped his head. A few hundred meters ahead, a student stood on a metallic platform, holding a glowing blue staff. The tip of the staff pulsed with light, and with a flick of her wrist, the air around the field seemed to freeze.
"Don't tell me she's—!" Kaito didn't get to finish.
BAM!
The jetpack dived and crashed hard in front of the student, the impact rattling the entire floor. Kaito barely managed to hang on to his harness.
The student stared at him blankly, then smiled.
"One successful landing, perfectly executed."
She twirled her glowing staff and tapped the floor three times.
"Welcome to Aethertech Academy, Flying Teacher."
Kaito blinked, still half in disbelief that he was alive.
"…You call that a successful landing?!" he snapped sarcastically.
The student only smiled faintly, turned, and walked away without another word — leaving Kaito with the smoking jetpack.
"Well… at least I'm alive."
He finally freed himself from the straps and leaned the jetpack against a wall made of lightweight steel.
Dusting off his clothes, he sighed deeply.
"Alright then… Aethertech Academy. Let's see what secrets you're hiding up here in the sky."
He stepped toward a large metal door on the side of the deck. A light above the door flickered on automatically as he approached, and a soft robotic female voice spoke:
"Welcome, Major Kaito. The main reception hall is located in the eastern corridor. Please be cautious of microgravity zones."
Kaito groaned quietly, scratching his head.
"Microgravity? Sigma, you really could've mentioned that earlier."
The door slid open slowly, revealing a long corridor glowing with pale blue light. Rows of holographic screens displayed streams of advanced tech data.
And with steady steps, Kaito entered the heart of the academy in the sky.
---
Kaito's footsteps echoed softly through the metallic hallway. The faint hiss of gravity regulators hummed behind the walls. The corridor's blue light strips shimmered along with his movement — like living sensors tracing his path.
He glanced a few times at the holographic map displays along the wall, but mostly he just sighed at how mechanical everything felt.
❝A school in the sky, yet it still feels like a war base,❞ he muttered flatly, adjusting his tie.
When he stepped out of the corridor, his eyes widened slightly at the sight of an enormous open hangar.
Dozens of Aethertech students were busy: some carrying energy tubes, others repairing drones, and a few testing gravity fields while floating a few meters above the floor.
The clang of welding, the rattle of trolleys, and the scent of heated metal filled the air.
Kaito walked slowly among them, scanning the area, when—
TAP!
Someone tapped his shoulder.
He turned sharply — and his eyes widened.
"Harusa?" he said, half surprised.
The girl in a yellow-and-purple jacket grinned widely, her cap tilted slightly to the right as usual.
"Yo, Teacher! Long time no see."
Kaito frowned slightly, cautious.
"What are you doing here? This is another school's territory."
Harusa casually patted her jacket pocket and pulled out a half-melted combat wristwatch.
"Relax. I'm just here to get my battle watch serviced. They said only Aethertech techies can fix this Karlon-type model."
Kaito glanced at the broken watch, then exhaled softly.
"Alright… but while I'm here, I need to ask you something."
His tone grew more serious.
"Is there anyone at this academy who can analyze or decrypt data from a mysterious chip?"
Harusa thought for a moment, her expression turning serious.
"A mysterious chip? Hmmm…" she looked up, thinking.
A few seconds later, her eyes lit up.
"Ah! Yeah, there is! His name's Rio — the half-genius, half-crazy kid from Aethertech."
Kaito gave her a blank stare.
"Half crazy?"
Harusa chuckled and lightly punched his arm.
"Yup. But don't worry, he's harmless… as long as you don't give him mint candy."
Kaito closed his eyes briefly.
"Okay. I won't ask."
"Good," she replied with a sly smile.
Then she gestured toward the spiral staircase at the edge of the hangar.
"Come on, I'll take you to his lab. He usually hangs out in Lab 3-B upstairs. It's basically a tech cave — smells like cables, full of coffee, and sometimes there are random sparks flying around."
Kaito followed without a word. Their footsteps clanged softly on the metal stairs. Below, the Aethertech students kept working on their gadgets. From above, the entire academy looked like a fusion of a warship and a living laboratory.
As they reached the door marked "3-B – AETHERTECH RESEARCH UNIT," Harusa turned to Kaito with a teasing grin.
"Teacher, brace yourself. Rio usually pulls all-nighters, so he talks like a broken robot."
Kaito exhaled.
"I've faced mad soldiers on the battlefield, Harusa. I'm sure I can handle one sleep-deprived scientist."
The automatic door slid open, and the sound of humming machines and the rich smell of black coffee filled the air.
"Welcome to the lair of Aethertech's resident genius," whispered Harusa as they stepped in.
Blue monitor lights flickered across piles of strange devices, metal shards, and scattered robot parts.
In the center, a silver-haired boy was soldering a massive metallic shield — one bearing the Primanoel insignia.
"Heh, one more screw and… perfect!"
The voice came from Rio. His sharp eyes gleamed behind cracked safety glasses. He pressed a button on his desk, and the shield pulsed briefly — its energy defense system activating.
When he turned around, his gaze met Kaito and Harusa, who had just entered.
"Oh? Visitors? Don't tell me you're from the Tech Council,"
"Or maybe the Oversight Division?" he added with a faint grin.
Harusa snorted.
"Not even close. I just brought this teacher here to see you, Rio."
"Ah, I see." Rio removed his glasses, stood up, and offered his hand to Kaito.
"Name's Rio. Data systems, defense tech, and occasional troublemaker when I get bored."
Kaito shook his hand firmly.
"Kaito. Flying Teacher — maybe you've heard of me."
Rio raised an eyebrow.
"Ohhh, the Flying Teacher. The one who visited four schools just because of trouble?"
"That rumor's exaggerated," Kaito said flatly.
Harusa chuckled behind him.
"Not really."
Rio laughed, then pointed to the chip in Kaito's hand.
"So, what can I do for you, Teach?"
Kaito placed the mysterious chip on the worktable.
"I need to know its origin and data contents. I found it at Marry Academy, but it might have come from outside the city."
Rio rolled the chip between his fingers, studying it with interest.
"Hmm… the metal texture's different. Chips made in Akarius usually have blue fiber patterns on the back. But this one—" he leaned closer "—is completely black. This design only comes from western nations."
"So it's from outside the city?" Kaito asked quietly.
"Most likely," Rio replied.
He plugged the chip into his console, and a holographic screen flared to life, lines of code cascading down.
"Let's see what you've got…" he muttered.
Moments later, a single file appeared — suspiciously named:
OO-34
"Just one file?" Harusa stepped closer, peering at the screen.
"What's in it?"
"No idea," said Rio, typing rapidly. "But the format's weird… looks like a military encryption type."
He pressed Open—
And suddenly, a loud click echoed.
Rio's eyes darted up.
The chip's connector had been yanked out from behind the CPU.
Someone stood at the far end of the table, holding the chip in her hand.
"Thanks for fixing it for me," came a cold voice.
Kaito, Harusa, and Rio turned sharply.
A girl clad in gray-black armor stood there, bearing a shield marked with the Primanoel insignia — Aru.
"Aru…?" Harusa whispered, stunned.
Kaito stepped forward.
"Hand over the chip. Now."
Aru shook her head slowly.
"Can't do that. This chip belongs to Primanoel. It was lost during a patrol at Marry Academy. And since none of you are from Primanoel, you have no right to access it."
Kaito's tone stayed calm, but his eyes sharpened.
"We weren't stealing it. I just needed to know why it had an active tracker."
"Your reason isn't enough, Teacher," Aru replied coldly.
Suddenly, Harusa raised her Karl-9A pistol, aiming the laser straight at Aru's head — the red beam casting a line across the wall.
"Give it back now, or you'll be out cold right here, Primanoel."
Aru exhaled softly, unimpressed. She reached for the large shield on Rio's table — the same one Rio had just repaired. With a swift motion, she raised it and activated its golden energy barrier.
"If you want this chip," she said in a calm but sharp tone,
"we'll settle it another way."
Harusa lowered her weapon slightly, eyes narrowing.
"What do you mean?"
"Duel." Aru pointed the edge of her shield at Harusa.
"If you win, your teacher can take the chip. But if I win— I take it back to Primanoel."
Harusa glanced at Kaito and smirked.
"Heh, sounds fun. Been a while since I've had a proper duel."
"Fine," Aru replied, then turned to Rio. "Use the battle arena on the fourth floor. At least that room has sound dampeners and structural shields."
Rio shrugged.
"As long as you don't wreck my lab, whatever."
And just like that, the four of them walked out of the lab — their footsteps echoing through the metallic corridor leading upward.
The soft hum of ventilation filled the air, marking the beginning of a confrontation that even Aethertech's own students couldn't have anticipated that day.