This is a system-wide radiation warning.

The most recent solar flare exceeds nominal parameters by a factor of two and climbing. Exposure levels on the surface of Stygia are considered unsafe for spacesuit ratings up to Cat. III. All scheduled extra-vehicular activities are to be postponed until further notice. Surface facilities are advised to scram any unshielded fission reactors and relocate personnel in emergency shelters. Ships equipped with geometry drives are advised to seek shelter in planetary shadows. Expect widespread scrambling of radio coms as well as an increase in ghost signals.

This warning will remain in effect for the next six hours.

Signed: Bubbles (Mansa Musa class cargo ship Io and Behold).

Be it in the solar system or five hundred lightyears out in the black, radiation exposure is always at the back of a spacer's mind. The thresholds are easy to remember. A tenth of a millisievert is a simple X-ray exam, one millisievert is the highest acceptable dose for long-term exposure on stations and off-world habitats, twenty millisievert is the upper limit for orbital workers, averaged over five years. Around a thousand millisievert is where you start experiencing symptoms of radiation sickness, while anything above ten thousand is instant death. In-between, you are looking at increasing chances of developing cancer over time, as well as decreasing immune response and increasing organ failure rates. The constant flow of high energy particles through space is the ticking clock that determines our careers, our lives, and our fates; there hangs the frontier between the black and the blue, between the gamble of pushing for a few more years in space and the safe bet of returning home before the void gets you. Radiation is also why Stygia should be devoid of life, though it isn't, because it wasn't born under the puny glow of this brown dwarf.

When the flare hits the desolate plains, the radio dies instantly, but the instruments panel on my rover's dashboard does not even flicker. The old six-wheeler comes from the Moon and has seen a thousand solar storms. It is reinforced with lead panels sandwiched in water ice. Even at the heart of the flare, the few stragglers that find their way inside are barely enough to wake my wrist counter from its slumber. The screen gleams in green, but I know that I'm not fine -- this is only the short-term exposure, measured over the last two days. If I switch the counter to its long-term exposure display, the green light turns to orange. Half a year ago, I was careless. I attempted a black box recovery inside the derelict of a deep space probe, not accounting for the presence of a damaged radioisotope reactor. Thirty seconds of close exposure were enough to give me half my lifetime dose. When the counter goes red, my career in the deep black is over.

I curl up on my pressure bed and grab a book. There is nothing else to do when you are stuck in the middle of a cold desert that orbits a failed star, eighty lighyears away from the nearest inhabited world and with disabled coms. Even the laser network isn't available, as all satellites have been sent to the dark side of the planet to weather the storm. The first time it happened, we were taken by surprise -- flares are rare around brown dwarfs, and Stygia's aborted sun was long thought too small to generate them. Five satellites lost, heavy radiator erosion on a Mansa Musa and light radiation sickness in our hydroponics were enough to teach us safety.

My library comes from the four corners of the Traverse. The non-fiction section -- applied ecology, mostly -- originates from Elora, the second-hand comic books were bought on a passing Farseer Transporter, and the Low Age dime novels have travelled all the way from Earth. Their quality leaves to be desired -- I really don't enjoy how the Golden Shadow trilogy ends, though I've heard the author's career was cut short by a hypercane -- but I don't want to let go of their well-worn covers and the myriad of ghosts that once flipped the pages.

One hour into the flare, a burst laser signal reaches the rover. It comes from the Antelope, the Starmoth Initiative surveyor that hangs at the very edge of the night side.

“Hey, Taiwo. Bubbles on the line. How are things?”

“Boring.”

“I've got something for you.”

“It's the signal, right?”

“Yes. It's transmitting again on the edge of my horizon. Same frequency, same pattern, but I don't have any remaining satellite on the day side to pinpoint the origin. You're the closest rover, mind checking it out?”

“How far?”

“You're thirty kilometers to the suspected emission area.”

“I'm on my way.”

I rev up the engine and begin making my way through the plains. Stygia is a dead ball of deserts and marshes with a vague suggestion of an atmosphere and, deep below, a layer of sediment belonging to what once was an Earth-like planet. Our survey team is the only human presence on this world, yet each flare brings out a faint signal from the day-side plains. As far as I can tell, it has been going on forever and precedes our arrival. It is a beautiful enigma lost in the ocean of questions that surrounds Stygia. We know that it was ejected from its temperate system by a cosmic cataclysm, then, after millions of years spent drifting in the deep black, captured by the brown dwarf. The aborted sun warmed it until a new ecosystem developed -- a chance in a trillion, the rebirth of a doomed world from bacteria hidden in the depths of the mantle. We have found vestiges of a complex civilization on Stygia, iron tools, bronze artifacts, the shadows of farms and cities under the icy rubble of the night side. Higher in the geological strata lie the remnants of a more recent and desperate attempt at survival. Bunkers with granite walls, built at the edge of the crust. Geothermal sinks providing heat for now-collapsed shelter cities. The pusher plates of ancient Orion drives, scattered between the mountains of the equator alongside re-entry trajectories following a failed ignition. The skeletons we found hint at six-legged humanoids, though we do not know if these were the builders of the spaceships or merely cattle. Did some of the ships escape, thrown out into the deep black, now founders of a myriad sister civilizations on uncharted planets? We have no way of knowing. Orbital mechanics make it impossible to retrace the path of Stygia, let alone of its wandering arks, if they ever left the ground. We have yet to reach any of the bunkers, yet radar imagery is implacable: nothing awaits us here but corpses and sterile rocks.

I know that the most likely origin of the ghost signal is an unregistered human probe, but Bubbles has found that its waveform is not dissimilar to the frequencies used on the eons-old Orions. It is most likely the result of technological convergence, but the mystery is tantalizing, and I am too vulnerable to enigmas to resist it.

The radiation storm prevents the autopilot from working -- it needs GPS reference points, and these are currently cowering on the other side of the world -- but I know the desolation like the back of my hand. The radio is but a sea of white noise. I pass by the First Landing memorial and its small refuelling lander, then keep going for a few kilometres until I reach the exact centre of the geographical marker. The marshes do not reach this far north. There is nothing but mountaintops that protrude from the calcite dust, the ghost of a much bigger range kept in place by the death of erosion and plate tectonics a million years ago. The brown dwarf hangs in the sky, amber and regal. I can still track the signal, despite the interference. I stop my rover in the middle of a shallow crater, right at the edge of a dead swamp, trees like the hands of a hundred stopped clocks, frozen in place by a change in axial tilt a few thousand years ago. Ice seeps from the ground, mixed with oil and decaying material. My lidar can't gauge how strong the ice is. It is common to find large air bubbles trapped in the surface layers, their domes ready to collapse. The origin point is very close, perhaps half a kilometre out, but I can't risk the rover in this minefield.

I get back to my dime novels and wait the flare out. Four hours later, I step down the rover in a pressurized suit and waddle my way through the dead swamp in a straight line, until I find something.

At first glance, it looks like a miniature submarine. Its surface is pitch-black, with a single, golden eye turned towards the dark sky. It is yearning from freedom that its puny locomotion system -- a pair of air jets, supplied by gill-like slits, and bony tentacles -- cannot grant it in a million years. It is not alive, nor is it dead. It exists in the liminal space between rocks and viruses, a machine of geology cast inside the shell of a grotesquely smoothed-out animal. Through thin gaps in the coat of grime that covers the tentacles, I find streaks of limestone dust and granite debris stuck in the outer skin. My ground-penetrating radar indicates that the thing is three hundred meters long. There is no visible end to the borehole it occupies. The creature has been standing upright in its escape tunnel for centuries; a pseudolichen colony grew through one of the slits, turned into a small tree and then died, a process that takes at least half a millennium. A quick scan from my multispectral suite shows that the eye is a rudimentary communication device, perhaps a beacon of sorts, with copper wires embedded inside the biological structure. I can only guess as to what happens every time the brown dwarf flares. Passing through the atmosphere unmolested, charged particles interact with the circuits and, for as long as the storm rages on, a garbled message darts towards low orbit. It must be calling for a rescue craft that will never come.

As my eyes adjust to the darkness in the creature's shadow, I make out a motif imprinted on the skin. Glyphs and cuneiform symbols, drawing a fresco of distant meaning.

“Bubbles, you there?”

“Gathering my satellites.”

“Can you run a quick translation for me? I've found the origin point, I believe it's a Sequencer, but I'm not sure of the exact subspecies. There's writing on the skin.”

“Send it through.”

I start my camera and send the recording through the laser channel.

“You are correct, this is indeed Sequence script. Orion Arm branch, I believe, dated between one and two million years before present. Your Sequencer is a shambler, from the looks of it, a worker if you prefer. Probably sub-sentient. They're not durable, they die and decay after a few hundred years, until stored underground, so this one was probably hiding beneath the ice. The closest active Sequence world is two thousand lightyears out and has been embroiled in a bacterial civil war for the past hundred thousand years, so we are not dealing with a straggler or an explorer. It is likely this shambler was introduced to Stygia before the planet was captured by the brown dwarf. Perhaps even before it left its original system.”

“Can you make something out of the script?”

“It is full of verbs, and I am not certain I have the right references for the words…hold on. I think the first glyph is a simple expression of motion. Movement towards a single place. The second is the universal symbol for a planet. The penultimate one is a signifier for a group of organised creatures that work towards a single goal, with the added concept of being on the receiving end of orders. A corps, if you will. A unit. And finally, the service sign, which signals a civilian purpose, if the term even makes sense for the Sequence. My best translation would be public works.”

“So that would be…”

“Public work, corps of shambler-engineers, planet-mover division.”

I glance at my screen -- the short-term exposure dial has turned yellow, some stragglers must have seeped through the rover's hull. I turn to the brown dwarf; I could swear it's mocking me.