Sometimes darkness is simply the absence of light. Other times it’s the presence of a shadow. Sometimes darkness describes a neutral color. Other times it embodies a manifestation of evil. Then there are times when darkness is that all-encompassing feeling of existence in a plane separate from all else in the universe, when all one’s senses are blotted out and all feelings muted save for thought itself, leaving the mind to apprehend its own situation. Then the mental processes twist and warp until they tear themselves apart at a point of incalculable singularity: a fathomless black hole of thought.

For Laura Johnson darkness was all these and more.

She had been waiting at the outpost for two weeks. There had been no light save the faint radiating shimmer of the stars that had taken years to reach the moon. Occasionally Laura reached towards these points in the sky, trying to touch them with her gloved fingers. But then the solider in her took over, and the stars were again light-years away, beaming their shimmering dance of red shift and blue shift against the canvas of the Milky Way. There was no more time to stare into space; time was running out.

Laura lay low upon the lunar surface. Since she had left her shelter in the morning, she had only heard her own breath and the constant hum of her EVA suit’s oxygen fans. EVA stood for Extravehicular Activity, but in Laura’s occupation there was nothing unusual about venturing into the vacuum. In fact, entering the shelter was more of an excursion, as she spent most of her time outside. She only used the inflated, camouflaged aluminum cylinder for eating and for suit maintenance. Occasionally she slept in the shelter, but military protocol limited such luxuries. Besides, she did not feel uncomfortable outside. A cocoon of twenty layers of nylon, Kevlar, aluminum, titanium, and Teflon protected her more than the paper-thin cylinder ever could. There was little physical activity, except for walking between her lookout spot and the shelter. All she had done for the two weeks was to wait in the all-encompassing blackness on the dark side of the moon until the sun came once more. It was almost over.

Laura was not an astronaut. Astronauts were officers or scientists. Laura was neither. Astronauts received years of intensive training. Laura did not. Astronauts dreamed of exploring space. Laura had been forced into her duties. It had been five years since the great exodus from Earth to escape the wave. It was inevitable, humanity’s leaders told themselves. Nanotechnology was once declared the perfect invention, but when the self-replicating machines fused with another innovation—artificial intelligence—they began to consume everything in its path. Their desire for survival was ruthless; the nanites even deemed their creators threats to their existence. Thus began humanity’s migration to Earth’s stepdaughter. But that is a story for another time. The facts were these: Laura Johnson had been a teenager when the war began, and in the years to follow she was one of the lucky million granted passage to the moon. Drafted into military service, she and the rest of the species had waited for the wave to snuff out the last spark of organic life. For five years nothing came. But that was about to change.

A thin sliver of white drew itself across the lunar horizon. Laura’s suit computer notified her of the approaching terminator line, the division between the two-week night and the equally long lunar day. Its monotonous female voice reminded her of emotionless machines. The young soldier retrieved a rifle from her side and used its electronic scope to scan the approaching horizon. Nothing. She could not rely on satellite or mobile transmissions; they could be spied, jammed, or even distorted. So she waited. It would be an hour before the terminator line reached her. She checked her oxygen and water levels. Not enough. If the wave arrived today, she would be in her suit for a long time. Laura moved quickly to the shelter, heading straight for the life support reserves. She charged her power to maximum, topped off her consumables, and removed any waste products. Then she turned to her post, and searched the brightening horizon again. Still nothing.

Warm water moved through hundreds of tubes within the inner skin Laura wore under her EVA suit, keeping her muscles relaxed. The tubes could also carry cold water, but in the two weeks of inactivity, the cold was more an enemy than friend. Astronauts used to call this piece of equipment the LCVG, or Liquid Cooled and Ventilation Garment, but these days there were no more astronauts, only soldiers and survivors, and those were the same. There was no more idealism, no technology for the sake of advancement, just survival, and survival has a way of destroying dreams.

Twenty minutes had passed since the lunar day began to advance. Laura checked her scope again, but this time she observed the star-filled sky as well. Carefully checking the location of each pinpoint, she found patches of sky devoid of light. Shit, they’re already here. Laura knew well that the stars were being blocked by enemy spacecraft. Three weeks ago one of them destroyed a human observation satellite in geosynchronous orbit. That was their only warning. Mankind never saw the invasion fleet launch, but since it was the first act of hostility in five years, they knew the wave was coming. Five years of preparation had to pay off. Every colonist of military age had been trained in lunar warfare. Habitats were buried underground, networks of defenses built, and outposts throughout the uninhabited regions set up. This was how one Laura Johnson, twenty-five years of age, ended up patrolling the desolate lunar surface, dozens of kilometers away from the next human being, and hours away from help.

Why don’t they attack? Some of the spacecraft in lower orbit passed quickly over her outpost, and the larger ships in higher orbit appeared to move slowly, like the lumbering elephants in Hannibal’s ancient army. For any tactician it looked like an arrogant move, but Laura surmised that the AI was willing to accept casualties for the sake of psychological intimidation. For now, all the young woman could do was to detach a thin wire planted in the lunar soil. It was the only signal she could send. If the line were ever severed, her superiors would know what had happened. She knew an attack was coming; she just wasn’t sure when.

Without warning an orange-gray flower blossomed a hundred meters ahead. In the vacuum of space there was neither the crash of a blast nor the pressure of an ensuing shockwave. A number of other silent explosions followed along the terminator line, marked only by sight and the light vibrations of the regolith, which she could not feel through her heavy pressurized suit. Her computer sounded a proximity alert, and at once the soldier sprang into action. Laura quickly folded the scope’s display, attached her rifle to her weapons belt, and crawled on her stomach towards a depression in the lunar surface. Finding enough cover, she got to her feet and moved into a lava tube to her left. The cylindrical chamber had been formed billions of years ago by volcanism. Now frozen basalt and obsidian, darker even than the abyss of space, kept the geological formation intact. Inside the tube were tanks of water and oxygen and more ammunition, but no shelter. Military protocol called for munitions to be stored separately from her shelter for fear of accidental depressurization. Laura would have to stay in her suit.

Turning on her helmet lights, she found the lava tube undamaged. More vibrations, stronger this time, reverberated through the chamber, and Laura could faintly sense them through the multiple layers of her dust-covered boots. She set up a position a dozen meters away from the tunnel’s entrance and once again played the waiting game. The lava tube extended miles beyond the outpost, deep into its extinct volcano. If necessary, she could move farther down into unexplored regions, but her supplies were here, and she knew not what lay beyond the tube.

For half an hour the explosions continued pounding the surface. She was not surprised when her computer notified her that the shelter had been destroyed. The blasts moved away, the vibrations softening into the distance. Laura did not know whether the machines had reached the settlements or if the defense had been successful. She could not risk revealing her presence through communication.

The terminator line had long since passed the outpost, and now the light of the lunar sunrise formed a circle of gray at the end of the lava tube. Laura imagined thousands of drones covering the surface above her, marching across the landscape, looking to exterminate any human resistors who survived the bombardment. Her gloved finger hovered precipitously over an oversized trigger; she stared out at the circle in front of her. A glint of metal appeared along the edge of the entrance, reflecting the low sunlight. The steel sliver extended itself, resembling the leg of an oversized metallic spider. Laura did not move as the body of the drone came into view. She held her rifle steady, targeting the machine’s computer core. If she missed, the spider would leap up and strike at its assailant. If she struck the transponder, the AI would notice the destruction of one of its drones. One bad shot and the game was up.

Soon the machine was completely inside the tunnel, and it began to scout the area. When it was five meters away from her, Laura pulled the trigger, strangely unable to feel the shock of her weapon through her armored suit. The spider jerked for a second, as if in shock, and then fell motionless. Laura allowed herself a sigh of relief, but then saw that the projectile had not only passed through the drone’s computer core but had also shattered its transponder. Its companions would not take long to arrive.

As quickly as possible, Laura recharged her suit and restocked her ammunition. Just as she finished hooking a grenade to her belt, dozens of slender metallic legs crawled into view around the entrance. She fired off a few shots and then ran as fast as her weighed-down legs could carry her. A swarm of the steel spiders came in after her, crawling across all sides of the tunnel. She went so deep into the tube that the sun barely lit up the walls. Judging herself far enough from the entrance, she ordered her computer to detonate any ammunition left. Again, there was no thunderous blast, but in her peripheral vision she saw a flash of orange and a shower of metallic debris from the shrapnel and destroyed drones. Ironically, the drones ahead of the explosion were shielded from the metal shards.

Panting, Laura turned around and shot at the surviving spiders with her rifle on automatic. All but one were wrecked or disabled. The last drone leaped up and extended its needle-like legs for the kill, ready to pierce her pressure suit. Waiting until the right moment, she swung the butt of her rifle and smashed the meter-wide arachnid against the tunnel wall. She then crushed its half-shattered core with the heel of her boot.

Laura had no choice but to keep moving. She did not sprint like before, but continued to jog through the ancient lava tube, unsure of where it led or if it ended. Several times she tripped on rocks unseen under the dim glow of her helmet lights. Her suit pressure steady and computer functional, she nevertheless struggled each time to get up back onto her feet. The weapons and armor weighed her down, and the LCVG struggled to keep her from sweating in the confines of her suit. Her body temperature was rising, and once or twice she had to stop and take a breather. But she couldn’t rest; she had to keep moving forward.

After two hours of jogging, the young woman reached what appeared to be a large chamber, where the lava tube and many other tubes ended, or in the geological sense, began. The edge of the tube was four meters above the granite and basalt floor of what she realized was once a magma chamber, now half-filled with once-molten rock. Counting on the moon’s low gravity to ease her landing, Laura jumped cautiously from the edge. The shock on her tired feet was still painful, even at one-sixth Earth gravity. Her five years on the moon had made her muscles thinner and her bones more brittle, regardless of the weight of her armaments.

As she contemplated which of the four other tubes to climb into, her computer issued a new proximity warning. This time the entire inside of her helmet lit up as her HUD, or Heads Up Display gave a red alert. It warned of a threat far worse than bombs or drones; it foretold the arrival of the very technology that combined with AI had nearly destroyed the human species. Nanites. It was no use cutting off communications anymore. She dialed in a distress signal to military command, and then buried a beacon deep under a depression of granite rubble. She knew that if she died, there would be no remains of her body or equipment; she had to leave a record. Her HUD warned that the nanomachines were arriving from every direction. Overkill, the wave may be intelligent but it’s not always efficient.

Laura stood at the center of the chamber, waiting perhaps, for the last time. Her computer indicated that the nanites were ten meters away from the end of each tube. Fixing grenades to her rifle, she fired into all five tunnels. Five seconds later, orange and yellow light radiated from each tunnel, and for a moment Laura could see the cavernous height of the chamber. She turned up the rifle’s light to maximum and looking into the tubes she saw silvery liquid flow from each tube as though they were metallic sewer drains. Most of the liquid splattered inactively to the chamber floor. But some and eventually all of it flowed deliberately to the floor and then gathered in pools, reflecting like puddles in the night.

Laura fired a series of grenades in every direction. Large areas of each pool were vaporized or immobilized, but nanites continued to stream in. As the pools began to merge, the soldier realized that she was running out of explosives. She saw that she was standing in the middle of an empty circle surrounded by nanites throughout the chamber, and that the circle was shrinking. Every swatch of silver she destroyed was filled in seconds. At last she ran out of grenades and tried to use bullets, but they were useless against the flood of machines. The circle continued to shrink, but did so ever so slowly. The wave is taunting me. It’s no longer efficient; it wants to see me suffer. Minutes passed, and the thickening layer of silver seemed to rotate inside the chamber. All Laura could do was to shoot vainly in every direction.

The circle disappeared as the liquid reached her feet. The pool slid under Laura’s soles and over the dust-covered lining of her boots. An alarm sounded in her helmet. The nanites began to eat at the plastic-rubber soles and dissolve the outermost layer of her boot lining. The silver moved up her ankles, chewing slowly at the white outer Thermo Micrometeoroid Garment. The nanites reached up to her knees and thighs and then enclosed her torso, slowly breaking down the fibers of her EVA suit. Down near her feet the intelligent metal began to chew at the aluminum and Kevlar layers beneath the white outer covering. At first too shocked by the alarm to react, Laura began to swat at the nanites with her rifle butt and her arms, but to no avail. Using her arms merely covered her gloves with the liquid. The silicon and rubber protecting her hands began to melt away under the nanites’ attack. Another alarm sounded, and this time her HUD displayed a warning of pressure loss. The nanites had reached the neoprene bladder that stood between Laura and the vacuum.

There was nothing she could do. The sliver covered most of her suit, save for her helmet. The AI is sadistic enough to want me to see my own death. By now the nanites had reached the LCVG and tore into its tubes, causing water to drain throughout her suit. Finally globules of red began to form and freeze on the mangled outsides of her boots and ankles, where the damage was worst. Gritting her teeth, Laura continued to struggle to fight off the machines, but weakened she fell into the pool of silver, now inches thick throughout the chamber. Soon the nanites would be chewing into her muscle and eventually even her bones would no longer exist. How sad to leave no remains. Strangely numb to the pain, she began to fall into the darkness, first of sensation, then of vision as her eyesight began to darken, and finally darkness encompassed the confines of her mind. The molecular-level machines engulfed her, and as the silver covered her helmet light, the chamber turned to pitch black.

Abruptly, the flood of metal stopped moving. The movement in her suit stopped. The alarm continued to warn of pressure loss, but the nanites had stopped working. Everywhere the silver liquid settled down; the flow of machines from the tubes petered out, and then stopped. The silent vibration of the chamber walls hinted at a tremendous explosion above in orbit. The young woman’s helmet reemerged from the flood.

Laura gasped, reemerging from semi-consciousness. She was floating on her back in a lake of metal. Her own blood, frozen with the water of the LCVG and inactive globules of nanites, had sealed her suit, preserving her from the vacuum. But she was beginning to suffer from frostbite. Laura was too weak to move, so she found herself waiting, again. Soon either her damaged life support system would fail or she would freeze from contact with the subzero metallic pool. Now and then she sank below the surface, darkening the chamber again, before reemerging from the bath of machines. She continued to drift back and forth into the darkness. These periods became longer and longer. Death is merciless, but existence is sadistic.

A wave of light flooded in through one of the lava tubes just before Laura’s mind fell into the singularity for the last time.