I have been a coward since I was a child.

Dark hallways, dark bathrooms, even my own room where I spent most of my time.

Humans are naturally afraid of the dark, but I couldn't even leave my parents' room until I became a high school student.

Now that I'm an adult, I've ended up working at a mediocre research institute.

The distance from my family home to work was quite far.

I tried to find my own place, but I couldn't save up enough money.

So, I ended up living in the staff lounge of the research institute.

...I haven't told the director yet.

Though I think he might have already noticed.

Pretending to work overtime, I stayed late at the lab until all my fellow researchers had gone home.

Fortunately, the lab late at night wasn't that dark. At least, not the wing I stayed in...

The research institute consists of three wings in total. The wing I stay in is Wing B.

Wing B contains the management office, the staff lounge, and the cafeteria.

Wing C consists entirely of laboratories.

. . . And finally, Wing A. Wing A had been closed off since before I joined the institute.

After I started, a fellow researcher told me that Wing A, like Wing C, consists only of laboratories, but it had been closed for a long time because the current scale of research isn't large enough.

But the reality was different. According to rumors, Wing A was forcibly closed due to excessive research and the harsh abuse of test subjects in the past.

That day, as usual, I was brushing my teeth in the bathroom in front of the staff lounge in Wing B. That's when—I heard a mysterious sound from the hallway.

Tap... tap... tap-tap...

What was that sound? I tilted my head and stepped out into the hallway.

Did a beaker roll off a table?

I followed the direction of the sound. The hallway of Wing B was bright.

At first, I thought the sound was coming from a laboratory, but only the humming of machines echoed inside them.

I walked down the hallway again. Then, I felt I was getting closer to the source. The source of the sound was—

In front of the inner door leading to Wing A.

It was closed and firmly locked. I knew that the key to Wing A was kept in the management office.

I stood in front of the door to Wing A and stared at it for a long time.

Right then—a hand suddenly reached out from behind, pushed the door open, and shoved me inside. I fell into Wing A with a short scream.

In the blink of an eye, I immediately stood up and looked back—

But the door was firmly shut. Everything was pitch black. I fumbled around with my hands, trying to find a way back, but the door wouldn't open.

An endless, massive wave of terror began to gnaw at me from my feet up.

What should I do? Maybe I could just scream tomorrow morning when the other researchers come to work.

The problem was how to get through this night, right now.

I saw an emergency light flickering in the distance. My legs wouldn't move forward out of fear, but sitting here in total darkness was just as terrifying.

Eventually, I take one step, then another, to find an exit.