The Trembling of Pohrai Academy!

Kazuma Shinga
Illustrations: Hiroaki Nakamura

Pohrai Academy is a massive, fully residential private high school situated at the center of Utsuhama Island—an isolated South Pacific island floating 1,800 km south of Tokyo. With over 200,000 students and nearly 300,000 people including staff and faculty, life within this institution is overwhelmingly abundant. Under the banner of autonomy and self-reliance, countless clubs, hobby groups, committees, unofficial organizations, and even illegal factions secretly operate, enabling students to enjoy a uniquely eccentric school life—this legendary series, originally launched as a play-by-mail (PBM) experience and later expanded across various media, now returns. Set in Pohrai Academy during the 2020s, an unexpected new student stirs up fresh chaos.

Episode 04 The protagonist, who apparently has no idea how they’ll save—or otherwise manage—the school, enters the old library! (Part 6)

We quickly left the balcony with our mouths wide open in shock. Kyota-kun was peacefully asleep nestled against Ame-senpai’s chest, sucking his thumb—so blissfully happy that I almost punched him, but I restrained myself (or perhaps, for someone from the Horror Research Club, seeing those endless bookshelf cliffs would have been more satisfying?).

After walking a short distance, we found a route leading down to the fourth basement level. When Ap-chan sniffed at the corridor wall, a section of it silently slid inward with a soft pokon sound. Beyond lay a narrow spiral staircase—remarkably consistent in design throughout, as if the background artist’s budget had finally run out.

Fourth basement—the destination we’d been seeking!

“Oh, so this is where it leads!”
“Goodness me… what’s going on here?”
“What in the world?”

To our astonishment, none of us (at least those with consciousness and speech) were particularly surprised—we were actually amazed at how little we were shocked.
The scene before us was remarkably ordinary.

It looked just like a regular library—really. The ceiling stood barely two meters high. Neat rows of bookshelves lined the walls. Soft indirect lighting cast gentle shadows. There was no strange odor, and no swarm of pink bookmark ribbons creeping toward us.

A normal-looking library inside the old library?
What an utterly meta shock.

“…So, where exactly should we put these four books?”

Zion-sama calmly asked Ame-senpai.

“Eh… well…”

As Ame-senpai scrolled through her smartphone while glancing around, I realized we were in a circular hall-like space, with bookshelves radiating outward from the center like spokes on a wheel—twelve rows of shelves and twelve aisles.

And then—

From one of those aisles, something large—but small compared to the earlier infinite atrium, more like a grain of rice—appeared soundlessly.

I can’t even describe it properly.
But I’ll try anyway.

First, it hovered in midair—right at the center of the aisle, about two meters above the floor, completely silent.
Its color was primarily purple, with streaks of blue-green, dull red, gray lines or stripes, and scattered black spots here and there. It looked both like a deliberate design and pure chaos; it seemed to have intention yet lacked any clear orientation—just how exactly should one view this thing? This is precisely what “indescribable” means.

Most importantly—it was polyhedral.
It resembled a giant die, the kind professionals call D12 or D20.
The object measured roughly three meters in height, width, and depth, floating freely—no strings holding it up, no magnets repelling it. Rather, it simply… hovered naturally, effortlessly.

We could do nothing but gape upward at it, mouths agape.

“Is that a regular icosahedron? Or wait… a dodecahedron?” Zion-sama murmured. “Wait—no, actually…”

I stared intently.
Each face of this apparent regular dodecahedron bore symbols I’d never seen before. The number of marks varied per face—genuinely like a die.

“Um… instructions, instructions… ah! Here it is,” Ame-senpai tapped her phone. “‘Insert the four books into the fourth face of the polyhedron on the fourth basement level. After that… just go without hesitation—you’ll know what to do! DAAAAHHH!’ Why does it say ‘DAAAAHHH’ like that?”

Ame-senpai sighed, then cautiously circled around to the left, craning her neck—no surprise she wasn’t eager to get too close to this object floating in defiance of all known physical laws.

“Um… fourth face, fourth face…”

Ap-chan and I moved right.
Zion-sama boldly leaned down to peer directly beneath it.

“Eight, nine… wait—this symbol was just here!”
“Twelve, eleven… because it’s rotating, it’s hard to tell!”

Yes—the massive polyhedron slowly turned clockwise, just like a planet spinning on its axis.
Wait—now it began turning around another axis, vertically!
Then suddenly it tilted diagonally counterclockwise? Now it was even more impossible to keep track!

“If this is five… then the other side must be four… wait—that’s wrong—it should’ve been thirteen!”

At my voice, Zion-sama and Ame-senpai both looked up.

“Hmm?”
“What?”

That’s right.
Exactly at that moment—our movements stopped. We ceased speaking. Ceased thinking.

—A regular tridecahedron.
The concept of a regular polyhedron—the kind where all faces are congruent polygons, also known as Platonic solids—flashed through my mind like an encyclopedia entry… then vanished instantly. Had I somehow gained the ability to hear Wi-Fi signals, like Kyota-kun?

But.
But but—but.
A regular tridecahedron.
An impossible shape in this universe.
And space itself flipped upside down.

That’s the only explanation.
I felt it—the world flipping over, folding and warping slowly, turning inside out. Then time began to darken. A blinding darkness surged from far away, threatening to swallow everything whole.

“Run!”

It was instinctive—pure animal reflex.
Ame-senpai dashed into the back of the corridor, cradling Kyota-kun protectively in her arms.
Zion-sama bolted to the right with graceful speed. I desperately followed behind her.
Space flipped.
Which way? Where’s the exit?
Time flickered.

Where’s the exit—?

※

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※Next installment scheduled for November 15th.

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