Dan stopped. He cleared away a chunk of plaster, and his face went entirely blank. Behind the drywall was a sheet of heavy, industrial steel. It was a massive gray door, fitted tightly into the frame, with a heavy lock that looked like it belonged on a bank vault.

We tried every key Brenda had given us, but none of them fit. That was when we called the locksmith. He worked for forty minutes, grunting and sweating, before the heavy lock finally clicked open.

And then he refused to go inside.

Once the locksmith’s truck rumbled down our gravel driveway, Dan and I were left in the quiet house. The air coming out of the newly opened door was freezing. It smelled like wet concrete, old iron, and something else that made my throat tighten.

I pulled out my phone and turned on the flashlight. We stepped through the narrow metal doorway.

The room was small, about 8 by 10 feet. The walls were solid concrete, showing the rough texture of the wooden boards used to pour them. There were no windows. No ventilation. Just the cold, dead air.

In the exact center of the room, a heavy metal chair was bolted directly into the concrete floor. My chest felt tight as I looked at it. Thick leather straps had been attached to the armrests and legs, though they looked like they had been hastily sliced off with a knife years ago.

On the back wall, someone had scratched vertical lines into the concrete. They were grouped in fives. I shined my flashlight closer and started counting them. My heart was pounding against my ribs.

There were 847 tally marks.

“Dan,” I whispered, my voice shaking. “What is this place?”

He didn’t answer. He was looking at a small wooden stool in the corner. Resting on top of the stool was a black portable cassette player, covered in a thick layer of grey dust. Beside it lay a single, yellowed cassette tape with a cracked plastic casing. This was our sacred object, the one thing that seemed to hold the key to this terrifying room.

I blew the dust off the tape. The plastic felt cold in my hand. I placed it inside the player and pushed the play button. The mechanical whir of the old machine sounded incredibly loud in the small concrete space.

At first, there was only static. A heavy, scratching sound that went on for several seconds. Then, a voice came through. It was a woman’s voice. She was whispering, her breath rattling against the microphone.