Perhaps it was a mistake, after all. Everyone did it back then, in the last Gs of the Third Epoch. It was the new thing, and everyone wanted to be part of something new. Stimulation of any kind was just about all that was left to live for by then. Who knew we'd find the Layer?

       I'm getting it all out of order. That will not do. I can't let my mind wander. He will see; he will know. And then he will act.

       So, I shall return to the beginning. I was born - yes, actually born, thank you very much - about thirteen-hundred years after the advent of space travel. With so many calendars to choose from, providing a date would be useless. I should clarify, though, that by "space travel" I refer to the first primitive boats that carried early man out of the atmosphere of his home world. (I remain annoyed that the name of our ancestral home is lost to antiquity.) So, in other words, I am really quite old.

       By the time of my birth, humanity had deluded itself into thinking it had achieved immortality. This was not strictly true, since people could have the candle of their lives snuffed out by way of any number of pathogens or even simple trauma to their delicate hominid bodies. Certainly, the various processes of aging had been thoroughly researched and brought to a halt. Life could no longer be defeated from within, only from without.

       (Thinking back that far, to my childhood and adolescence and biological maturity is like recalling memories of memories of memories. This is not a sign of senescence, though! Absolutely not! This is natural for those of my age.)

       Gordon, my home planet, was in the Third Ring of the Diaspora, about three hundred light-years from humanity's crèche. It boggles my (extremely lucid) mind that my forebears made that journey - in fits and starts, to be sure - in self-propelled ships. Mind you, this was before tessellations, before funnel-drives, even before the first hopelessly dangerous FTL sleds.

       Like many of my generation - oh, how few remain - I spent decades and centuries at a stretch in stasis, traveling between the various worlds humanity had conquered. In fact, and this isn't just braggadocio, I was part of the first team to circumnavigate Big Blue. (Big Blue was the nickname of the supermassive black hole at the center of our home galaxy.) Think of it! To imagine humanity's confinement to a single star system is an interesting thought experiment, I suppose. But I remember a time when no humans had ever left the Milky Way Galaxy. Fascinating!

       The treads of my rover catch momentarily on a rill of soil. He pauses, metal eyes watching for signs I can't continue. His bleak metal frame floats effortlessly just to the left and behind while I am bound to the soil by gravity. I remember a time I thought of him as a friend. That was a long time ago. A very long time.

       Why do I rehash the past? Most of those in the Layer have no memory of (or interest in) such ancient history. The other one-in-a-trillion - my peers, my colleagues in survival - know it all too well. Perhaps I remember it for him. In his dark, silent way, I know he understands.

       So ended the First Epoch. We certainly didn't explore every planet and moon and asteroid around every star in the galaxy. But we did map them all, 161,343,194,884 of them. (I can't remember the names of my biological parents, but that number is burned into my brain.) That achievement sparked a party that lasted almost a milli-G. (The children of the Layer don't know what a G is: the time required for a single galactic revolution.) We were so pleased with ourselves. By this point we were encasing our bodies in diamond-scales and breathing through nano-filters. Immortality was almost a reality. It would have taken a run-in with a stellar body to kill me then.

       I look over at him. Best not to give him any ideas.

       Is this hill getting steeper? It's taking most of my will to push the rover up the incline. Don't fail now. Not yet.

       Of course, by that time, once the Galaxy had been dominated - and that included the handful of other sentient beings we'd run across - interstellar travel was simple, affordable, commonplace. And that's when we realized we needed to truly sail the cosmic ocean and leave the galaxy. A thousand light-years in an eye blink wasn't fast enough. We needed to be able to travel a million light-years in an eye blink if we were to colonize the rest of the universe. I certainly had the time, but I didn't have the aptitude for that kind of invention. Others who folded their minds in on themselves in freakish psychological knots unlocked the deepest secrets of the universe. I don't even know how a tessellation works. I think it has something to do with sliding into the twisted geometries of the eighth - or ninth? - dimension and squirting out at some unimaginable distance. The trick wasn't getting the technology to work. The trick was transmitting living beings this way.

       No one ever managed that trick, now did they? I wonder if, somewhere in the cold expanses of the universe, there are still colonies of biological humans, with beating hearts and pumping lungs. I wonder if they still procreate with DNA rather than with psychotypes. Is it better to pass your genetic faults on to your children, or your psychological shortcomings?

       Some of those who have a philosophical bent have asked the question: Are we human? I'm here to tell you I am. I may not have a brain anymore, but I have a consciousness matrix of thasers and argon-silicon crystals that experiences everything - anything - a biological human could. Like fear.

       The hill has to be steeper. It was never this hard before. He hovers, waiting for his moment, the moment to fulfill the destiny I gave him. That impassive, featureless head - save for the glowing eyes - shows no emotion, neither charity nor passion nor greed. It does show patience, endless patience. I wonder what he'll do when the deed is finally done? How will he celebrate?

       The Second Epoch was long, so long. We traveled the length and breadth of the universe. At some point it became more of an event to meet another human than to find a planet made entirely of copper or a ring of liquid water circling within a star's habitable zone. There are only so many configurations a star system can take. There are infinitely many kinds of people. We became our own best audiences. Someone - I never learned who - decided that merging the psychotypes of two or more people wasn't the most efficient method of reproduction. We evolved into sentient protozoa, splitting down the middle and creating exact duplicates of ourselves. We had to do something. It was all falling apart.

       The short-lived, hot stars vanished first. There weren't the concentrations of matter to fire them up anymore. Oh, we could - and did - build vast arrays of machines to force the stellar nurseries back to life. But what was the point? Nothing could stop the universe from unraveling. It had expanded too far. The Big Bang was simply too powerful and there wasn't enough matter to pull it all back in again.
Deeper and thinner and colder the universe became. When the last star winked out, the Third Epoch began.

       How do you entertain yourself when you're a self-contained, immortal entity floating in a dead universe? I'll admit it; I did terrible things. For some period of time - was it years or centuries or eons? - I simply destroyed every other person I met. We were spread all over the still-expanding universe, so just meeting someone was an event. What better way to mark the occasion than senseless murder? When I went through a dry period with no contact, I made copies of myself, and then killed them, too.

       Maybe I deserve what he will do to me…

       Finally, a message - not traveling at the poky speed of light, of course - rang out through the dark, endless night. One of my peers discovered the Layer.

       I wish I was in the Layer now, but I'm not. I'm climbing this forsaken hill on this rogue planet back in the decayed universe of my birth. He makes certain of it. What will he do when the planet itself has dissolved into a homogenous mist of disassociate quarks?

       How to describe what it was like to find the Layer to people who have lived for such a long time in it? Where the universe was diffuse and nearly empty, the Layer is stuffed with energy and matter and life. Where the universe drove us to desperate extremes, the Layer invests us with glorious calm. Philosophers - them, again! - ask the question: Is the Layer heaven? It is for me.

       But I've gotten it all out of order again. That's not good. No, I skipped the step where he enters the story. As time wore us down and our sanity began to chip and shatter, those few of us within communication distance determined a new mode of destruction to liven our lackluster days. We each built for ourselves a companion - such a soothing, docile word for the horror that has dogged me for unmeasured eras of time.

       The idea was this: we certainly did not have it in us to commit suicide. A million-million years of evidence showed that definitively. But we couldn't imagine simply… enduring for all time either. Thus was born the concept of the companion. It was really quite simple. A robot, built to be as indestructible as ourselves, was tasked with following us at all times, monitoring our minds and our will power. If either should falter - either insanity or paralysis - the companion would destroy us. Once activated, the robot would not accept reprogramming, from its owner or anyone else. No longer would we have to live in fear of unending, unmotivated existence. We didn't know about the Layer, of course. We didn't know that soon hope would return again, that life would once again be worth living.

       The young in the Layer look at us with sadness, but they do nothing to save us from our self-imposed death sentence. I believe they will be glad to see us go, glad to see the end of our dim remembrances of the universe, and the end of the steely visages and the blocky outlines of our companions.

       Each of us designed the requirements of our own companion's programming. Some required their companions to validate sanity through feats of mental acuity. Other companions test the physical abilities of their owners through tasks devised a thousand Gs ago.

       My companion does both. He monitors the run of my thoughts, searching for signs of the inevitable breakdown of sentience. He also puts me through a grueling gauntlet once every milli-G, forcing me back to this dead world, making me climb this hill. Someday, if my mind doesn't snap first, someday I will no longer have the mental power to drive this rover over the rough ground, up the slope, to the top of the hill. Someday he will determine that I no longer deserve life.

       The last bit of the journey seems the hardest as my treads grind through the silty gray dust to reach the crest of the hill. His mode of operation changes subtly, too subtly for anyone without my experience to notice. Gone is the intent watchfulness for signs of weakness. Now, he simply attends. Or seems to. He continues to scan my psyche, always, every moment.

       I did my job too well. I cannot - though I have tried a million ways - defeat him. I cannot outrun him or deactivate him or fool him with some clever ruse. He will follow me with blind devotion until my dying day, a day of his choosing.

       Will that be the saddest day of my life?

       Or the finest?