Kendra knelt at the edge of the vat of fuel. At her feet sat a collection of small plastic tubes filled with the golden, viscous liquid. She grabbed three microscope slides and used a pipette to place drops of fuel on them. Then she sealed the slides placed them in a protective box.

With her samples in hand, she headed outside and crossed the hot sand. The rover lay hidden in a sheltered nook in the rock, far enough away that the caretakers wouldn’t interfere with it. She examined her samples from three days ago. Some tubes she had left open to the air, while others were closed tight. None of them had noticeably changed. Kendra jotted down the results in her lab book and set off in the rover.

While the research station lacked extra protective suits, she had found eye shields and enough cloth to fashion into a scarf. It kept the sand out of her eyes and mouth as she drove. She glanced at the tubes and watched through the clear plastic as the fuel changed color the further she drove from the plateau.

She parked the rover and strode into the lab. Kendra sat at the computer and smoothed back her windswept hair before starting the recording.

“The last few days, I’ve studied the caretakers’ fuel. My investigation so far paints a strange picture: the fuel decays the further it gets from the ruins,” she said. “I’ve left samples near the ruins for up to four days and seen no decay. There seems to be a radius of twelve to fifteen miles around the ruins. Within that range, the fuel stays intact.”

Kendra held up the samples she had collected an hour earlier. “The research station is outside that radius, and the fuel has become darker and thicker. The decay worsens with time. Compare these samples to the ones I left here yesterday morning.”

The latter tubes held a tar-like sludge.

“It may not be a surprise that these are no longer fit for ‘consumption,’” she said, shaking the tubes. “They also smell as foul as they look. But my question is why? Why would this fuel need to be in proximity to the source to work?” She crossed her arms. “Compositionally, the fuel is a mix of many organic and inorganic compounds, but I don’t know yet what components are important.”

Kendra ended the recording and sighed. If she couldn’t figure out how to preserve the fuel, how could she leave the planet? She stood and crossed her arms. It was no use thinking about this until she had more data.

Bria had taken her own microscopes back with her, but the smaller scopes remained in the lab. Kendra set one of her slides in its metal holder and examined the fuel through the eyepieces. She tapped her fingers on the bench and switched to the highest magnification the microscope could provide.

The fuel was marked by fibrous structures and unidentifiable aggregates. She was unsure whether they were a natural part of the fuel or due to its decay. She also found them in the samples she’d taken of her own blood and skin. After pulling out a tablet, she paired it with the microscope and set it to record a time lapse of the fuel.

Kendra rested her head on her arms.

How long could she stay here at the research station before her body broke down like Antony’s arm had? That was why he had lost his arm, wasn’t it? When the machines removed the crystals, they must have tried to heal his tissue with their fuel. Without continual application of it, the tissue decayed. Maybe in his case, it only affected his arm and not his entire body. She hoped so.

She stood. There was more she could do, and she returned to the computer room.

The lab computer’s desktop screen was a mess, stuffed with so many files and folders that finding anything took ages. Bria had been the only one to use this computer; maybe she left behind something useful. Most stray papers on the desktop were related to the Asteraceans, unsurprisingly. Some were written centuries ago. She tucked them away into a folder.

Other papers discussed ancient technologies. Most were reviews or theoretical papers, dealing with long lost or apocryphal tech. These articles discussed ancient energy sources and communications systems—comms that sounded more like some sort of psychic connection than technology. Nothing was terribly convincing, however.

The remaining articles cluttering the desktop were about neurotransmitters—research from the lab of a colleague at Bria’s university. She snorted. “A little light reading, Bria?”

The last file was a draft of a book manuscript, judging by the file name with ‘book draft 9 FINAL.’ Kendra skimmed it and something in the dedication caught her eye.

For Bria, whose friendship and collegial support over these last years have been invaluable to me, both scientifically and personally. With care and gratitude, Isabelle.

Her eyebrows quirked up. So Bria had some sort of collegial friendship with a fellow professor. Or maybe a crush. “You know, Bria, you could have talked to us about your life more. About you,” she said to no one. “Would’ve enjoyed getting to know you as a person.”

The desktop was clean now, though the ‘documentation’ folder stared back at her. She had no desire to reread the lurid details of what they’d found when they returned for her after the cave-in. But in the same folder, there was something called ‘beacon’ which she had glossed over, thinking it was only a short-cut to the computer’s emergency signal program. Instead, it was instructions on activating the tracking beacons left near the ruins. Kendra’s eyes widened.

“Two tracking beacons were left near the entrance to the ruins,” the file noted. That was the protocol, after all. Regardless of what the machines had done with them, the evac team had left supplies for her. Maybe her luck was improving. If even one beacon was intact, she could contact someone outside this planet.

Early the next morning, a faint vibration thrummed through the ruins. She turned over, eyes squinting into the low light. A second vibration passed through the floor. As she reached for the nearby wall, her fingers caught on something jutting out from the stone of the building where she slept. Before she could process what she was touching, images flowed into her mind.

There was a college campus with old brick buildings. Dust motes floated in the light of a massive lecture hall. Students crowded onto the sidewalks, people flowing like rivers down the street. A crystal burst into dust under her fingers, and the image melted into the ruins. The cave-in.

Kendra saw herself moving slowly forward in the memory. A gasp came from a mouth that wasn’t hers, and she heard thoughts.

This can’t be the end. I need to get home. For my students. For Isabelle.

Another crystal burst under her fingers. She opened her eyes as the remaining melted into sand. Kendra scrambled back, away from the wall. The rest of the cavern remained undisturbed, but her stomach fluttered with anxiety. She hurried to find the source of the vibrations.

The sounds emanated from the cavern deeper within the plateau, where the machines worked. They flitted back and forth, laying down plaster for new buildings. The existing buildings had grown taller since she had last been there. The colonnade now supported three levels, with dozens of individual buildings.

One of the caretakers approached her, chirping curiously. She raised her hand to interface with it, and it returned the motion. “Have you seen these?” she asked, calling to mind images of the emergency beacons. “These are important to me.”

It chirped at her again but provided no information about the beacons. Kendra rubbed at her forehead as the machine floated away. They had tossed the remnants of her protective gear into their dumping ground. It seemed likely the beacons met a similar fate if the machines hadn’t repurposed them. But the sand pits were deep and hard to search, and worse, they were near the caverns where the shadow lurked.

Kendra walked through the colonnade, surveying the caretakers’ work. It was beautiful. The columns were carved with intricate patterns. These were not floral but geometrical. The lines were sharper, more angular, and complex shapes interlocked to form fractal patterns.

She climbed the stairs at the back of the colonnade, holding onto the cool stone of the handrail. It was strange. The machines built these structures, but they were the only ones occupying the ruins or possibly the entire planet, save now for Kendra. They didn’t need stairs or railings, and yet they built them, as if in tribute to the people who had once lived on Asteracea.

A plaza occupied the second floor above the colonnade. This was new; nothing like this lay within the cavern they abandoned, the storage capsule that held the decaying ruins. The machines strayed from their duties to build new structures. Whether it was extrapolation based on the buildings that they already knew or sheer invention, she didn’t know. The plaza spanned at least fifty feet, and the glossy stone floor was inlaid with carvings. Lines and curves marked the floor, and Kendra stepped back to see the whole picture.

It was a skyline. The towers in the carving varied in height and overlapped and created a dizzying arrangement of lines. Swirling clouds surrounded the skylines, as if the towers grew straight from the dust of the nebula itself.

It far more resembled the strange towers and swirling nebulae she and the others had seen within the crystals. It gave the impression of viewing another world, reflected in the glassy surface of the quartz. This wasn’t part of Asteracea, as far as she knew. This spoke of outside influence, from whatever presence created the crystals, whatever thing lay sleeping below.

A walkway connected the plaza to an opening in the rock high above the ground. Kendra followed it and entered another set of tunnels. A breeze flowed across her face. Kendra followed the breeze until sunlight appeared through a crack in the rock several feet wide. Cautiously, she poked her head and shoulders through it and peered out.

Above, she saw the sky through many cracks and crevasses in the rock. Below were more of the natural stone steps, some covered in sand and gravel. Areas of the cliffs had been pulverized, and she climbed through the wall.

Twenty feet below, hidden in shadow, was the curved hull of the ship. She clambered down to it, hearing the metallic clang as she knocked her fist against it. Where the sheets of metal had pulled apart, there was a hole, and with some difficulty, Kendra squeezed between them.

She waited for her eyes to adjust to the darkness inside the hull. The space was large, but not immense enough to account for the size of the hull. Rows of blocks about waist high extended up from the floor. Familiar lines and patterns were etched into them, reminiscent of the circuitry in the ruins. She held her hand out to interface with the circuitry, but nothing happened.

The metallic elements of the circuits were missing, leaving only the holes where they had been. As she walked through the rows, she found little else that hadn’t already been picked apart.

A doorway at the end of the room caught her eye. Kendra examined the doors from top to bottom. There was a gap of three or four inches between them. She grabbed hold of them, straining as she pulled them apart. They creaked open far enough for her to squeeze through.

An elevator shaft greeted her beyond the doors. It was a dark pit dotted with large crystals growing several feet across. They lit the way down with an eerie purple glow. The prickling of anxiety down her back mixed with burning curiosity. What was at the bottom?

Kendra tested her weight on a crystal. It didn’t budge. She climbed down, stepping from one crystal to the next. As she reached out for the next, it angled itself toward her, and she pursed her lips, unsure if it was a trick of the light.

A cluster of crystals blocked much of the elevator shaft below. There was a gap in the middle. Kneeling down, she examined the gap to determine whether she could squeeze through it. As she rested her hands on the surface beneath her, the light shifted from purple to a deep red. The crystals further down slowly parted, twisting out of the way. She followed the steps downward as they created a spiral staircase. The red glow lit the rest of the path as she touched the ground.

Another door stood before her, and she wrenched it open. Faint light illuminated the towers of familiar buildings. She found herself in the abandoned cavern, the storage capsule that held the Asteracean ruins that the caretakers sealed away.

Behind her, the crystals lit the wall with their purple glow, veins of light undulating inside them. Shadows moved on the ground, and Kendra’s apprehension returned in full force. The sense of a presence nearby intensified, that same feeling of being in the room with a sleeping person.

She backed away, weaving between the Asteracean ruins. Climbing the stairs, she reached the platform overlooking the room. But new crystals hung down from the walls, criss-crossing over the path out. Their purple light cast strange shapes on the wall.

Body tense, Kendra slunk between them, crouching down and then contorting herself to avoid touching them. A sharp point scraped against her back. The light shifted and air rushed past her. Something soft, velvety, and cool brushed past her.

She ran from the chamber.