Sometimes the dreams are wonderful, and sometimes they are living hell.

There are times I walk in the Eden of olden times, when the world was green and the wind made racing waves across the steppes. I was there not long ago, it seems, standing in the clean wind under a warm sun, looking across the land, rolling away to the spine of the Urals—the mountains that bisect Europe from Asia—white against the sky. I could forget for a while the reality of matters, luxuriate in the sense of the primal Earth, its air so kind upon my skin. There were birds on the wing, horses upon the green sea, and the world was good.

I remember those dreams fondly, and know the AI tries valiantly to foster such memories, to damp down the nightmares—for when they break through it seems they endure for months, years, and my sanity staggers in the grip of images I would sooner forget. Only when I am fully conscious can I deal with reality by a philosophic feat, for who could endure the ongoing vision of those green lands made desert, dunes where there had been rivers, a world of stinging wind filled with grit, and where the cities of old were swallowed down deep by the marching sands?

Heat and dust now define Earth, a scorching planet with a broken food web and largely dead oceans. Only the tropical forests persist in the carbon-dioxide-rich air. The oceans encroached upon the coastal plains, 130 metres of onlap worked its relentless destruction upon the doings of humankind, and cities above those elevations are eerie necropoli filled with the bleached bones of billions.

I think it was this horror, more than any other aspect, that taxed my sanity in the endless night of waiting. The AI bridge into my consciousness was linked via the dream cortex, and those dreams dominated me in ways they were never meant to. A clean passage through the alpha brainwave range as I ascended to consciousness or down into the untroubled sleep of ages would have made the process simple, but actually waking was something I could never do.

None of us could, we, the 29,000 souls who survived here.

That was the trick, coming close enough to consciousness for my mind to be in control of itself without my physical body actually waking; the infiltration of dreams was the price, and technicians long ago had warned me I risked madness. But someone must be aware of the world to make the decision to wake, and as director of the project I would leave the task to no other.

How long? The AI whispered to me of decades flowing by, of conditions above slowly changing. Forty years ago it noticed an anomaly on the external visual pickups and correlated observations to reach the astonishing conclusion that energy reaching the ground from the sun had fractionally reduced, as if solar output had lessened. No known mechanism could account for it but recalculation now assumed a slow but genuine cooling trend in our over-hot world.

As the hundred drones went about their repetitive tasks, maintaining the biostasis modules, I saw through their eyes, walked the chill corridors of the redoubt, and consoled myself with the thought that all was in the green—we were alive, and would stay so for as long as it took. My machine memory told me I had paced the catwalks to their modules—Eleyna and Talia—176 times; each pilgrimage was to stand for a while and look down on their faces, unchanging in the gentle arms of stasis, and heave a mental sigh, longing for the moment the march of the years was over and we would be together again.

One can acclimate to anything, and I had come to understand my lot was eternity, gliding from year to year and decade to decade. Thus it was with strange disquietude I felt myself roused from the deeper layers where dreams came less frequently, piloted up through vivid cycles toward the edges of wakefulness, where my mind could reach through and phase with the world once more.

Things have changed, the AI whispered, faster than we ever anticipated. The air is breathable once more.

How—I stammered mentally, but had no time to complete the thought before the real message drove home to me with the force of a cometary impact.

We have visitors.

• • •

Not in more than seven decades had any living thing walked these halls, and I was perturbed by the thought of coming face to face with whoever it may be.

I phased in a smooth, cool dive into the perceptive envelope of a maintenance drone, breathed mentally as if I still had a body of flesh and blood, and flexed powerful metal hands. My vision cleared and I knew at once I was in submaintenance bay twelve, the machine vault where the drones repaired each other. No lights were required, my senses were multiple layers of thermoscan and lidar, supplementing empirical knowledge of the redoubt layout. I had an immediate feed via the AI from the external sensors on the energy towers far above, and a passive imaging system fed me a scene such as I had imagined down the long, dark years but never truly dared expect.

The wind-tormented desert was its dirty red-brown self, the slope down to the dry meanders of the Ural River, here to the west of lost Orenburg, a rippled field of low dunes. A hundred metres from the slowly corroding towers that rose, squat and obtuse, from the desert, stood a craft of unknown design; wing-mounted engines were obviously rotated for vertical landing performance, and from it had emerged four people.

People!

Human beings—living human beings! My heart flip-flopped and I zoomed the lens to examine them one by one. Two men, two women—a tall, broad, Slavic male, a Caucasian male with more western features; one of the women was small, petite and Chinese, the other a flaxen-haired European. This latter was dressed in a rugged jumpsuit of dusty white fabric, the others in what seemed a uniform of simple cut and grey-green tone. They walked with care in the slithery sands, panning instruments as they examined the towers, and I knew at once they had no knowledge of the redoubt—zero information had come down to them, and my curiosity was doubled when I matched this to the mystery of how the external environment had veered back toward human habitable inside the same century as its downfall.

The signal sky was quiet in all the bands we were tuned to monitor, but clearly we had been listening in the wrong regions of the spectrum. These people were technological and appeared healthy enough, healthier than the oxygen-poor air and still high temperatures should have permitted. Perhaps—my digital heart fluttered at this notion—perhaps those who had abandoned Earth had returned at last.

I was unsure how I felt about it, but a current of resentment made itself known. We had held our ground, cloven to Mother Earth, not run away from the mess our ancestors made. It was ours to inherit, and we had every tool and resource in our vast underground chambers to do so when the time was right. But these strangers’ presence posed uncomfortable questions, thoughts that placed our survival strategy in doubt, and this was unacceptable.

With a whine of servos I stepped out of the drone’s service dock and headed for the vertical access. After a seeming eternity of sleeping darkness, I was back—and before all else I was my people’s protector. I rose to a command node on a higher level and woke systems with silent, lightning-fast commands, standing in a ring of projection screens on which data streamed and images played from a dozen perspectives. Here I contented myself to watch; after three-quarters of a century, what did a few hours matter? If they were smart, the visitors would find their way in.

As the day aged toward evening I watched them scanning the towers as if they had no notion of such designs—likely checking for ionizing radiation, and chemo- and biohazards. The structures were merely the upper extremities of a thermal-differential energy installation, whose endlessly circulating freon gas, between the heat of the upper world where it expanded violently and the chill of bedrock where it recondensed, drove generators and provided all the power the redoubt would ever need. It was engineering no more complicated than a refrigerator, but on the scale of a skyscraper, and its sheer simplicity guaranteed longevity. These people from the sky must be looking for something more complex, I guessed, and their perplexity struck me as amusing. But they brought tools from their craft and spent an hour shovelling sand and grit from the base of one of the stacks, and at last uncovered an access hatch.

Now it got interesting and I watched with keen attention as the tall Slav pried open the command panel by the hatch, dismantled the code keypad and scanned the reverse side, obviously analyzing the circuitry. I knew it was just a matter of time before he worked out how to circumvent the entry lockout. I smiled mentally, acknowledging the smarts of our guests, as motors turned for the first time since the complex was sealed, withdrawing tooled steel lugs, and the door swung inward. I felt motion sensors detect the intruders and systems swung into action—LED strips blinked on and fans began to circulate the stale, hot air.

In the sight of discreet cameras, the four penetrated the service way surrounding the heat-exchanger ducting at the core of the tower and began their descent. Now I nodded to myself. It was time. I strode to meet them, aware clearly as they encountered other drones in their rounds, and I ordered the machines to remain impassive at the intrusion.

The long metal halls were chill and echoed dully to footfalls. My sensors picked up voices as I approached, a Russian accent commenting in English as service panels were read: “High-pressure air line ... Condensation recovery duct ... Main A/C harness ... Caution: Hot ... Robot access only ...”

At once the four intruders whirled as I strode purposefully from a turning and eased to a halt before them. The moment was more laden with meaning than even my processors could calculate and I registered their apprehension as they took in my form, head and shoulders taller than any of them, my dull metallic casing stenciled with Cyrillic characters. My optical pickups glowed softly as I scanned them in return, while my human heart sang to behold the living.

“I don’t think it’s hostile,” the Chinese woman whispered after a few moments, and my reaction was a very human twitch of my shoulders.

“Privetstvuyu,” I said, amiably enough, to the Slavic man, who smiled at once.

“Zdravstvuyte,” he returned easily, as I placed my hands together in human manner.

A moment later I switched languages. “Chinese, Russian, European ... I sense English is your lingua franca.” I read their expressions and moved on, my voice slightly metallicized and with a soft Russian accent. I spoke easily but with a reserve perhaps only I appreciated. “Welcome to the South Urals Survival Redoubt ... We have waited a very long time.”

The silence was difficult, and the fair-haired European woman stepped forward. “Doctor Sondra Cullaine, of Prometheus City, out by the moon. I’m in command.”

I extended my hand gently and an emotion for which I was not ready filled me as I pronounced my name for the first time. “Doctor Anton Mikhailov. My body lies sleeping with the rest, but my mind is very much here.”

With the strangest feelings in my heart and belly, I felt her clasp my cold metal hand, and I shook with a soul from my personal future.

• • •

They had torn apart asteroids for the raw materials to build their cities, powered by the sun and the atom, and controlled by EM drives. I wished my drone body was more expressive as I struggled to keep up with the revelations. Using the same technologies, they had placed a vast obstruction in space between sun and Earth, generating an eternal eclipse that mediated in a very controlled way the precise amount of energy striking the planet at any latitude, at any time. This was what the AI had detected decades ago, explaining the trend to a cooler environment. I accepted their explanations, if not uncritically, as the AI surged in its cybernetic vaults, examining the data, crossmatching and modelling.

“Outside oxygen levels are our indicator of the recovery of the planet,” I replied as I led our guests along an interminable corridor in the cool depths of the complex. “The redoubt was designed to survive for many centuries if need be. The terrain is geologically reasonably stable, minor disturbances the engineering can cope with. A hundred drones look after the systems and themselves, while the power will flow as long as the heat differential lasts.” I paused by a long gallery and passed a hand over a control. Metal window shields ground slowly upward to reveal a vista of systems in multiple repetition—and I felt a hand brush my spine at our guests’ expressions as they realized they looked out upon tier after tier of casket-sized capsules.

“Are they biostasis modules?” The European man, Travers, whispered.

“29,000 people lie sleeping below,” I replied simply. “When the O₂/CO₂ balance comes even 10% closer to preindustrial levels, it will be time for them to wake and build a new home.” I gestured with a hydraulic arm. “There I am, on that uppermost tier, number 28062. Beside my wife and daughter … My consciousness drifts in a shallow sleep, my dream cortex linked to the complex’s AI and interfaced with this drone. I am the eyes and ears of the project.” My voice faded, became introspective. In a flurry I recalled the nightmares, filled with thoughts of a burning, angry desert, the decades drifting by with the sand on the wind, the lost race asleep amid the bones of perished nations. My metallic whisper trailed off and Cullaine shared a difficult glance with the Chinese woman, Chan. I pulled myself together. “Still, when this redoubt was built in the first years of this century, we were sure we were not alone. There are others in Russia, more in China, in Scandinavia and Japan, and probably elsewhere also. As millions fled into the sky, those who remained knew any hope of survival lay here, not in the vain dream of joining you Hi-Techers at L5.” I slapped the railing below the windows. “This is the low-tech solution, and we have always believed it was the right one.”

Zaitsin, my countryman, was unreservedly proud of all he saw. He was an engineer by trade, and appreciated the elegance of our solution. “A race in being—people of the late 21^st century who will return and make the 23^rd their own.” He nodded with quiet satisfaction. “The continuity is amazing, and unexpected.”

I nodded silently in return, but raised a cautioning finger. “Be warned, many resented those in the sky ... You ran away from the problems our ancestors caused, and left the rest of the human race to suffer the consequences.” The silence was difficult, and I filled it with a coughing sound. “That was before all your times, I know. But not mine. Though your lives are much extended by technology, none of you was born before 2100, and The End. I have been sleeping since 2105. It is a sad reminder of the chaos of those last terrible years as the world became unable to support animal life, that your people and ours lost track of each other so thoroughly we now meet as strangers.”

Cullaine checked the time display in the corner of her tablet and lay a hand on my arm, the human familiarity making my heart ache and underlining the loneliness I had endured. Her expression I recognized as compassion and in that moment I could believe it was genuine. “Anton ... We can’t speak for those who built the cities in which we were born. But it is our mission and purpose to restore what was lost. The atmospheric balances you are monitoring are responding to our efforts. Do you not monitor the signal traffic between the space cities?”

“We have no means. We were ... unconcerned with the doings of those who turned their backs on us.”

“Then let us show you something amazing,” Cullaine said softly, gesturing to the world above and offering me her hand.

• • •

Evening thickened over the wastelands, a reddish sunset building through the dust, when we emerged on the surface. I looked up at the sky and stretched, the human expressing through the machine; if I could have wept I would have done so now, for never before had I left the redoubt. But my attention was drawn to the east, where clouds boiled in slow motion, and a shape beyond all reckoning lay at their heart.

“We call them Genesis Ships,” Cullaine said, my hand still in hers. “This is the Perun.”

“Perun?” I returned in some small surprise, scanning the AI’s database. “God of storms and head of the ancient Slavic pantheon.”

“Just so. It was rather apt, we felt. In ancient times, storms were understood to be the harbingers of life. Nothing grows without water, and thunder and lightning are the bringers of rain, thus storm gods were often patron deities of agriculture. Each continent has its vessel. Thor works Europe, Dian Mu China, Oya cruises Africa, and Mamaragan Australia. The Americas are tended by Thunderbird and Baka’b.”

As we watched, a great fork of lightning played through the clouds and stroked the vessel, mirrored a moment later from another angle, then multiple strikes to the earth below the craft’s oblate belly.

“The hull is charged,” I observed in an awed whisper.

“The whole vessel is a lightning rod ... In her holds are the systems that read DNA and write out proteins, turning raw materials into life. The seeds of the hardiest grasses, able to stabilize these sands, are made in that ship and scattered to the world below as she raises the storm. Each seeding run strips the moisture from the clouds, and makes the rivers run. A million storms have been triggered in the right places, a trillion-trillion seeds have rained from the clouds, and little by little, we are winning back Earth.”

“However were they built?” I murmured.

“Each took around a year, much of them 3D printed. 1500 metres long, the largest craft ever to move on the face of this world. They were assembled by drones, much like yours. It took a decade to crack out enough helium to fill them, but time is one thing we have plenty of.”

We stood in the last light of day to watch the behemoth creep westward, towing its vortex of cloud and fury, a marching curtain of blue-white strikes writing the furious command to life upon the desert. The rains came in concert, a silver-grey curtain that sent reaching fingers flooding through the dry bed of the Ural River on the slopes below us, and as the titanic craft made its stately passage I nodded my metal head, hands folded before me as my resentment, my apprehensions, melted away and I understood the scope of their achievement.

“The oceans, too, yes?”

“Each has its own vessel,” Cullaine said softly. “Named for the sea gods, as you’d guess. They’ve spent fifteen years writing out the genes and proteins for phytoplankton and raining them into the spring seas. When their proliferation has raised the oxygen levels far enough, we’ll introduce zooplankton. Then the first fish ... From the humblest building blocks of life, the great food web will be rebuilt ...”

“Now I understand,” I said, raising my hands to the vista of the storm and the tremendous, organically curved vessel. “When we sealed ourselves into our redoubt we expected many hundreds of years to go by before natural processes began to repair the damage. A single century now seems more likely.” A sudden elation gripped me, edged my voice with joy as the overwhelming image of the sunset-lit titan, wreathed in lightning, filled the sky before us. “Our own genebanks become merely a failsafe, a reserve. Ten years more and I will awaken our people. They will emerge upon steppes already green with a sea of deep grasses, the Kazakh desert driven south once more. We will rebuild Orenburg and see the first snows return in the highlands. The Ural shall flow once more, to swell and refresh the foul remnants of the Caspian Sea.” I spoke with, more than passion, the sense of prayers being answered, and of gratitude for the revelation to have come upon me when faith was long since eroded by the grinding sameness of the decades.

“It’s the dream of the age,” Cullaine murmured against the near-continuous rumble of thunder, and we felt the first rain spots on our upturned faces. “It’s good to think Earth was never quite as dead as we feared.”

“Life persists,” I returned quietly, and those two simple words were a summation of the will for Planet Earth to endure and overcome all we had, in our ignorance, inflicted upon it.