The Black Room With the White Line

If one were to tell you of a particular room, modestly furnished with a table, a chair, a lamp offering some scant lighting, you would think little of such a place. Surely, you would not. Even with much of the room draped in deep shadows, such that the concrete walls, the concrete floor, the concrete ceiling, each can hardly be seen at all, you would think little of it. Even with one whole side a deep abyss, impenetrable, you might not think twice. You may wonder at such a place, its purpose, the fear it instills, but only temporarily. What would strike you is the thick line of reflective tape, a white line that stands out brilliantly within its dim surroundings, begging the question of what might happen if you cross it. But such a place cannot be real, can it?
In short, Hope It's Fiction.
Here is the mysterious novel mentioned in previous stories from that old, misty country - a tale that explores the titular name and the horrors that occur within. Why is there such a room? What is its purpose? And, perhaps most importantly of all, what does this obscure novel have to do with the strange occurrences happening throughout that distant, forest-shrouded area. Everyone calls it merely fiction, but how often can such a simple explanation be true?
Enjoy this single story that can be read on its own or with a plethora of hints toward that old, misty country and the denizens throughout.