THE DESCENT A Tethys Consolidated penal contract Logline An ocean planet has one wound in its seafloor, and something at the bottom of it is sending a signal. Machines stop working down there and free crews don't come back, so Tethys sends a convict instead: a lifer rebuilt as half a machine, with a carrier, a few robots and a ship's AI that answers to the company. His sentence ends at the bottom. Hadra Hadra orbits a dim red dwarf 31 light-years from Earth. It is slightly smaller than Earth and has no land at all. A single ocean covers the whole planet under a permanent overcast. The only feature anyone has charted is the Throat, a vertical fissure 400 m wide in the seafloor. Under the seafloor the crust is honeycombed with voids full of warm, fresh water, some the size of a room and some the size of a city. Hadra's centre should be dense, hot and solid. Every reading says it is not. The Signal In 2193 a survey probe went down the Throat and fired one deep sonar pulse straight down. The return came back 28 minutes later, from close to the centre of the planet, and it was louder than the pulse that went down. An hour later the probe stopped transmitting. The return never stopped. The buoys on the surface have heard it ever since: one deep, slow pulse from the centre of Hadra every eleven minutes. Nobody has sent anything to cause it. It has a structure nobody has decoded. The official survey lists its source as "the Floor, depth unknown". Tethys wants two answers: what is sending it, and what it is made of. Tethys Consolidated Tethys holds the only licence to Hadra from the Colonial Registry. Its only presence on the planet is Anchorage, a floating platform above the Throat, where a small research team listens to the signal. None of them has been down. Tethys sent drones first. Below the Seam they stopped answering. They were not crushed and they did not crash. They kept running and stopped doing what they were told. Then it sent people: nine contractors on the carrier ANTIPHON. Their last log came from the Galleries. Free crews are expensive, and their families ask questions. The Commutation So Tethys found people nobody asks about. Under a Registry penal programme, a prisoner serving life, or waiting for execution, can sign a Descent Commutation: one descent in exchange for the sentence. The prisoner is converted before transport. The skeleton, the limbs and the heart are replaced, and the lungs are reinforced. The brain, the spine and the gut stay human, because a human mind is the only kind that has held up below the Seam. Then the convict spends nineteen years in cryo aboard a Tethys hauler and wakes up above the Throat. You You are one of them. Your file has a name, a number and a crime, and the crime is redacted. The conversion took some of your memory with it. You do not remember the trial. Your body needs four things. Charge. The machine half runs on power from the carrier. Food. The human half still eats. A port in your forearm plugs into the nutrient line in the carrier's wall, which draws from the biomass reserve. The reserve runs out, and the only way to refill it is to catch what lives in the voids. Air. You still breathe. In the water you breathe from a tank. Warmth. The cabin is held at 26 °C for the parts of you that are still human. Tethys also left you your fear. It is not a defect. It is part of why a human brain works down there. The Cradle Tethys does not lose a convict to one death. The carrier's cradle records your mind every time you sleep in it. If your body dies, the cradle wakes you from the last record, and you remember nothing after it. (In the game, death sends the player back to the last save. The cradle is the story's reason for it.) The Crew You are the only human aboard. Everyone else is a machine. WARDEN is the carrier's AI. It runs life support, the cradle and the robots, records everything you do and reports it to Tethys. You steer the carrier; WARDEN cannot, and it cannot be switched off. It is the only voice aboard besides yours. Its specification does not say whose side it is on. The robots do the heavy physical work: hauling ore boxes, feeding the refinery, patching the hull. Tethys ships a few, and you build the rest. A damaged robot can be repaired, and a destroyed one can be stripped for parts. The deeper the carrier goes, the less they do exactly what they are told. The Carrier The CANTICLE is a deep carrier built for a crew of one. It has quarters, the cradle, a bridge, a moon pool, a cargo bay and a refinery deck, and every section of it is modular and can be upgraded. It is too big for most of the Throat, so it goes where you open a way for it. In its bay it carries Tenders: small submarines, also modular, that you build and refit as you go. You take a Tender out through the moon pool, find a way with sonar or by swimming, drill through what blocks it, collect the ore and the fauna, and cut the passage wide enough for the carrier. Then you go back aboard and take the carrier through yourself. Ore and the Sentence Ore is refined on board into everything you need: hull sections, Tender frames, drill heads, robots, sensor modules. What you don't need you can send up to Anchorage. Tethys pays in two things: patterns your fabricator is allowed to build, and days off your sentence. Reaching the source of the signal ends the sentence outright. Nobody has collected yet. Wet Rock The water in the voids is warm, fresh and slightly conductive, and three things about it are wrong. The pressure is too low. Deep in the crust the water should crush any hull ever built, but in most voids the pressure is a fraction of what it should be, as if something were holding them open. Some voids carry the full pressure their depth predicts. A hull that breaks into one of these "honest" voids implodes. Sonar is the only way to tell an honest void from a safe one before you drill. The voids connect. They form routes that lead down. The logs of earlier convicts joke that the Throat wants to be descended. The Throat Moves Hadra has quakes. They come without warning, and they close the tunnels you cut, open new voids and shift whole galleries. No map of the Throat stays true for long, and no two descents are the same. The voids are full of life: lanternfish, jellies, glowing polyps, and bigger things further down. All of it is food. The Strata Name What's there The Throat Black basalt and silt. Wrecks of the survey probe and the drones. The last dim red light. The Honeycomb Porous rock and the first voids. Common metals. The first fish. The Seam The rock changes character. The instruments stop agreeing with each other, and the robots start making mistakes. The Galleries Kilometre-scale caverns where headlights don't reach the far walls. Something here glows. The ANTIPHON's last log came from here. The Ossuary Rock laminated in layers as regular as shell or bone. Exotic, valuable ore. Drill heads dull fast. The Quiet Sonar returns degrade. Sensors report movement nobody can confirm. The robots stop answering. The Floor Stratum Zero. Nothing cuts it. It is warm to the touch, and every eleven minutes it pulses. The signal comes from below it. The rock gets harder with every stratum. The fabricator has drill-head patterns for every stratum except the Floor. The Echo (dev-only truth) Hadra is not a planet with something living in it. Hadra is the living thing. The voids are its chambers and vessels, and the low pressure in them is it holding them open. The honest voids are the places it has let go. The quakes are it moving, and closing the wounds you cut. The fish, the jellies and the things below them live in its blood. The Ossuary is its tissue, grown in layers. The ore is not mineral. The Floor is its skin, and the pulse is its heartbeat. The signal is that heartbeat heard from outside. The ocean on the surface formed later, around it. In 2193 the return came back louder because the pulse was answered, and it has been answering ever since. Below the Seam, the signal gets into anything that thinks without a body. That is what happened to the drones, it is what starts happening to the robots, and in the end WARDEN hears it too. A human mind takes longer. It hears the signal as fear, then as voices, then as something that knows its name. Tethys knew before the first hauler left Earth. The ore that comes up goes to a buyer who is never named. Convicts are sent because a human mind lasts longer than a machine down there, and nobody comes looking for a convict. The cradle records your mind every time you sleep. Below the Seam, the records start to hold something that is not yours. What waits at the Floor is not decided yet. How It Reaches the Player The black box of the 2193 probe and the logs of the lost drones. Beacons left by earlier convicts, cut off mid-sentence. The ANTIPHON's carrier log. WARDEN's orders from Tethys, with lines redacted. Radio from the research team on Anchorage. Your own case file, and letters from Earth that are nineteen years out of date when they arrive. Robot work logs that don't match what you told them to do. The signal itself, on the sonar table, every eleven minutes. Moving the story off Earth also removes the physics problem: on an alien world, water voids and a hollow core only have to be mysterious, not impossible.