In any city, in any country, go to any mental institution or halfway house you can get yourself to. When you reach the front desk, ask to view something known as "The Holder of the Voice". The worker may try to hide a brief look of panic, but will eventually compose himself. He will throw you a small, black, unmarked plastic bag and walk away irrationally. You do not have to follow him, but something will bid you to trace his footsteps.
You will pass through a dimly lit hallway with panoramic windows for walls. Regardless of the time of day, the outdoors will appear to be dark. Should you look out the windows you will see only an endless stretch of woods. If you think you see motion in the woods, DO NOT turn. Keep walking up towards the end of the hall.
There will be no door, only a blank wall with peeling wallpaper. The worker will tear the wallpaper off just a bit, then flee into the shadows. When you inevitably finish tearing the wallpaper, a small, dusty attic room will be revealed. In the center sit two objects, a small doll and a tape recorder. Both are ancient and coated in dusk.
If you examine the doll, you will see a small metal crank on it. Wind the crank and the doll will emit a sound somewhat akin to fingernails scratching against wood.
Press play on the tape recorder. It will play even if there are no batteries. There will be the muffled sound of a female voice in distress. You will not be able to make out the words. It will go on and on until you press stop.
The final decision facing you will be whether or not you should play the two sounds together. The bag given to you will contain two rusted railroad spikes. You know what you will do.
The moment you attempt to start both sounds at the same time the ground will begin to shake and the room around you will begin to crackle and start coming apart. If you were to survive the collapse of the building, you will be haunted by a sound so shrill and grating that should you remain listening to it for even a small amount of time, you shall bleed from the ears until death. Even before that, you feel feel strongly compelled to impale both of your eardrums with the railroad spikes.
Your only hope is to, through the evil sounds piercing the air, nail the doll and tape recorder to the floor where you stand.
Should you succeed, within the broken tape recorder, you will find a tape. It is unplayable and emanates a buzzing hum if you listen closely. When the time comes, all held with that tape shall be revealed.
That object is 105 of 538. They must never come together. Never.