Tech Hero in Another World

By itself, the gate groaned, sliding slowly to the side. The screech of rusted hinges tore through the night air, making Yuuki's skin crawl. She instinctively backed away a few steps, her face pale as paper.

Sui, still clinging behind her, let out a small shriek and grabbed the hem of her hoodie. "Onee-chan!"

Yuuki turned to her, forcing an awkward smile even as her heartbeat thundered wildly. "Hahaha… looks like… we're being welcomed?"

The smile reassured no one—not even herself. But Yuuki knew if she showed fear, the little girl behind her might panic completely. So she drew a deep breath, mustering what courage she had left, and gave a firm nod. "Let's go in. We've come this far already."

Sui gripped her hand tightly, and together they stepped through the gate, now wide open as though inviting them inside.

The mansion's front grounds stretched vast—at least a hectare across. Wild grass had overtaken the cracked stone path, and ancient trees grew unchecked, their tangled branches reaching out like giant hands trying to snatch trespassers.

At the center stood a fountain. The cupid statue perched above it was coated in moss, one wing snapped clean off, and its stone eyes stared blankly into the void. The basin below was long dry, a dark hollow now filled with rotting leaves.

Yuuki swallowed hard, but her feet refused to stop. Her body screamed to turn back, every step heavier than the last. Yet deep inside, her heart screamed louder: don't stop. Because beyond this fear, there was hope—hope of a clue that might lead to Kiriya, the brother she'd lost.

With trembling hands, Yuuki reached for the mansion's wooden doors. Strangely, despite their decades of age, they looked sturdy—far too well-kept compared to everything else around them.

Slowly, she pushed.

Click.

The door swung open with ease.

"Huh? I thought it would be locked…" Yuuki muttered, stunned.

She glanced at Sui, whose face was already drained of color, and forced a small smile. "Come on. Don't stray from me."

Together, they stepped into the main hall. A musty stench of dust and mildew hit them instantly, mingling with a bone-deep chill. A faded red carpet stretched across the floor, stained with dark blotches that defied recognition. Towering bookshelves lined the walls, while a massive chandelier above swayed faintly—despite the absence of wind.

Then—BANG!

The door slammed shut behind them.

"Wha—?!" Yuuki spun, rushing back to yank at the handle, but it wouldn't budge. Locked tight.

"Waaah!" Sui cried, nearly in tears, hiding behind her again.

Yuuki clenched her teeth, fighting to steady herself. "Stay calm… let's just stay calm…"

Suddenly, a strange sound echoed through the hall. Ding!—like an elevator chime.

Both girls snapped their heads toward it. One of the bookshelves was sliding aside on its own, revealing a steel door marked with an old emblem above it.

Yuuki froze. "That's… an elevator?"

Sui pointed with a trembling finger. "Onee-chan! Look… the door's opening by itself!"

Cautiously, Yuuki approached. The elevator looked entirely out of place: new, clean, its metallic walls gleaming as though installed recently. Beside the door was a digital panel, no buttons in sight. Instead, glowing Japanese text read:

「Please scan QR-code」

Yuuki's brows furrowed. "What the hell is this…"

Before she could process it, Sui's phone buzzed violently in her hands. The screen lit up, displaying a new message—an image of a black-and-white QR code.

"O-Onee-chan!" Sui cried, holding it up in panic.

Yuuki's eyes widened. "No way… So that's what it meant…"

Her hand trembling, she guided Sui's phone toward the panel. A small camera beneath it beeped, and a green light blinked.

Ding.

The elevator doors slid shut before their eyes.

Yuuki and Sui locked gazes, their hearts hammering in sync.

"Are you ready?" Yuuki whispered, her voice unsteady.

Sui swallowed hard, then gave a small nod. "…Yes."

A faint vibration stirred beneath their feet.

The elevator moved—not upward, but downward. Descending, deep into the bowels of the earth.

On the digital display, no numbers appeared. Just a single word, flashing over and over again:

「WELCOME」

Yuuki felt the hair on the back of her neck rise. Her breaths came short and ragged, even though the elevator beneath them only trembled softly as it descended. It was as if the air itself grew heavier the deeper they went underground, pressing down on her chest. She knew—whatever waited below was anything but ordinary.

Ding.

The doors slid open slowly, releasing a wave of cold air so dense it felt like thin fog. Yuuki and Sui stepped out cautiously, only to freeze in place.

What stretched before them was no longer the classic interior of a crumbling mansion, but a long metallic corridor gleaming under bluish-white lights. It looked like something out of a spaceship movie. The lights along the walls pulsed faintly, casting an icy glow that emphasized just how alien this place was.

Sui pressed herself against Yuuki, her wide eyes darting about as her face paled. "O-Onee-chan… are we… underground?"

Yuuki swallowed hard. Her voice shook, but she tried to sound steady. "Yeah… it looks that way. Some kind of secret facility, maybe."

Their footsteps echoed against the metal flooring, each step repeating endlessly, as though unseen eyes followed their every move. The walls were lined with futuristic panels, some blinking with strange digital symbols they couldn't understand.

Finally, they reached a massive oval-shaped door, its surface etched with glowing circular patterns. It looked far more advanced than the elevator they had just left.

As before, the digital panel beside it lit up:

「Please scan QR-code」

Yuuki exhaled in relief. "Same as before. Try again, Sui."

With trembling hands, Sui raised her phone. The door glowed green as the code was scanned, but immediately, new text appeared:

「Second access required」

Yuuki frowned. "What? Twice?"

She pulled out her own phone, and as if the system already anticipated it, a fresh QR code appeared on her screen. She scanned it.

Beep.

The panel flashed green once again. But then, another line of text scrolled across:

「Third access required」

Yuuki froze. "What the hell is this…"

Sui looked up at her with panic. "What does it mean, Onee-chan?"

Yuuki gritted her teeth. "This door… it wants three entries. But there are only two of us… so who's the third?"

Silence. The corridor seemed to grow heavier, the blue glow along the walls dimming, wrapping them in a suffocating tension.

Then, a voice rang out from the far end of the hall. A woman's voice—calm, steady, yet carrying a quiet weight.

"Maybe that's me."

Yuuki and Sui whipped around, their bodies stiff with shock. From the shadows, a woman emerged, walking with an unhurried gait. She wore a black biker jacket half-zipped, her long hair tied into a ponytail. Her face was striking yet sharp, the look of someone hardened by life on the streets.

Yuuki instinctively stepped forward, throwing out her arm to shield Sui. "W-Who are you?!"

The woman stopped, raising her hands partway to show she meant no harm. A faint smile tugged at her lips as her eyes studied Yuuki with quiet curiosity. "Me? Before that, I want to know first… what are two kids like you doing here?"

The air froze. Somewhere deep in the facility, the low hum of machines echoed faintly, as if the earth itself was alive.

Yuuki's throat tightened. "W-we… I don't even know how to explain…"

Sui pressed tightly against her back, close to tears.

The woman watched them for a moment before nodding slightly. "Let me guess… you both got the message too, didn't you?"

Yuuki's eyes widened. "What!"

The woman's smile spread. "Hah, so it's true. I got it as well. That message… it led me here. At first I thought it was some scam, but… clearly, it's not."

Without waiting for a reply, she strode casually toward the panel. Yuuki tensed, ready to block her path, but the woman's demeanor carried no hostility. She simply pulled out her phone. A QR code flickered onto her screen.

Beep.

The panel glowed green.

「Third access confirmed. Door opening.」

A mechanical voice reverberated through the corridor as the oval door split apart, sliding to the sides. Beyond it, light poured out.

Yuuki's guard didn't lower. "Wait! Before we go in… who are you really?"

The woman turned, her expression calm, her smile faint. "The name's Kaori." She slid her phone back into her jacket pocket. "Just an out-of-work adult… who happens to be curious about strange things."

Her faint smile lingered, but Yuuki sensed something behind her gaze—something unreadable.

"And besides," Kaori murmured, pulling a baton stick from inside her jacket, "kids like you should stay behind the adults."

Yuuki tensed again, but Kaori's stance carried no malice. If anything, her tone was protective, though she masked it beneath a casual air. At last, Yuuki let out a short breath, signaling Sui not to panic.

Together, the three of them stepped past the futuristic doorway. A short passage led them into a room plunged in darkness. But the moment the door shut behind them, neon strips along the walls hissed to life one by one, bathing the chamber in cold light.

The sight left Yuuki and Sui speechless.

Spread before them was a laboratory fused with a futuristic workshop. A long metal table cluttered with bizarre tools and half-finished machines, small robots abandoned mid-construction, and rows of transparent tubes filled with shimmering blue liquid. Several holographic screens floated in the air, scrolling endlessly with alien code.

"What… what is this place?" Yuuki whispered, barely believing her eyes.

Kaori kept her guard up as she walked slowly, scanning every corner. But her steps stopped when she spotted a massive monitor mounted on the far wall. The screen flickered dimly, a loading bar crawling forward as if rebooting some buried system.

The three of them stood still, watching.

Then, at last, a mechanical voice boomed through the lab in crisp Japanese:

[Welcome to Techno's private headquarters.]

Yuuki and Sui gasped aloud. Kaori narrowed her eyes.

From the screen, the voice carried a name—strange to them, but heavy with hidden weight:

Ultro.