The darkness has a name, but I don’t know that yet. All I know is that I’m scared.

　　I’m sitting with my feet in a creek in the scrubby mountains southeast of Ashland, Oregon, watching how the water spills over gray rocks into a shallow pool. All day long, I’ve been alone and unplugged, doing my best to savor moments like this one. I note how the sunlight filters through the black oaks and flickers in the water like coins in a fountain. Colors get special attention: the denim-blue lupines, the amber grass, and the plum-colored mountains around me. I squirrel these images away to return to later, like nuts before winter.

　　A forgettable dirt road follows the creek out of Cascade-Siskiyou National Monument, which surrounds this place, but that’s as much as I’ll say about the location. A lot of famous people keen on their privacy come up this way, but even plebs like me are welcome. Once you’re here, you have to become no one anyway. In a metaphorical sense, which doesn’t feel metaphorical at all, you must be ready to be buried alive.

　　I walk slowly, deliberately, uphill to a small clearing ringed by aspen and oak. The anxiety that’s been ricing my lungs turns steely and sharp when I see a pale wooden door built into a hillside, framed by lava rock. It looks like the entrance to Bilbo Baggins’s house. I go in. A stairway tumbles down to a windowless, 300-square-foot room with textured walls, a bathroom, and a wooden bed that smells like sage. A single low-wattage bulb hums faintly overhead. It’s controlled by a switch covered with a hard plastic guard, which makes it difficult to turn off and on. That’s the point.

　　This room and two others like it in these secret woodlands are the heart of what might be the country’s only established commercial dark retreat. This is a spiritual place, where visitors pay good money to spend long periods of time in crypt-like blackness, devoid of all light and most sounds, in an attempt to uncage their minds and, they hope, discover something deeper within. I’m here to give it a shot, but the mere thought has left my hands clammy and my breathing pinched. I flip the switch to see just how dark the dark is, and terror presses into me like 13,000 vertical feet of seawater. I implode and race outside, gasping.

　　All humans know the feeling. This isn’t the dark of the inside of a tent on a moonless night, when the forest sways in purple starlight, nor is it a creepy basement where a thin ribbon of light can weasel under the door. You can feel this kind of dark at a place like Carlsbad Caverns, where 830 feet under the New Mexican desert, the rangers turn off the lights and let the children scream. It’s the kind that triggers some atavistic line of code that sends your amygdala rag-dolling over evolution’s awful ledges. How can I survive this? How can I escape it? And the worst: What else is in here, and is it hungry?

　　Evening comes. Time to be brave. I take one last look around outside and gather a few more nuts. A mountain chickadee twitters about. Deer slip through the grass. I go inside and seal myself into the room with a few necessities I’ll be able to locate by touch. A toothbrush. A Hydro Flask. A gray cotton onesie my wife got me for Christmas, because of the way it feels and smells—two senses the dark can’t steal. I light a small candle and turn off the overhead light, hoping to feel a sense of control for one last minute.

　　You can do this.

　　I blow out the candle and swallow the panic as the enormity of the situation settles in. My eyes will never adjust to this. Today is Sunday. It’ll be Thursday before I see a single photon again. That’s 82 hours, alone, in the absolute absence of light.

　　I can’t think about any of that now. Instead, I go to bed early and pretend everything is all right. But it isn’t. Things are about to get really, really weird.