The Abaquq exited its translation wake and started burning hard to lock its velocity with that of the dusty moon two hundred thousand kilometres below. The Firebase-class ship was registered as an Algorab long range shock unit. Its livery was white with black outlines and a stylized raven underneath the central pair of radiators. Their faint glow was no match for the billions of stars in the sky. Twenty thousand lightyears away from the Earth, at the edge of a globular cluster, the galaxy was dense and luminous. The bridge was lit in dark blue. The Abaquq was on combat alert. Navigator Francesca Lazward recoiled her seat.

“Weapons?”

The tactical officer glanced at their console.

“South pole ground target acquired, one hundred thousand and fifty downrange. Solid lock on missiles.”

“Hardpoints 1 to 4, fire.”

Four faster-than-light missiles detached from the Abaquq, flipped and ignited their chemical drives. The projectiles darted towards the moon, a few thousand metres ahead of their parent ship.

“Translating for target.”

The missiles disappeared with a brief glow and reintegrated reality at the edge of the moon’s exosphere, five thousand kilometres above ground. They jettisoned their manoeuvring stage and engaged their terminal approach drives.

“Target is waking up. I’ve got thermal pings. Casabas.”

Faint pillars of plasma material started appearing in the moon’s dead sky. One missile, engulfed in a rapid deployment of superheated elements, was instantly obliterated. The three others fired their complements of decoys and kept going.

“Casabas firing again. We’ve lost missiles 3 and 4. Two remaining. Cracking fairings.”

The two remaining missiles opened their fairing and deployed their warheads — ten for each vehicle — while the terminal stages careened into the black.

“Sixty seconds to impact.”

“Close-in defence systems firing. Metal shards, electromagnetically propelled. Some sort of PDC. I count four, on each side of the structure.”

The warheads kept descending. Thirty seconds.

“Two PDCs jammed. Thirty seconds to impact.”

“Twelve warheads remaining.”

“Impact in ten.”

“Five.”

“Impact.”

The surface of the moon trembled. Vast plumes of dust rose up in the razor-thin atmosphere, drawing grey flowers against the red clouds of the gas giant.

“Impacts confirmed. The structure is collapsing on two separate points. Casaba mounts and PDC domes breached and destroyed.”

“Fire hardpoint 1 for recon.”

A fifth missile left the Abaquq, then translated towards the moon and loitered for a few minutes at the edge of its gravity well. Nothing moved. The moon had fallen silent again.

“Recall 1,” said the navigator, “and prepare for drop.”

*

The Abaquq watched overhead, in geostationary orbit. A flight of five support drones and a military lander darted towards the icy moon, black against black. Inside waited a full squad of Algorab operatives. Seven soldiers in full exoatmospheric combat gear, wearing modular ihamora suits and exoskeletons. All of them wore the geometric raven in their neck, near the monad access port. Algorab operatives had a modified monad capable of storing their muscle memories and copying them to an external storage. Even in death, they would pass on their instinctive knowledge to their successors. The group’s leader was a woman of distant Chinese descent named Xiaomai Qing. Though only forty years old, she had lived many a life; when she moved, her gestures weren’t entirely hers.

“Alright, people, listen up. The facility below is a weapon system of unknown origin. Three months ago, it fired a Casaba-adjacent weapon at a Starmoth Initiative vessel and heavily damaged it. The Abaquq has cleared its weapons and external defence systems. We are to land, neutralise the rest of the facility and identify it if possible. Full drone support will be allocated to us.”

They had already been briefed, but Xiaomai Qing liked to do her little speeches before insertion.

“Do we have any idea about the ruin’s origin?” asked Serena Shanxi, their scientific liaison. The young Earthling had eyes the colour of a dead brown dwarf — a q-aug that replaced her natural irises.

“This area of space was once within projected Forgotten Traveller territory, but Casaba howitzers are way beneath their technological capabilities. Starmoth Initiative explorers report the presence of an extinct civilization in this system. Carbon-based, space age tech level, little to no ruins left behind. Pseudofish body frames. Prospective name: the Hidden Steel.”

“Randomly generated?”

“Yes.”

The lander fired its engines and began its final descent. The drones moved forwards, suspended under their sky cranes.

“Helmets,” said Qing, and the seven operatives put their helmets on in a single, synchronised move. Algorab face coverings were optimised for close combat in Sequence ruins. They were multi-faceted like the head of an insect, and covered in miniature sensors.

Qing leaned forwards and whispered. Her voice came through side speakers, and was slightly distorted.

“Who will stand at the gates?” she asked, softly.

“Al-Sayf,” answered the operatives.

“Who will shield the fire?”

“Al-Sayf.”

“Who will stand upon the abyss and watch?”

“Al-Sayf!”

“Who are we?”

“Al-Sayf!”

“Who do we fight for?”

“Raven’s light!”

“I can’t hear you!”

“RAVEN’S LIGHT!”

Then the lander fell silent, and the engines went to full throttle.

The lunar soil was mostly composed of regolith. The lander didn’t have trouble finding its balance — it was made for much harsher environments — and stabilised itself with ease, blowing a cloud of dust that quickly settled down. The sky cranes dropped the drones and ascended again, deploying decoys in their wakes but no projectile darted towards them. Twenty kilometres south, the facility remained silent.

Xiaomai Qing made landfall first, once the combat drones had scanned the area and showed it to be devoid of hostiles. They were Shilka-class combat frames, optimised for Sequence combat. Geometric, six-wheeled, they moved swiftly despite their size.

“Radio check,” announced Qing.

“Liaison Shanxi, checking in,” answered Serena.

“Weapons specialist Carter, checking in.”

“Weapons specialist Delcourt, checking in.”

“Drone operator Zhiyi, checking in.”

“Demolition specialist Alvarez, checking in.”

“Recon specialist N’Mani, checking in.”

“All Ravens accounted for. Ground team, fan out. We’re moving towards the structure. Weapons ready. Drones will take point. Contacts are to be met with extreme caution.”

The drones moved out, followed by the team. Their shadows were sharp and faint, cut out by the gas giant.

Surface gravity 0.2 gees, said Serena’s head-up display. External temperature minus 145°C celsius. Residual atmosphere with traces of oxygen, argon and xenon. It was a dead moon, alright. One among the billions that filled the galaxy. The regolith felt familiar under her feet, and her breath sounded harsh to her ears. She had her eyes locked on the facility to the south. The building was about fifty metres tall and half a kilometre wide. All grey, probably made of regolith, it had something of a raindrop splattered on the surface and frozen in time. The missile strike had collapsed one half of the building, revealing the internal machinery of two of the six Casaba mounts. There were hints of heavier damage inside — shattered beams of regolith, half-molten plasma pouring from the cracks.

“Hey, Serena,” asked specialist Carter on a local channel, “what’s a Casaba Howitzer, exactly?”

“Oh, yes. Well, it’s some sort of rather primitive beam weapon. You detonate a nuclear charge in a specific canister where it vaporises a disk made of heavy metals, creating a high-velocity plasma burst that can reach low orbit.”

The implications were rather peculiar, thought Serena as she provided the explanation. Casaba howitzers were self-contained weapons that already had their own energy source, but nukes were not eternal. They degraded over time, like any radioactive object, and had to be replaced. This meant the facility had a way to mine radioactive material and manufacture new nuclear weapons.

“Serena to squad leader. How old are the Hidden Steel supposed to be?”

“Relatively recent. Reached their apex fifteen to ten thousand years before present.”

“How did they die?”

“Their home planet is the third world in this system. It suffered from a runaway greenhouse effect. No signs of active civilization at the surface. Choked themselves, like so many before.”

Silence came back, sharp as a blade.

The moon was relatively featureless. The gas giant captured most of the system’s asteroids, and there were few impact craters. There were two kilometres left for the squad to cross, and no cover whatsoever. Xiaomai Qing ordered the operatives to stop, and they took a knee in the regolith, at the top of a low ridge. Qing sent a Shilka drone forwards.

“Movement in the building,” said Delcourt. “One PDC still active! Veer off, Shilka!”

The drone braked and went in full reverse while firing a set of gleaming decoys. At the scale of mere human beings, a ground-based PCD cannon was a fully automatic artillery battery.

The Shilka trained its twin coilguns on the PDC.

The PDC took aim at the drone.

Then it collapsed.

“PDC jammed,” whispered Zhiyi, “the beams gave out. Whole place is falling apart.”

“What are these PDCs even made of?”

“We’ll know soon enough. Squad, loose formation, mutual cover, move in. Shilkas on the flanks. Weapons red.”

“What if something jumps out of the ruin and tries to kill us?”

She didn’t answer and they continued in silence.

Radiation levels jumped slightly near the area breached by the missiles, but the squad’s ihamoras were enough to absorb most of it. The shattered Casabas were like broken pillars. The hands of a stopped clock, right under the gas giant.

“Abaquq to ground team. We have you on satellite. What do you see?”

“Transmitting a video feed of the structure.”

Qing stopped. The Shilkas took point on her sides, scanning the structure with their spherical sensor pods. The inside was remarkably simple; beneath the dome, there was nothing but a set of Casabas and the PDC systems. Artificial wells went through the soil. 3D scans showed they likely housed the facilities dedicated to the maintenance of the Casabas and their nukes. In truth, considered Serena, it felt more like a tent than a dome.

“All clear. Residual activity in the wells. Death twitches. I have four breached Casaba units. Radiation is acceptable, but everyone will need a cell-stop treatment after the sortie.”

“Noted. Abaquq out, keep us posted.”

Serena hand-launched a small drone and ordered it to start scanning the surroundings to get a full model of the facility. The walls were made of regolith, as well as most of the Casaba canisters. It was quite a feat of engineering — durable, locally manufactured and easily replaceable. The Casabas themselves were much more compact than what she would have expected for a space age civilization. Qing resumed her communications with the Abaquq.

“Begin recording. Contact with unknown technology, associated with the extinct civilisation known as the Hidden Steel. The facility seems to be an artillery platform, as expected. Seven Casaba Howitzers can be observed, all of the same make and type. Observation of a destroyed Casaba shows that the central nuke area was made to be removable, presumably for replacement. Very few metallic elements can be observed, save for the Casaba plate, which was seemingly made of tungsten. The rest of the weapon is made of regolith. The PDC systems are also built out of regolith, save for the conductive surfaces of the coilguns. The industrial processes through which local regolith was turned into such a variety of materials are unknown, though at first glance, they appear to be more advanced than ours.”

“I concur with leader Qing’s assessment,” continued Serena, “and I would add that there doesn’t seem to be any digital electronics on the weapon systems. I can only see analog computers based on mechanical apparatuses. Part of those systems are also made of regolith. This is very high-tech, though obviously divergent from our own development path. Everything here looks optimised for resilience.”

“I’m seeing two six-legged drones working on a Casaba. They’re probably part of the maintenance system, I assume they can build copies of themselves. Not hostile.”

A brief silence. The coms flickered for a while. The gas giant’s magnetosphere was finicky.

“Abaquq, be advised, there is a reinforced area at the middle of the facility. Fire guidance calculators seem to be exchanging information with it. We are about to enter said reinforced area. Confirm?”

“Abaquq, confirmed.”

“Alvarez, clear up the door. Cleanly, and with a drill, this is not a battlefield.”

Specialist Alvarez and their mining drill made short work of the main access to the reinforced area. The structure clearly wasn’t made to defend against ground intrusions — though Serena couldn’t tell if it was an oversight or by design.

They entered.

“Lights.”

Serena cracked a transparent stick containing a solution of bioluminescent bacteria. This was standard Algorab practice in alien ruins — light emitted by bacteria was devoid of UV emissions that could be harmful to local life or artefacts.

“Abaquq. What do you see?”

“Specialist Shanxi here. The sub-structure is a reinforced dome. Aside from the door, which is made of bricks, the superstructure itself is made from some sort of reinforced regolith. Chemical additive unknown. Analog computers litter the room, half of which appear to be somewhat functioning. There is a set of coffin-like structures in the middle of the dome. They appear to be…Abaquq, please hold on a moment.”

She blinked. There were living creatures inside the coffins. Eel-like, the size of a human being, they were covered in intricate jewels that protruded below sleeve-like void suits. Their helmets were like sacks of transparent tissue, tightly wrapped around their heads.

“Specialist Shanxi to Abaquq, resuming transmission. We have found what appears to be half a dozen individuals, presumably belonging to the species that built this place. The coffins are filled with ice. Holy Earth…specialist Alvarez is telling me that there are faint markers of biological activity inside the coffins. No life per se, but…very, very slow brain activity, even though the bodies are frozen and dessicated. Any idea how that might be possible, Abaquq?”

“Impossible to say without further study, but these creatures might be capable of desiccating themselves and remaining in a state of very low activity for hundreds, possibly thousands of years. A few Earth-based species of worms are capable of such feats. Last year, they apparently managed to get a twenty thousand year old Siberian worm to come back to life. Okay, ground team. Tag the coffins for study, and potential retrieval. We might be in front of what’s left of the Hidden Steel civilization.”

“Do you see anything else?”

Qing tapped Serena’s shoulder, drawing her attention towards the carvings inscribed on the dome’s walls. They gleamed under the yellow lights emitted by bioluminescent bacteria.

“Alright, we have carvings. Ornamental, maybe ritualistic, they look too broad to be utilitarian. They’re alignments of dots, with…Abaquq, could you send me a view of the sky from your current location? Upload it to our shared HUD.”

Serena started walking around the room, as a high definition view of the starry sky appeared on her HUD, superimposed upon the rest of the world.

“One of the carvings is clearly a representation of the present-day night sky, save a few hundred, maybe a thousand years. All major stars are here, just slightly misaligned. Though the medium is quite primitive, the accuracy of the star map is remarkable.”

“Abaquq here. Is the other carving a map, too?”

“I think, yes. But it’s not accurate. I can only identify a few major stars, and they are all consistently offset to the right. This map may be older, and it would correspond to the natural relative motion of the Milky Way over several millennia. However, there seems to be more stars. About…I don’t know, five, ten percent more? And all the additional stars are highlighted with symbols. These stars can’t possibly have just disappeared, can they?”

There was a long silence, then Qing chimed in.

“It’s the Burn.”

She paused again.

“Fifty thousand years ago, there was one last war between the Forgotten Travellers and what remained of the Sequence. When it became clear that the cubic lifeforms could not fight the Sequence back anymore, they opted for a scorched Earth strategy. The Sequence moved slowly, under twenty percent of the speed of light, and they needed hospitable systems to set up bridgeheads in the galactic bulge as they led millennia-long offensives. The Forgotten Travellers decided to deny them these systems. They used relativistic kill vehicles and Dyson-Nicoll beams to destroy every single star system occupied by the Sequence. Out of all the visible stars in this sky, yes, that’s seven percent. Five to six million stars. The Burn.”

Serena took a minute to ponder Qing’s words.

“I think I get it. Imagine you are a space age civilisation, and you suddenly realise that the stars are just…going out. You are seeing the casualties of a war that started thousands of years ago, but you have no way of knowing it. You just understand that there’s something, out there, that’s devouring the stars. At first, just a few of them. Then hundreds. Then thousands. Then hundreds of thousands. Then millions. And it’s closing in. The sky has now become hostile. You do not have the technological level to flee, or even to understand the threat. So you build guns, and you put them towards the sky, for when the devourers comes knocking. It’s…derisory, of course. You can’t shoot down an interstellar relativistic kill vehicle with a Casaba. But this is all you have. This is all you can give to the sky.”

“And so you wait,” added Qing, “you wait and the devourer never comes, because it already died millenia ago. And while your civilisation is choking itself, you still stand guard. And in the end, that’s all you’ve got left. Fear of the sky. Forever.”

*

The Abaquq had positioned itself in a low orbit around the icy moon. Navigator Lazward had sent a messenger probe towards the nearest waystation to relay their findings. The automated vessel darted in the dark, fission drive at full thrust as it slowly matched velocity with its target destination, two thousand lightyears away. Soon, it would disappear in the night, leaving the Abaquq alone. Xiaomai Qing and Serena Shanxi rested in the observation bay, floating in zero-g. They had received preventive treatment for their radiation exposure, and the new muscle memories in their monads had been copied and uploaded. The mission was over. Serena raised her eyes from her book.

“Does Lazward plan to do anything with the coffins?”

“I don’t know,” answered Qing, half-asleep, “they contain remains of biological creatures that might still be alive in some way. Legally, we can’t move them without a Solar Envoy.”

“Do you think we may be able to revive these individuals?”

“I’m no biologist, Serena.”

“But…if we could revive them, do you think we should?”

Qing paused. She pondered the icy moon, perhaps trying to get a glimpse of the structure at the south pole.

“What's your opinion?”

“When they entered their desiccated state, they were probably the last survivors of their civilization. They still feared the sky. And now, we’d wake them up? We, people coming from the stars they were so afraid of? We, telling them that their great devourer was just a petty conflict between two dying civilizations, on a scale where the Hidden Steel was nothing but a pebble? They entered their sleep surrounded by a battlestation turned towards the sky, weapons primed and ready. That’s the only thing they had left. Standing watch. And we’d introduce them to a world showing how absurd their entire endeavour was?”

Serena sighed, then added.

“Let them sleep. This is not a watch we should end. ”