Chapter 1

I have lived in apartment 6B for four years.

It is not a large place. One bedroom, one bathroom, a narrow kitchen, and a living room with windows that look out over the back alley. I know every crack in the paint, every sound the pipes make at night, every place where the floorboards complain when you step on them.

That is why I noticed the door immediately.

It was in the hallway between my bedroom and the bathroom, where there had always been a blank wall.

A white wooden door.

Plain. Old. Perfectly ordinary.

Except it had not been there the night before.

At first, I thought I was still dreaming. I stood in the hallway in my T-shirt and sweatpants, holding a mug of coffee I could not remember pouring, staring at the brass doorknob.

There was no frame damage. No dust. No smell of fresh paint. It looked like it had always belonged there.

I touched the wall around it.

Solid.

I touched the door.

Cold.

Not cool like wood in the morning, but cold like something kept underground.

I called my landlord.

“Very funny,” he said.

“I’m not joking.”

There was a pause.

“What kind of door?”

“What do you mean, what kind of door? A normal door.”

Another pause.

“Don’t open it.”

I almost laughed.

But his voice stopped me.

He did not sound annoyed.

He sounded afraid.

“Mr. Keller,” I said slowly, “why would there be a door in my hallway?”

“I’ll come over,” he said. “Do not open it. Do not touch it again.”

Then he hung up.

I stood there for a long time, looking at the door.

The apartment was silent.

Too silent.

Usually, I could hear traffic from the street, my neighbor’s TV, the old radiator clicking. But in that moment, everything had gone quiet, as if the whole building were holding its breath.

Then someone knocked from the other side.

Three slow knocks.

I dropped my coffee.

It shattered on the floor, hot liquid spreading around my bare feet.

The knocks came again.

Three times.

Not loud. Not desperate.

Polite.

Like someone waiting to be invited in.

I backed away into the living room and grabbed the heaviest thing I could find: a cast iron pan from the kitchen. Then I waited.

Nothing happened.

Five minutes passed.

Ten.

The door stood there, white and still.

At 9:17, my landlord arrived.

He was usually a cheerful man. Round face, red cheeks, always smelling faintly of cigarette smoke and peppermint gum. That morning, he looked twenty years older.

He pushed past me without saying hello and stopped in the hallway.

When he saw the door, all the color left his face.

“No,” he whispered.

“You know what this is?”

He did not answer.

He reached into his coat pocket and pulled out a ring of keys. His hands were shaking so badly that the keys jingled like tiny bells.

“What are you doing?” I asked.

“Locking it.”

“From this side?”

He ignored me and tried key after key in the brass lock. None fit.

Then the knocking started again.

Three slow knocks.

Mr. Keller froze.

A voice came from behind the door.

Soft.

Female.

“Martin?”

My landlord stepped back as if he had been slapped.

“Martin,” the voice repeated. “I know you’re there.”

I looked at him.

“Who is that?”

His mouth opened, but no words came out.

The voice behind the door sighed.

It was a sad sound. Almost human.

“Martin, please. It’s so dark.”

My landlord grabbed my arm hard enough to hurt.

“You need to leave,” he said.

“What?”

“Now. Pack a bag. Stay somewhere else.”

“Are you insane? What is behind that door?”

He looked at me then, and I understood something horrible.

He did not know.

Not exactly.

Before I could ask anything else, the doorknob turned.

Very slowly.

Left.

Right.

Left again.

Mr. Keller whispered something in German I did not understand and pulled me toward the front door.

That was when the voice changed.

It became my mother’s.

“Daniel?”

I stopped moving.

My mother died when I was sixteen.

Cancer took her slowly, then all at once. I had forgotten many things about her over the years, but not her voice. Never her voice.

“Daniel,” she said again from behind the door. “Honey, please help me.”

My landlord tightened his grip.

“Do not listen.”

I could not breathe.

“Mom?”

The door creaked.

Just a little.

A thin black line appeared between the door and the frame.

From inside came a smell I remembered instantly.

Lavender soap.

Hospital sheets.

Rain on the day of her funeral.

My eyes filled with tears before I could stop them.

“Daniel,” my mother whispered. “I waited so long.”

I pulled away from Mr. Keller.

He slapped me.

Hard.

The sound cracked through the apartment.

I stumbled back, stunned.

“Listen to me,” he hissed. “That is not your mother.”

The door opened another inch.

Behind it there was no room.

No closet.

No hallway.

Only darkness.

Not the kind of darkness you see when the lights are off.

This was thicker. Deeper. It seemed to move slightly, like black water.

And from inside it, my mother began to cry.

I hated my landlord in that moment.

I hated him because part of me knew he was right.

And I hated him more because another part of me still wanted to open the door.

He dragged me out of the apartment.

The second we crossed the threshold into the stairwell, all the sound came rushing back. Cars outside. Someone coughing below us. A dog barking in another unit.

Normal life.

Behind my apartment door, something slammed.

Once.

Twice.

Then came my mother’s voice, muffled now but screaming.

“Daniel! Don’t leave me again!”

I spent that night in a hotel.

Mr. Keller refused to explain everything. He only told me that apartment 6B had been renovated in 1998 after a fire. Three people had died in the building before the fire department arrived.

One of them was his wife.

Her name had been Anna.

The next morning, he called a priest.

Then a locksmith.

Then two men I had never seen before, who arrived in a van with no company name on it.

They went into my apartment together.

Only one of them came back out.

The priest was pale and shaking. The locksmith had blood on his shirt. Mr. Keller would not look at me.

“What happened?” I asked.

The locksmith pushed past me and left without his tools.

Mr. Keller handed me an envelope.

Inside was cash. A lot of it.

“Move,” he said.

“What about my things?”

“Leave them.”

“Are you serious?”

He finally looked at me.

His eyes were wet.

“The door is gone,” he said. “But now there’s a window.”

I did not go back.

Not for my clothes. Not for my laptop. Not for the box of photographs under my bed.

I found another apartment across town. I changed my number. I tried to forget the whole thing.

For a while, I almost did.

Until tonight.

At 2:13 in the morning, I woke to the sound of knocking.

Three slow knocks.

Not from my front door.

Not from the hallway.

From behind my bedroom wall.

Then my mother’s voice whispered:

“Daniel, I found another way in.”