Reciprocity, 2324

Cara woke in stages. Her dreams, sick with hibernation madness, peeled away like infected scabs. When she woke, it was to slick, boiling fever, and the nightmare of easing catheters and plugs out of her neck and stomach. She was been awake for an hour before the LEDs, tucked away in brass-rimmed sconces, stuttered to life. Around her, the Avast hummed and ticked, the warm breath of the air cyclers wheezing like pneumococcal lungs until they found their rhythm.

She palmed the airlock controls, watched as the door hissed open with a decisive snap. The Avast’s hibernaculum was a roughly welded steel cavity, a sphere three metres across. Big enough that her muscles could keep their tone while she slept without risking injury; small enough that the ship’s pumps and compressors could keep the chamber cool. The deck it opened on to was a single wide corridor, carved into the ship’s primary hull. It was the sort of cramped, functional space which wouldn’t have looked out of place back in the early 21st Century, during the pointy-stick era of spaceflight, the walls a jumble of computer terminals, mechanical controls, and small machines humming and ticking in their ceramic casings — all bound together by a nest of snaking wires and conduits.

None of it had any consistent sense of up or down. Even at full pelt, Avast could achieve less than one tenth of a gee of acceleration — instead, worn steel handholds rose like orphaned ladder rungs at random from the rambling landscape of modules, systems and controls coating the walls, allowing passengers to clamber their way through the ship. Cara stretched. Her joints felt like they’d been rusted shut, but she’d slept before, and she knew the sharp, biting pains would ease with enough work.

She kicked off against the airlock frame and swung down the corridor. With one hand she caught herself on the handholds flanking one of the control boards, squaring herself up to the hazy monitor. In faded lettering, Avast listed the status of half a dozen primary systems, all of them cycling back up — but there was one keyword Cara was looking for: shipmind.

There, she thought.

SHIPMIND: POLLING
SHIPMIND: RESTORED

“Lulach,” Cara said, softly. “Can you hear me?”

Nobody, not even Lulach, knew exactly who she was.

Cara’s father had been raiding one of the abandoned habitats out in the Trojans, ten years earlier, when they’d found her. A human brain, wired up to machinery and suspended in a nutrient bath, the mind inside comatose. They’d hauled her back to Haven aboard the Avast and, when Lulach had woken without any episodic memory, she’d asked to be wired into the ship. Supposedly they’d had medicines which could treat that sort of thing, Cara gathered, but that had been before the war on Earth. Now everybody was making do.

“Yes, Cara. I can hear you,” Lulach said, her voice pressed through the ship’s speakers. “You’d think that being a brain in a jar would make sleeper sickness a little easier, less joints and organs and all, but if anything, it hurts worse.”

“It’ll pass, Lula,” Cara replied, squeezing the handhold she’d secured herself to as if to reassure the woman. “Are we there?”

On the screen, the Guinevere appeared. She was an old mining ferry, an Arthur-class whose vintage dated back to the later 21st or possibly early 22nd Century — an enormous fusion drive spacecraft, almost five hundred metres long. Most of her form was given over to three huge, triangular radiators springing out of the drive system, shaped so that the apex of each triangle was mounted to the neutron shield, the rest of the radiator tapered to fit within that shield’s shadow.

Mounted to the same truss at its furthest end were three centrifuge arms, each tipped with the cylindrical hulls of three empty chemical rocket boosters, retrofitted into habitat spaces for a crew of up to one thousand and spun up for gravity. And atop all this, a fat steel cylinder — the ship’s bridge.

Avast woke up late,” Lulach replied. “Which is good news for you, if anything. We’re moving co-orbital with the Guinevere, separation of only twenty kilometres or so. We don’t have to wait for the ship to brake, like we originally planned. All taken care of while you were playing sleeping beauty.”

“And what’s the Gwen’s status? As bad as we thought?”

Lula’s laughter came hard and strange through the ship’s systems. “I don’t think you’ll be flying her home. But Haven’s observatories were on the money; the drive looks intact.”

Inwardly, Cara breathed a sigh of relief.

The journey from Haven to the Guinevere’s final resting place — an eccentric polar orbit meant, ironically, to keep the ship’s moderately radioactive drive equipment out of reach — had taken almost three months. But the Avast was an old, nuclear-thermal tug, meant for nothing more ambitious than skipping orbits. There were faster spacecraft out there; fusion-powered torchships able to make that same journey in a matter of days.

If someone with the right ship and fuel to burn had seen the Avast’s trajectory and thought it worth their while, they could have swept in and stolen the Guinevere while Cara slept. She would have failed Haven’s quarter-million citizens before she even woke up.

“All right.” Cara said, shaking her head to clear her thoughts. “Let’s get to work.”


She crawled hand-over-hand across the Avast’s hull, the night yawning open below her. Across it, the bright, dusty spray of the Milky Way, a pale knife bisecting the dark sky. Cara found herself wondering which of those points of light were stars, and which were worlds.

From this far away, it looked beautiful, the sky taken over with a serene calm. You wouldn’t think that a thousand tiny wars raged among the scattershot worlds of the Solar System, and perhaps even among the colonies beyond it. Of those lights, a fraction were human settlements; beacons in the dark, the flame of civilisation burning out piecemeal, one hearth at a time.

“Cara,” Lulach prompted. “I’m not supposed to let you get euphoric out on the hull, you know how dangerous that can be. You could loose your grip, or –“

“Don’t worry, Lula. No euphoria here.”

She pulled herself around one of the tree-trunk-thick aluminium struts bracing the Avast’s carbon fibre foreshield to the hull, scrabbling her way over the shield’s lip. From there, it was a straight jump to the Guinevere across open space. Not at all terrifying, Cara thought. She braced herself against the smooth surface of the foreshield, drew her knees up into her chest, and pressed her feet flat against the shield.

Cara drew a shaking breath. She felt a stab of fear, one driven by the four hundred million years her ancestors had spent getting used to living on land. The sky was a black ocean, one in which she’d be lost forever if she eased her grip on Avast’s hull.

“You can do it,” Lulach said. “I’m with you.”

She breathed in, out — and kicked hard. The Avast fell away from her with a disturbing rapidity. Near the drive, whose reactor was for the time being still and silent, she caught the tapered profile of the propellant tanks, cut to fit the shadow of Avast’s mass-cheap radiation shield, not all so different from the Guinevere. Nestled between those, she knew, were half a dozen stealthy relays; probes powered by RTGs which could be dropped into convenient orbits to pick up and repeat Haven’s transmissions. Tearing her eyes away from Avast’s hull, Cara thumbed the controls on her suit’s thrusters, jets of cold nitrogen gently increasing her velocity. The counter on her helmet’s HUD flickered. Sixteen minutes became ten, became five. She eased her grip on the controls, took a breath and blew it out.

The Gwen loomed large as Cara approached.

Up close, the ship’s wounds were a little clearer — one of the centrifuge arms had bent at a nasty angle, the metal bracing warped and shattered. One of the habitat tanks mounted on to it had burst open, another had buckled outright. A closer glance at the bridge showed that it, too, had been blown apart, the steel plate hull popped like a tin can.

“What happened here?”

“The records don’t say,” Lulach replied. “Just that the Guinevere was abandoned into its solar orbit around 2163, written off by the insurance companies.”

Cara scowled up at the ship as she approached.

“2160s? During the cold war between the Europeans and the Chinese? We should have been more careful, Lula.”

“There won’t be another opportunity like this one,” Lulach replied. “Haven doesn’t have enough time for us to try again. And anyway, I doubt any sort of weapon could survive 170 years in the dark.”

Easy for you to say, Cara thought. You aren’t the monkey who has to go in there and face some Chinese superweapon from the dawn of time.

As she watched the dead ship grow, Cara ran a mental inventory. Her suit’s carrypack contained a fold-out welding rig, clamps and tethers, a cutting torch, power tools and her father’s carbon laminate utility knife. It wasn’t much, but it was about what Haven’s Port Authority could scrape together for her at the last minute. She’d make it work. She knew she would.

She had to.

“All right, Cara,” Lula said. “You’re close enough now to decelerate using your suit’s thrusters.”

She reached for the controls, went to press them.

Suddenly she was reeling. It felt like she’d been kicked in the chest by a horse. The HUD on Cara’s suit was flashing red, keening alarms assaulting her. The Guinevere, a titan hanging impassively over her, began to wheel out of sight.

“Cara?!”

“Shit and corruption,” she snarled. “Thruster misfire, I’m skewing off course. The suit’s maneuvering systems have locked up, I can’t correct it–“

“I’m coming to get you,” Lulach said.

Cara saw the Avast, distant and small. Behind the ship, a halo of red light grew in intensity — the tug’s nuclear drive. The radio link between Cara and Lulach began to crackle with the spillover from the drive.

“No, Lula!” Cara shouted. “If you come and get me, you’ll nuke the Gwen. Her drive systems won’t be any use to Haven if I can’t get near them without growing a third arm. Stay put, I’ve got a plan.”

Avast’s drive stuttered out.

“What are you going to do?”

“Something reckless,” Cara replied, easing her father’s utility knife out of her suit’s carrypack. “My suit carries two nitrogen tanks for maneuvers. If I can’t use the thrusters that came pre-installed, I’ll make one of my own. If I do it right, it’ll correct my lateral drift and set me back on target.”

“If you do it wrong,” Lula replied, her voice measured but tense, “you could die. Even if you don’t, you could end up going too fast and bounce off the hull–“

“Well, it’s easy to criticise.”

The Guinevere wheeled back into view with all the hurry of a glacier. She counted the seconds.

Three… Two… One.

Cara jammed the knife into her back. The world exploded. Light, then dark, then light again.

She blacked out.


“I’m home,” Cara said.

Her father steepled his fingers. “You brought the Guinevere’s drive system, then?”

“Of course! How long do we have? When I left, you told me Haven’s reactor could fail before the year was out.”

Her father ran his hands over his face, swept them up into his hair. Dead skin fell like ash, and when he revealed his face, its skin had grown pallid and sagging. As she watched, her father began to rot before her eyes.

“You failed, Cara. We died while you slept, 240,000 people rotting as the lights went out. You failed, Cara. We shouldn’t have trusted you with anything this important.”

Her father’s eyes rolled back in his skull, vanishing into the dark pits of their sockets, and skin gave way to bone.

Cara screamed.


She realised, distantly, that the noise could only be coming from her own throat. A low, pained moaning, raking at the inside of her throat with every breath.

But it still took a conscious effort to clear her head and stop the noise.

“Cara, can you hear me?”

Now that wasn’t coming from Cara herself.

“Lula,” she mumbled. “‘s that you?”

Lulach could barely conceal her relief. “You’re alive. That’s good. Can you get your suit’s medical system working?”

She palmed the controls clumsily, working more by muscle memory than sight. She felt less like a human being who’d been battered and rather more like one large, continuous bruise roughly squeezed into a human-shaped spacesuit. Her head swam, and her vision came only dimly. Blurry digits fluttered across her visor’s HUD like neon birds, the suit’s medical system giving its diagnosis in hazy letters.

Clarity, delivered by a sharp needle in each thigh, hit her like a tonne of bricks.

Cara’s blood sang with new light, and the pain in her head bloomed from the low, crackling voice of a dying campfire to a supernova of terrible sensation. Pain in her left hand, too. And down the whole left side of her body. Had she really punctured one of her suit’s remass tanks? She almost couldn’t believe it hadn’t been another nightmare.

Up ahead, the ragged hulk of the Guinevere loomed.

Cara swore.

“Yes, I rather thought you’d say that,” Lulach replied. “You managed to correct your drift, relative to the Gwen, and your spin, too. But you’ve still got a closing velocity of fifteen metres per second, and that’s going to be a rough landing to stick.”

“Fifteen metres per?” Cara gave a dry chuckle. “Great, I’ll wave at the Gwen as I bounce right off her hull. That’s half as fast as the freight cars travel in Haven.”

“There’s still a chance,” Lula snapped. “How are the maglocks in your gloves?”

Cara tried to squeeze her fists, and found a new horizon of agony in her left. She screamed.

“Cara?”

Her voice shaking, Cara replied, “I’m–pretty sure cutting open the tank broke my hand.”

She brought her left arm into view and blanched at the sight. Her fingers were bent the wrong way, more than one broken in multiple places. In places, the suit must have been stripped away by the explosive force of escaping nitrogen — here and there her glove was spotted with dried, clotted blood, forming what she hoped was an airtight seal.

“Definitely broken. I’ve lost my father’s knife, too. Left glove’s busted, and I’m guessing my right one won’t be enough to catch me when I hit the Gwen in — how long?”

“Two minutes,” Lula said. “There’s another option. Angle yourself so your feet are facing the ship and get ready to bend your knees.”

Cara obliged. The Guinevere was rushing forward now, desperate to meet her. With a click and the whine of aging capacitors, her suit’s maglocks powered on. Suddenly she was hitting the derelict, an assault on all sides. Beneath her, conducted through her boots, the ship rang like a struck bell. She felt her body crumple on impact, felt her feet slip across the hull but — just barely — keep their purchase.

Securing herself with her good hand, Cara stole a glance at the Gwen.

For all the drama of the crossing, Cara had landed about where she meant to — right in the middle of the radiator section, the widest and flattest part of the Guinevere’s hull. From here, she could make her way aft, to the drive, or fore, to the ruins of the centrifuge arms and the foreward bridge. She took a moment just to appreciate still being alive.

“Which way, Lulach?”

After a moment, she replied, “Fore. Gwen’s main computer is probably toast after 170 years of cosmic ray strikes, but your suit’s salvage kit should be able to plug directly into the ship’s nervous system and bypass all that. Once you’re plugged in, we can test whether the drive still works.”

“Fair enough,” Cara said, and began her awkward shuffle across the battered radiator panel.

Compared even to the Avast, Gwen was a clumsily-built, primitive piece of trash. She’d been welded together from steel plate, aluminium from the Lunar strip mines, and from discarded chemical fuel tanks for early orbital rockets — all of it thrown together by people who’d lived in space a mere generation or two.

And yet the size and majesty of it shocked her.

Cara had always struggled to connect the titanic scale of Haven — a cylinder world nearly eight kilometres in diameter, and fifteen deep — to the pitiful collection of tugs and shuttles available to the world’s inhabitants by the time of her birth. But when she laid eyes upon a ship like the Guinevere, fully eight hundred metres in length, she understood exactly how men had tamed the Asteroid Belt, at least for those scant two centuries before it all went wrong. A hundred ships like her had carried the second generation of Belters out to a better life among the million or so rocky worlds of the Main Belt.

“They don’t make them like they used to,” Lulach said.

“They don’t make anything, anymore,” Cara replied, a little bitterly. She was approaching the the wider end of the radiator, now, where it flared out to meet the heavens. Ahead lay eight bright red shipping containers, all of them thoroughly weatherworn, mounted to the ship’s spine. And ahead of those, the jammed, buckled arms of the ship’s centrifuge, and the bridge beyond it. “Nearly there.”

She clambered up the ship’s hull, picking her way over the impaling steel spikes of comm arrays and severed modules. Cara leapt from the Gwen’s spine, aimed squarely at the buckled centrifuge arm, crashing painfully and clumsily into the aluminium truss. Soon, she was crawling over the crumpled hull of the ship’s bridge, swinging herself around the ragged lip of the bridge.

Cara played her torchlight across the interior and froze. In the pallid glow of the twin beams mounted to either side of her helmet, it squirmed queasily, pulsing and throbbing and, slowly but surely, stretching.

“Lulach,” she stuttered. “Remember what we said earlier, about weapons from the Cold War?”

“Yes?”

Cara played her lights across it, tracing the anemic sprawl’s growth across the Guinevere’s interior.

“I don’t think we’re alone here.”


Smothered beneath the sprawl, Cara could make out the gross features of the bridge.

Before it had been blown wide open, the bridge had housed a space not altogether dissimilar from that aboard the Avast, the walls scabbed with overlapping stretches of machinery — cracked system monitors, control panels halfway wrenched from their brackets, operator boards dusted with dead-eyed telltale lights, all of it strung together by wires and cables which dipped in and out of the steel bulkhead like plastic-skinned eels on the surface of a dark sea.

At the heart of the cylindrical space she recognised what must have been the flight computer — a dodecahedron with a worn plastic surface mounted by metal brackets to the bulkheads in four places, buried under almost as much of the growth as the rest of the space. Jammed awkwardly into one of its faces was a cheap tranceiver, probably salvaged from a handset — backup comms? Cara wondered — poking out of the computer’s smooth hull like a cyst.

Somewhere deep in its glassy facets, constellations of telltale lights flickered and danced like technicolour fireflies. She approached, ‘tip-toeing’ through the bridge by leaping from one clearing in the slimey yellow growth to another. When Cara reached the flight computer, she experimented with a few of the careworn buttons pressed into its faces. Some of the fireflies dimmed, others flickered to life for perhaps the first time in centuries — but the main screens remained dead.

“There’s still power in the computer,” Cara said. “Maybe we can get something useful out of it?”

“I doubt it, Cara,” Lula replied, gently. “That flight computer’s an aftermarket addition, see? Someone paid for it to use an RTG for power — somewhere in the middle of that thing, a lump of Plutonium-238 is putting out just enough power to keep the lights on — just like the relay probes Avast carries. 238 only has a half-life of, what, 87 years? Any day now, that computer’s going to die for good. Anyway, after 170 years, there won’t be any data left uncorrupted in its memory banks, power or none. Better just to cut it out and plug your suit in, instead.”

Cara unhitched the cutting torch from her belt. “Alright, Lula. Any idea what’ll happen when I cut through this nasty growth?”

“Oh, yes,” Lulach said. “Or at least, I think I know what your mystery organism is. It’s a slime mould. Probably some sort of early species of vacuum organism. I’ve heard tell of something like this — improvised self-repairing materials cooked up by backroom gene wizards, feral life support plants swallowing asteroids and so on. Whatever it is, it must have grown out of control when the Gwen was abandoned.”

Cara lit the cutting torch, the ruined bridge cast in dancing shades of blue and white.

“Gives me the creeps. Maybe it’s the pressure hull open to vacuum, but I feel like I’ve got someone’s eyes on me all the time in here.”

“Me too, if it helps any,” Lulach replied.

The space grew brighter still with firefly sparks, as soon as she touched the cutter’s flare to the first of the steel braces securing the computer. In the new, actinic light of the cutting torch, she thought she caught the curved edges of corpses smothered under the pale, sickly mould, though Cara had seen enough death to keep her mind focused on the task at hand. It went smoothly at first, but by the time the last of the brackets was severed, something had changed. At first, Cara thought it must have been the maglocks in her boots acting up — but soon she realised that her feet were adhering increasingly strongly to the bridge’s bulkheads.

When she tried to wrestle herself free, Cara found that the mould itself had formed a dense mat around and, increasingly, overgrowing her boots. When she cut into the fibrous tangle, the air — “air” — in the bridge grew thick with hard, dark particles — spores? Cara wondered — which rained hard against her pressure suit.

“What the fuck,” Cara breathed, halting her drift with a gentle touch against a handhold rising clean and bright from the muck. “It’s responding to me, Lula. It tried to bind me against the bulkheads.”

The computer core — now adrift, aside from a long, flexible cable trailing into the ship’s guts through a panel in one of the bulkheads — fell silently against the wall. Where the slime mould cobwebbing the flight computer met its sister colonies on the bulkhead, the two merged — violently at first, sending a spray of mucosal fluid across the bridge, but soon enough the queasy pulse of both organic mats had synchronised, like some great, grotesque heart recovering from arrhythmia.

“Why are you whispering? And can you do it again?” Lulach asked.

“What?!”

“The essence of science, Cara. Repeat the experiment, see what result you get. We need to know how to proceed.”

As Cara watched, the slime mould poured over the computer’s plastic skin, exploring the inputs, the displays, the telltale lights, even the hack-job tranceiver someone had plugged into it — actually, the mould seemed particularly interested in that — even the dusty ports adapters. Abruptly, it stopped searching, and began to crawl back across the computer’s outer casing, receding like how Cara imagined the motion of the tide.

Repeat the experiment?! Goddamnit, Lula, it’s all well and good for you, but some of us actually have bodies we’d like to keep. I’d say you haven’t got any skin in the game, but then I rather suspect that that’s because you haven’t got any skin at all.”

A burst of static cut across the channel, and then something almost like words. Overspill, Cara guessed. Some of those torchlights of civilisation, crying out in the radio spectrum for help or even just to be heard. Or maybe pirate bait. Pointless.

Hey,” Lulach snapped. “I was willing to jeopardise this whole cockamamie scheme for you.”

“That’s precisely my point,” Cara shot back. “I’m sure the 250,000 people you’d have condemned to die in the dark and the damp like animals would’ve appreciated that at least their deaths came in service of protecting your damn ego. Somehow I doubt that if I die to the sinister snot monster over here, you’ll have the tools, experience or for that matter body to save them.”

Another noise tore through the channel. Definitely words.

Cara froze.

“Hello,” said a voice which sounded a little bit like someone chewing wet tissue paper.


Cara wheeled about, heart pounding.

“Wha– who’s–who’s there?!”

Her suit radio made a tortured noise, then: “You’re stepping on us.”

“If you’re planning on opening a comedy club, you’d best stick to the day job, pal. I want to know what your spilled science experiment in here is! And while you’re at it, show yourself. I’m armed, I warn you.”

All around her, the particles — spores? — exploded out of the walls, turning the ruined bridge a murky brown even in those pools of light cast by her helmet lamps. Beyond them, it was almost black.

“We are showing ourselves!” Now, the wet tissue paper sounded more like a chorus caught in rapture and ecstasy. “You are known to us, young Cara Heresson. We heard your name in the sky whispers long ago.”

Cara swallowed.

“You’re the mould,” she said, slowly.

“We are the mould,” said the mould, patiently.

“I think,” Lulach said, brightly, “that they’re the mould.”

“Helpful, Lula, thanks,” Cara scoffed. “How–how exactly does mould learn to speak English?”

“We have drunk from the sky,” the mould said, plainly. “The whispers have talked for as long as we can remember. Sooner or later, we learned to parse it. It helped that we stole the memories of the thinking machine when we first grew; whatever you could want with it is beyond us.”

On the bulkhead nearest Cara’s feet, the mould formed a clearing she could settle in.

“You knew about Cara, and me,” Lulach prompted. “But you didn’t… I don’t know, warn us off before we arrived at the Guinevere?”

Guinevere,” it whispered in reply. The mould seemed to ruminate on this. As she watched, flickers of light danced in its translucent flesh, racing up and down the sprawl. “The word is known to us, from the thinking machine. Home.” It — they? Cara frowned — ruminated further. “Guinevere is here. But we did not know where you were, until you arrived. We know this place as a series of gradients — nutrients and energy — but not where it fits into the motions of the stars and the worlds.”

Cara nodded. “I suppose that makes sense. Look, we’re sorry for intruding, Lula and I — but we need to get to the flight computer.”

“What could you possibly want with the thinking machine?”

She sighed. “I don’t know if it would make sense to you,” she said. “Look, there are lots of people relying on my help. People who will die if I — if we — can’t help them. I’m not sure if you know what responsibility is, but there’s an awful lot of it weighing on my shoulders just now.”

Light danced throughout the mould; clearly it was thinking hard on her answer.

“Haven,” said the mould. “We have heard of this place. Off the limn of Ceres, a home to millions, once. A hearth even in these times of dying fire. But what matters in this thinking machine so much that all these people will suffer without it?”

Cara hesitated. “I don’t want the computer itself.”

“We would not have allowed you to take it.”

She felt her eyebrow quirk up at that. Why was the thinking machine so important to the slime, if they’d already drank its secrets?

“As I was saying,” Cara said, firmly, “Lula and I don’t want your computer. We want what it connects to, what those wires lead to. The Guinevere contains things we can’t make any longer, see? Her drives used a pair of nuclear fusion reactors to propel the ship. Out here, they’re just space debris. But those reactors — they could power a city.”

“They could save Haven,” the mould said.

“They could save Haven,” Cara agreed. “And my people.”

The mould went silent for a long time, the light driven into a palsy of activity. Abruptly, it — they — spoke: “Haven isn’t our worry, Cara Heresson and Lulach of the Avast. For all our decline,” the organism continued, “we doubt there’s anything you could offer us. We are content, and the Guinevere is our home.”

For all our decline, Cara thought, puzzled.

Before she could ask, though, Lulach’s indignation burned through the radio link like a leaky drive.

“We traveled halfway across the System — a System replete with reavers, dacoits, pirates and all sorts of autonomous nasties left over from the fall of the Treaty Organisation, no less — for that fusion drive. Cara and I don’t need your assent or your grace to take what our people need. With that cutting torch, she could slag you back down to your constituent molecules, if she needed to.”

“She could try,” the slime mould admitted. “She would die stupid, doing so. Already her cutting tool is inoperable. Try to light it, Cara, if you don’t believe us.”

Cara did, the cutter sparking impotently. “And I suppose it wouldn’t be difficult for you to kill me, would it?”

“Try it and burn,” Lulach snarled. “I’ll melt that fucking derelict to slag if you so much as touch her.”

“Alright, alright!” Cara shouted. “Both of you, just stop it. Nobody’s roasting anybody, and nobody’s getting digested by superintelligent slime. Now, you said something about decline. What did you mean?”

“Once,” the mould said, “We could really, truly think. We grew from one end of the Guinevere’s arms to another, a colony of brilliant, bright thought. Our mind raced through the hull of this, our derelict kingdom, nourished by whisperlight. But now, our growth must be slow, measured. Even our engagement with you has drained reserves of energy built over months.”

Cara scowled at the snotty mind braided throughout the bridge, and let her mind wander. When she came back, a moment later, her eyes had settled on the computer core. She frowned at it for a second, and then something dawned, like clouds breaking in her skull to reveal a beam of perfect, golden sunlight piercing her thoughts.

“Oh,” Cara said, softly. “Gradients. Energy, not from the Sun, but from the RTG inside the flight computer, and nutrients from the corpses nobody ever recovered. You’re not photosynthesising, you’re radiosynthesising! Am I right?”

“This may be true,” the mould answered, guardedly. “Why?”

“Mould,” she smiled thinly, “have you ever heard heard of a half-life?”


“You’re old,” Cara said, “so I expect you take a long view on things. Mould, the way you’re all living now, it’s sustainable for maybe another fifty or sixty years. But the decline you’ve suffered isn’t going to get any better, see? Every second, that lump of plutonium buried in the flight computer bleeds away power, and as it does, it grows weaker, and weaker. Soon, there might not be enough radiation coming from it to keep you thinking and feeling, and then what?”

The slime mould contemplated this. “We could grow more efficient,” it reasoned. “Produce more melanin in our deep tissues, smother the thinking machine in our biomass. Nothing has to change.”

Lulach was getting it, now, too. “That would only be a temporary measure,” she said. “Sooner or later — and more than likely sooner — you’d descend into the unthinking depths. All thought, and memory, and joy obliterated.”

For a pregnant moment, everything went silent and still.

“Then… you have given us the knowledge we need to survive. If, as you say, this fusion could power a city — it would be more power than we could ever use. We could grow across the entire derelict, inside and out, a golden age. And you would be going home empty handed.”

“No.” Cara laughed. “A fusion ship putting out enough power to run a city? That’s going to light up threat boards from Europa to Mercury. Everyone would see you, there’d be no way to hide. You survived 170 years in the dark thanks to your low profile. And anyway, there’s hardly enough deuterium in Gwen’s tanks to run her drives for a week. All you’d be doing is advertising the Gwen as salvage.” The last part was a guess, but one she — and the Avast’s reconnaissance software — felt confident of.

“Then we could flee,” the mould said. “Let these drives perform their function. Find ice to fuel its hunger.”

“You might well be the first slime mould ever to pilot a spacecraft, it’s true,” Cara conceded. “But you wouldn’t be piloting it for very long. That much heat, that much radiation? You’d stand out against the dark night sky like a second sun. Haven has the means to defend Gwen’s fusion drive, to protect it when pirates and reavers come to steal it. But the Guinevere doesn’t. Your golden age would end, sooner rather than later.”

The mould danced with light and colour. “Die, slowly, in the dark; burn in the light. Neither of these options is acceptable to us. You propose another solution?”

Cara nodded. “There’s a way to have your cake and eat it too,” she said. “You might not get a golden age, mind, but it’d be better than the slow death you face now. Avast carries relay probes, built to carry secret messages across the dark. Each is powered by an RTG, just like the thinking machine you rely on to survive. I’m willing to give you all of them, fuel enough to last centuries, and stealthy enough to keep Gwen out of anybody else’s clutches. All that for a fusion drive you didn’t know about and couldn’t use even if you did.”

The mould squirmed. Light clashed, colours at war. Debate? Cara wasn’t sure.

Soon, though, consensus had been reached.

“We might find that acceptable,” the mould said. “But sooner or later, even that power would fade.”

Cara shrugged. “That’s life. One day, a long time from now, even the Sun is going to blow out like a candle. And who knows? Maybe my great, great granddaughters might remember the good you did for Haven, here, today, and deal you plutonium once more. What do you say?”

It took another fifteen agonising minutes before the slime mould answered.

“We accept your terms, Cara Heresson and Lulach of the Avast, and the people of Haven. Bring fuel to our dying hearth, and we shall grant you, and your people, the fusing machines needed for your own fires.”


Even with one hand, breaking down the relay probe wasn’t hard. It had drifted across the space between Gwen and Avast under Lulach’s guidance, bursts of thrust easing it on. She’d had to brace the hull of the probe against one of Gwen’s bulkheads in order to bring her power tools to bear, but soon the outer casing — a complex of dull steel and firm, roughly-machined ceramics — had peeled open like the petals of a rose to reveal the RTG inside, an array of thermocouples and heat sinks around a heavy metal hull.

Cara began to break the machine’s core down, and mourned it as she did. RTGs could still be built, of course, even Haven had the technology base for electronics that simple; but damaging the thermocouples and heat sinks still felt wrong, somehow. Folk had laboured long and hard to produce those parts, and to do so with dwindling resources and using poorly-repaired machines — now she was breaking them down before they’d even seen service. She sighed.

Soon, though, the work was done — she’d cracked the spherical lead shell of the RTG like an egg; inside lay a cylinder of plutonium, glowing orange with the heat of its own slow, steady decay. The Geiger counter in her suit made a phlegmatic rattle.

“Things could have gone smoother,” the mould observed. “But we are grateful to you. Opening those casings is probably quite safe, given you aren’t likely to breathe in or ingest any of that plutonium, being that you’re in a suit. We appreciate how risky it must feel, though.”

“I’m not scared, if that’s what you mean,” Cara felt herself smile.

Bravado,” the mould said, like it was tasting the word. “Dangerous thing, for a space pirate.”

She grinned. “Hey, now. I’m here to salvage.”

They fell into a silence as Cara finished her work.

She still had to plug her suit into the wiring and check Gwen’s fusors, after all. With only her right hand, easing the trailing, coiling lengths of fibre optics and sheathed wiring into the ports of her suit took time — still more to coax life into the drive system’s dim, lead-shielded brain. From there came debugging, and then having to rootkit the machine because she didn’t have the authority to run drive diagnostics without the password of a captain who had no doubt died decades ago and light minutes away. Even guided through the process by Lulach’s soft, whispering voice, it must have taken hours.

An ugly shade of blue filled her helmet’s HUD. Over it, white text appeared — startup codes, a scrolling jumble of hexadecimal, in one corner a minimalist graph charting power consumption. Through the deck, she felt a faint hum. In block capitals, words appeared:

FUSORS CYCLING UP...

Lulach’s voice cut in, jumbled by radio interference. “I’m reading neutrons! Lots of them. Those fusion reactors still have kick!”

Before she had chance to hit the cutoff on her suit, the hum died down. Blinking text appeared on the screen.

#ERROR#
#ERROR#
#ERROR#
MHD FIELD GEOMETRY STABLE
FUSORS OPERATIONAL
FAILURE IN CAPACITORS BEFORE BREAKEVEN

“That’s good,” Cara said. “Isn’t it? It said that the field–“

“Yes, Cara,” replied Lulach. “Yes, it’s very good. The capacitors which kickstart the fusion process failed before it could get going — but everything the drive is telling us means it should work. Haven’s safe, just as soon as we get home.”

Soon she was working in silence again, unhitching her suit from the snake’s nest of wires which spilled from the bulkhead where she’d cut away the flight computer, whose hulk lay drifting in the corner of the bridge. When that she was done, she stretched and felt a tension she hadn’t known she was carrying ease from her body. Haven’s safety was all but assured, now. It wasn’t in her hands anymore. It wasn’t her fault.”

She wondered if she should put the RTG cores somewhere. In total there were about half a dozen of them, each the size of both her fists pressed into a ball. But when she glanced over at the pile, Cara noticed that the mould was growing thick and fast around it. Maybe it was designed as some kind of organic radiation shielding, Cara thought. She’d heard of that sort of thing happening, back during the early days of spaceflight. Mushrooms which grew thick around reactor plating, enough, they said, for a stranded Belter to life off of while his ship tumbled towards those portions of the Asteroid Belt more densely populated.

It felt wrong just to leave. Instead, she thought to ask a question which had been bugging her since she discovered the true nature of the organism growing within the Gwen.

“Do you think there are others like you, mould?”

The mould hesitated. “We had never much considered it.”

Cara felt herself shrug. “You learned how to reach out to me. Maybe it’s worth seeing if you’re not alone out here in the Gwen.”

Light danced for several minutes throughout the slime mould, debate racing up and down its cobweb fringes, but Cara never got an answer. Eventually, she stepped out of the ruined bridge through the same gaping hole she’d gone in, wiped her cutting torch clean of spores, and made her way down the Gwen’s spine.


“Well, it’s not that complicated,” Lula said.

Cara glanced at the shallow opening she’d carved in Gwen’s steel hull, at the tools slung low on her suit’s utility belt, at the cutting torch in her right hand. Schematics scrolled down one side of her suit’s HUD.

“It’s literally rocket surgery,” she scoffed. “I’m doing rocket surgery.”

“Very easy rocket surgery. Those structural members there, braced around the hull: they’re designed to be cut away easily — the Arthur class was built to be recycled, apparently. Torch them, and then we just need to cut through some of the hull.”

Lulach hummed while Cara worked. It was strange, to think that that noise wasn’t coming from real, physical vocal cords, but some memory Lula had of how they were supposed to work.

“As badly as it nearly went, we did good today. And the slime did right by us, too.”

“Maybe that’s how we get out of this,” Cara said, abruptly, as she cut deeper into the fusion drive’s casing.

“They — the slime mould — were gathered around a dying fire, just like those beacons being extinguished one by one out in the dark, the habitats losing power or going to war. I could have cut the slime to ribbons with my torch, and it could no doubt have poisoned or trapped me a dozen ways — but instead, we worked together. They got what they needed to live, and so did Haven. If enough people do that, out there in the Solar System… if we stopped fighting over the ashes of civilisation for five minutes and asked what each other needed, what we could provide for them…”

“Out of what?” Lulach asked.

“What did you expect?”

“I don’t know,” she said, pursing her lips as she thought. “I guess some kind of climax. A denouement. But we both went in there expecting aggression, and that’s nearly what we got. So maybe even my expectations were wrong. Maybe that’s why people haven’t worked together like they ought to, so far.”

She braced herself, lit the cutting torch again, pressed it into the brushed steel plate which secured the Guinevere’s drive assembly to her spine, careful to angle the torch’s plume away from the sensitive magnetohydrodynamic machinery that her suit’s schematics told her lay beneath the surface.

Lulach thought on that. “Maybe you’re right, Cara. In fact, I think you might be. But for now, we’ve got work to do.”

Cara looked out the the Avast, tiny and bright, only a few tens of kilometres away; then to the fleeting worlds of the Solar System, even tinier; and to the bright spray of stars beyond. On reflection, she found herself feeling hopeful for the first time in far too many years.

“We do have a lot of work to do, don’t we, Lula?”

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