Part 1 I have never been a superstitious person. I’m a software engineer; I work with logic, data, and things that can be proven. But there is an experience from five years ago, when I was living in an old apartment complex on the edge of the city, that I still cannot find a rational explanation for.

It was an older building, built in the 90s, with thin walls and terrible soundproofing. I lived in unit 402. The apartment next door, unit 401, was home to a man I had never seen, but whose schedule I had memorized entirely.

We shared a bedroom wall.

Every night, at exactly 11:15 PM, I would hear his front door open, then slam shut—thud. Then came the heavy footsteps into the kitchen. The sound of running water. The whistle of a kettle. And then, around midnight, he would come into the bedroom.

I could hear the bed springs squeak—creak—as he sat down. Sometimes, I heard him cough—a dry, hacking cough like a heavy smoker. Some nights, I heard him on the phone. His voice was low, a mumble; I couldn’t make out the words, but the tone sounded sad, sometimes angry.

At first, I found it annoying. But living alone in a strange city, those sounds gradually became a weird source of comfort. It made me feel like I wasn’t alone.

Once, I was sick and bedridden for three days. That night, I heard him sneeze violently on the other side of the wall. Without thinking, I called out: “Bless you.”

Silence on the other side for about five seconds. Then, I heard three soft knocks on the wall. Knock. Knock. Knock. A silent thank you. I smiled and knocked back three times.

From then on, we had an invisible bond. We never met in the hallway, never crossed paths at the elevator. But I felt like I knew him. I mentally called him “The Neighbor.”

Everything was normal until a night in November. It was raining heavily. Around 2:00 AM, I was woken up by a strange sound from the other side of the wall. It wasn’t the usual footsteps or coughing.

It was crying.

The crying of a grown man, trying to suppress it but failing. It sounded so desolate and desperate that my chest tightened. He was crying and mumbling a name: “Lan… why… Lan…”

The crying lasted for nearly an hour before stopping abruptly.

The next morning, driven by worry, I decided to break the unwritten rule of apartment living. I wanted to go over and check on him. Maybe he needed help. Maybe he had just lost a loved one.

I stepped out of my room, took three steps to the left to stand in front of door 401.

I raised my hand to knock, but my hand froze in mid-air.

The door to 401 didn’t look like my door. It didn’t have a doorknob.

The lock was completely rusted over, fused shut into a reddish-brown lump of metal. But what was more terrifying was the thick iron bar welded across the door, bolted into the doorframe. The layer of dust on the iron bar and the floor in front of the door was thick enough to write in. And there were absolutely no footprints.

No one could have entered or exited this door for at least 10 years.

My heart started pounding, thumping against my ribs. I stepped back, staring at the faded number 401. Maybe he used a different entrance? Maybe a back door? But this was the fourth floor; there was no back door. A window? The window looked straight down onto the asphalt.

I ran down to the building’s security office. The old guard was drinking tea, looking surprised to see me with a face drained of blood.

“Sir,” I gasped. “Unit 401… who lives there?”

The guard frowned, putting down his newspaper. “401? Why do you ask?”

“I… I heard noises. Last night they were crying so loud.”

The guard’s face changed. He stared at me for a long time, then spoke slowly: “You’ve only been here two years, so you don’t know. Room 401 has been sealed for 8 years. Ever since the fire.”

“Fire?”

“Yeah. A guy lived alone. Smoked a lot, fell asleep, and dropped a cigarette on the mattress. Burned the whole bedroom. He suffocated in there. His wife, named Lan, had left him a few months prior… Wait, did you say you heard crying?”

My ears started ringing. His wife’s name was Lan. Last night I heard him clearly calling “Lan.” And the clicking of the lighter—click click—that I heard every night… The dry smoker’s cough…

“Yes… I heard it,” I stammered.

The guard sighed, lowering his voice as if afraid someone would hear: “You’re not the first. The three tenants in 402 before you all moved out early for the same reason. They said… they heard scratching on the wall.”

I felt a cold shiver run down my spine. I had never heard scratching. Just normal living sounds. And the knock answering my blessing.

I went back to my room, packed my bags that very day to crash at a friend’s house. But before leaving, I had to go back into the bedroom one last time to get my phone charger plugged into the outlet right against the shared wall.

The room was deathly silent. Afternoon sun streamed in, illuminating floating dust motes.

I bent down to unplug the charger. And right then, right next to my ear, from the other side of the wall, a raspy voice, crystal clear, spoke up. Not an echo, not a hallucination. It was so close I could feel the vibration in the wall.

Part 2 “Where do you think you’re going?”

The voice didn’t sound like someone speaking through a wall. It sounded like the person was standing right next to me, pressing their lips against my ear, separated only by a thin layer of wallpaper. The sound was dry, like dead leaves being crushed.

I froze. Every muscle in my body locked up. I wanted to run, but my feet felt nailed to the floor.

Silence.

“I asked… where do you think you’re going?”

This time, the voice was louder, accompanied by the sound of fingernails gently scratching against the plaster. Scritch… scritch… That sound made goosebumps erupt all over my body. That was the scratching sound the guard had mentioned.

I didn’t answer. I yanked the charger out of the socket, grabbed my backpack, and bolted out of the room like a madman. I didn’t dare look back. I had the feeling that if I looked back, the wall wouldn’t be a wall anymore.

I ran all the way down the stairs, skipping the elevator, and burst out onto the main street in the blazing afternoon sun, yet my body was as cold as if I had just walked out of a morgue.

I stayed at a friend’s place for a week, then found a new apartment in a different district. I hired movers to clear out the rest of my stuff from the old apartment; I absolutely refused to go back there alone.

I thought it ended there. I tried to forget “The Neighbor” and the burnt room 401. I told myself it was just overwork, auditory hallucinations, or maybe resonance from other floors echoing weirdly.

But the truth always has a way of finding you, in the worst way possible.

A month after I moved out, I received a call from my old landlady. She said she needed to return my deposit and wanted me to come sign the lease termination papers. I agreed to meet her at a coffee shop, unwilling to return to that building.

The landlady was a middle-aged woman with a gaunt face. She handed me the envelope of money, then hesitated for a long time before speaking: “You… when you lived there, did you notice anything strange?”

I intended to deny it, but seeing the worry on her face, I nodded. “I heard someone in the next room. Room 401.”

She sighed, her hands trembling as she held her coffee cup. “I know. Everyone who lives there says that. But last week… last week I called contractors to break down the door of 401 to renovate it. I planned to rent it out again after all these years.”

“And?” I asked, my heart starting to race.

“When they broke down the wall separating your bedroom and room 401… they found a hole.”

“A hole?”

“Yes. An old ventilation shaft, covered by a wardrobe on the 401 side, and wallpapered over on your side. But the strange thing is…” She swallowed hard. “That hole led into a hollow space between the two walls. It was about 60cm wide. Enough for a person to fit inside.”

I felt nauseous. A space between the walls?

She continued, her voice dropping to a whisper: “Inside that wall cavity… they found a filthy old mattress, dozens of water bottles, and cigarette packs. And… a lot of photos.”

“Photos of what?”

“Photos of you.”

I went numb. The world around me seemed to spin.

“Photos of you sleeping. Photos of you sitting at your desk working. Photos taken from behind while you were cooking. All taken through tiny cracks in the ceiling and corners of the wall that you never noticed. And the most terrifying thing is…” She pulled something wrapped in a tissue out of her handbag.

It was an old, beat-up tape recorder.

“The police found this in that hole. They said the batteries died long ago, but there was a tape inside.”

I looked at the recorder, my limbs turning to jelly.

Part 3 The landlady wouldn’t let me listen to the tape. She said the police had kept it as evidence. But she recounted what the officer had told her.

The tape was full of audio recordings of my life. The sound of me snoring. The sound of me talking on the phone with my mom. The sound of me singing absentmindedly in the shower.

And mixed in with that was the voice of a man. He whispered into the recorder, as if having a dialogue with me.

When I was on the phone: “He’s lying… don’t trust him…” When I was eating: “That looks good… I’m so hungry…” And the recording from the night I sneezed.

My voice echoing in: “Bless you.” Silence. Then his whisper, right against the microphone, sounding chilling: “Thank you… my friend… I’ll come out to play with you soon…” Followed by the knocking: Knock. Knock. Knock.

The man wasn’t a ghost. He wasn’t the guy who died in the fire years ago.

The police investigation revealed that after the fire, room 401 was abandoned but not properly sealed. A homeless man with severe schizophrenia had managed to sneak in through the window (he climbed up the external water pipes). He discovered the technical shaft between the two walls—a design flaw of the old building.

He had lived in that crawl space, less than a meter wide, for two years. He lay there, right on the other side of a thin layer of brick, listening to me, learning my habits. The cough I heard was his. The footsteps were him walking around the soot-filled, burnt room. The crying calling for “Lan”… was likely his hallucination, or he was reenacting the story of the previous owner he had heard rumors about.

What haunts me the most isn’t that a mentally unstable stranger was living next to me. It is the detail about that final night.

The police said that, based on the marks left behind, on the night I heard the crying, he had been trying to chip through the wall behind my wardrobe. He had managed to pry off a large chunk of plaster. He was planning to crawl into my room.

If I hadn’t decided to move out the next morning… if I had slept there one more night…

I might have woken up to find him standing right at the head of my bed, watching me sleep, with the smile of someone who had listened to my breathing for 700 nights.

To this day, whenever I move to a new place, the first thing I do isn’t unpack. It’s go around and knock on every single wall. I press my ear against them, listening intently.

Not to check the construction quality. But to make sure that when I say “Hello,” no one inside the wall whispers back.

And sometimes, in my worst nightmares, I still hear that raspy, dry voice echoing right next to my ear: “Where do you think you’re going?”