I didn't think much of it. This was clearly a show of intimidation, a warning. If someone was hiding inside, now was their chance to make themselves known, or else I wouldn't hold back.

No response.

Undeterred, I kicked open the doors of the other stalls.

Something strange happened—someone who should have been there had vanished.

Aside from me, there wasn’t a single soul in the restroom.

Yet, I was certain I had heard someone enter earlier and step into one of the stalls.

The ventilation window in the restroom had long been broken, rusted and immovable. No one could crawl through it even if they wanted to. Besides, why would anyone escape through a restroom window? Beyond it was nothing but a blank wall.

This bizarre incident brought my desk mate’s words echoing back into my mind:

"They say students have disappeared in the old restroom."

The idea of a person vanishing without a trace in a restroom was more baffling than terrifying. I hadn’t misheard or misseen—someone had definitely come in. So how had they disappeared? There was only one exit.

It struck me then: this was almost a classic locked-room mystery.

Deducing and solving such puzzles is a game that fascinates anyone who loves logic.

People with a keen sense of logic often excel in mathematics. To put it bluntly, I was good at math. I enjoyed solving Olympiad problems and reading detective fiction, especially the classic ones.

This was the perfect opportunity to play to my strengths.

I began to survey the restroom stalls, imprinting their positions in my mind. Like Sherlock Holmes or Dupin in *The Murders in the Rue Morgue*, I examined the concrete floor and the walls for any clues. In the second-to-last stall, I found something peculiar written in an obscure corner with ashes:

“Don’t put your hand in the dog’s mouth.”

The writing was scrawled, clearly old, and partially obscured by patches of moss. It was something you’d only notice if you were actively searching.

I squatted down as if using the toilet and lit a cigarette.

The missing person had been wearing cleats—studded soles with traces of grass still stuck to them. Likely a student who had just finished playing soccer.

He had screamed before disappearing.

Judging by the sound, he hadn’t encountered something disgusting but something genuinely startling.

My thoughts paused there.

Suddenly, I realized something: people scream not just from surprise but also from being caught off guard.

I replayed that scream in my head. Yes, it was the latter—utterly unprepared.

I puffed on the cigarette, lowering my gaze. Right where I was squatting, the trail of shoe prints ended, replaced by faint smudges of mud.

He had slipped.

Following this train of thought, I stood, cigarette still in my mouth, and tried to mimic how he might have entered, slipped, and fallen.

His foot would have slid forward, his body tilting backward. Someone falling like that might instinctively reach out to grab something or brace themselves.

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Where was he looking—forward, downward, or upward?

I flicked ash from the cigarette, raising my eyes. Above, shrouded in cobwebs and dust, was a strange pattern in the shadows.

Ah, so that’s what I had been overlooking.

Squinting, I tried to make out the pattern.

Part of it looked like eyes—three pairs of them.

In my mind, the scene unfolded:

The person rushed in, slipped, and fell flat on his back. Lying there, he would have seen the three pairs of eerie eyes above him.

Then he screamed?

No, something crucial was still missing.

His hands.

Where were his hands when he fell?

Three pairs of eyes?

Instinctively, I raised my arm, pointing at the pattern of three pairs of eyes.

Suddenly, a phrase flashed through my mind:

“Don’t put your hand in the dog’s mouth.”

The strange pattern above flared with a crimson glow. The red light pulsed like blood, breaking through the cobwebs, dust, moss, and shadows. The full design revealed itself before my eyes.

It was a wolf—or perhaps a dog—but no real wolf or dog had three pairs of eyes.

The grotesque beast held a cross in its jaws, its six blood-red eyes glaring fiercely at me.

It seemed almost sentient, its curled lips exposing sharp teeth in what looked like a mocking grin.

As if, in the next moment, it would lunge straight at me!

The phrase echoed in my mind: *Don’t put your hand in the dog’s mouth.*

The sinister glow intensified, swallowing my vision and consciousness in a wave of darkness.

When the darkness receded, I wasn’t entirely unconscious.

It felt like I had dreamt for an eternity, though perhaps little time had actually passed.

Upon waking, my mind snapped back into sharp focus, like a clean line on a page, interrupted by a smudged void in the middle.

I found myself still in the restroom.

I was lying on the tiled floor, which was now spotless, polished to a reflective shine.

No ammonia stench, no unsightly stains, no moss.

It was pristine.

The ceiling lights were bright.

This wasn’t the school restroom.

Where was I? I had no idea.

I still remembered everything before I blacked out—the missing student, the cryptic message, the eerie red glow, and the six-eyed beast.

*Don’t put your hand in the dog’s mouth.*

I had reached toward the six-eyed beast, though it felt less like reaching into its mouth and more like being bitten.

It had bitten me. My soul throbbed faintly with pain.

Was the missing student here too?

Standing in this unfamiliar place, I felt no fear, and realizing that surprised me.

My rationality was in control; my emotions cowered in a corner.

Logic is the essence of reason.

But the blank gap caused by my blackout left a dead angle in my logic.

I needed to know where I was.

So I stepped out.

The restroom opened into a corridor, one side lined with numbered doors and the other with glass windows. Outside, the sun shone brightly on a lush green lawn dotted with small trees and a pond. Water cascaded from a mermaid sculpture’s shoulder-held jug. Benches rested in the shade, alongside playground equipment—monkey bars, sand pits, swings, and seesaws.

Tranquil, serene, picturesque—all words that might describe such a scene.

Except for the human corpses scattered everywhere.

Uprooted earth, dried blood, severed limbs, and scattered entrails.

The aftermath of a battlefield, etched with horrifying scars.

The sights and smells were nauseating.

Further out, skeletal buildings exposed their steel frames, thin smoke wafting from their ruins. Shadowy figures flitted across rooftops, like phantoms dancing in a concrete jungle.

Strangely, I felt no fear.

My rationality whispered softly in my ear.

This was an apocalypse. A slaughterhouse of the end times.

The dead roared in the distance.

High brick walls, topped with shards of glass glinting in the sun, encircled the land. The only exit was a five-meter-wide wrought-iron gate, securely shut. A black SUV was parked on the roadside beyond it, its rear hatch open.

Outside the gate, a group of ragged, grotesque figures wandered aimlessly.

No matter how you looked at it, beings with half their heads missing, chests split open, and entrails trailing behind couldn’t possibly be alive.

They weren’t people. They were walking corpses, reanimated dead.

Zombies—the most fitting name.

What an absurd scene. It felt like I was dreaming.

I lit a cigarette.

Aside from the garden and the road beyond the gate, there wasn’t a single living soul in sight.

This was a desolate, abandoned facility.

Silence hung in the air.

The kind that makes your heart race.

Were there others here? I didn’t know.

The zombies outside the gate—they had been lurking here, hadn’t they? Perhaps.

I walked along the corridor, which was on the third floor. The room numbers all began with “3,” and every door was shut. I didn’t open them.

In the middle of the corridor was a staircase, accompanied by a sloped ramp spiraling alongside it. I’d seen such structures in well-equipped public buildings—the ramps were for wheelchairs.

This place felt like an orphanage or a care home.

At the stairwell, there was an emergency fire cabinet. I took off my jacket, wrapped it around my elbow, and shattered the glass to retrieve a fire axe.

Above me, a dog’s barking echoed from the upper floors.