Titan

BOOK SIX Titan Summer

Voyager One reached the boundary of the Solar System.

This was the heliopause, the sheet in space where the wind of ionized particles from the sun grew so feeble it was overwhelmed by the broader stream of interstellar ions. Already Voyager was a hundred times Earth’s distance to the sun, ten times Saturn’s distance.

When gushes of solar plasma hit the heliopause, immense radio blasts — a hundred trillion watts — were generated. Voyager’s instruments, almost overwhelmed, recorded this, and faithfully attempted to download the data back to Earth.

Still there was no reply, no reassuring command stream.

Even beyond the heliopause, the sun’s gravity held sway; there were clouds of objects out here — ice moons, a trillion comets, never observed by humans — circling the central star. Voyager soared through this new realm, its radioisotope power slowly fading.

Voyager tried to contact Earth until its reaction gas failed, and it could no longer point its antenna. And by 2020 there was no longer sufficient power to drive the radio transmitter. Still the software cycled through its reacquisition algorithm, sending commands to inert attitude thrusters and radio transmitters, until the last trickle of power died.

It took twenty thousand years for Voyager to cross the Oort Cloud, the sun’s immense swarm of comets. At last it was free of the Solar System, its final gravitational bonds broken.

Its power and radio transmitter long dead, Voyager embarked on a new journey through the silent calm of interstellar space: an endless circling of the heart of the Milky Way galaxy.

There was almost nothing here to damage the derelict craft. The stars were so sparsely scattered that Voyager would never encounter another stellar system…

As time eroded, the logic of physics unfolded implacably. The sun was no longer young. Its core became denser and hotter, as it clogged with the accumulated helium ash of billions of years’ hydrogen fusion. The sun got brighter, at the rate of eight percent per billion years.

But for a long time Earth’s surface temperature remained the same. Earth was protected by matter and energy feedback cycles maintained by living and geological processes. And as the temperature rose silicate rocks weathered more easily, absorbing carbon dioxide from the atmosphere.

But it couldn’t last forever.

Eventually the carbon dioxide concentration in the atmosphere fell so low that the plants and trees could no longer photosynthesize. That put an end to the biosphere’s carbon supply. The rocks continued to weather, and the carbon dioxide concentration fell still more rapidly, and Earth heated quickly.

Maybe humans could have prevented this, with some huge feat of planetary engineering. There were no humans around to try.

On the parched planet, one species after another faced what human biologists had called thermal barriers to their survival. The more complex plant and animal species diminished first, as Earth shed the biological complexity painfully gained over billions of years.

After a billion and a half years the surface temperature averaged fifty degrees Centigrade, above which no animal, fish, crustacean or insect could survive. Most vascular plants and mosses succumbed as well, leaving the land and oceans empty save for micro-organisms: multi-celled animals like algae and fungi.

But above sixty or seventy degrees the structural characteristics of even the simplest multi-celled creatures — like membrane systems — could not be sustained. The survivors now were one-celled creatures, like cyanobacteria and some photosynthetic bacteria.

Above seventy degrees photosynthesis ceased at last.

The last survivor of Earth’s once-rich biosphere was a hardy bacterium, swimming through the sulphur-rich waters surrounding a black smoker ocean-floor vent. The story of life on Earth had come full circle, for the heat-loving archaebacteria were among the oldest life forms: they had arisen on a younger, hotter Earth, and become the progenitors of all subsequent life.

The end came at two hundred and fifty degrees Centigrade, above which the very stuff of life — the giant molecules, nucleic acids and ammo acids — was broken down.

After another hundred million years the oceans began to boil.

Huge clouds of vapor were suspended in the atmosphere. A new greenhouse factor came into play, driving temperatures higher still, ever faster.

The water clouds did not last long. The water vapor was broken up by energetic sunlight and its hydrogen was driven off into space, leaving a planet baked permanently free of water.

And the loss of all water stopped the weathering of silicate rock, the process which drew carbon dioxide out of the atmosphere. Volcanic carbon dioxide began to accumulate in the atmosphere. New clouds rose, and the planet began to bake…

At that remote time, Venus and Earth became at last what humans had dreamed in ancient times: twin planets, alike in every significant detail — scorched dry, their surfaces cracked and flattened under a dense, sluggish atmosphere, utterly lifeless.

It was different, for Titan.

The heating of the sun ruined the old surface of Titan, the gumbo-streaked, icy landscape humans had explored. The ethane of Clear Lake boiled, evaporated. The gases dissolved there — nitrogen, methane, hydrogen — thickened the atmosphere still further, adding to a greenhouse effect that accelerated the warming of the atmosphere.

Eventually the comparatively thin shells of ice over the magma — the ancient ammonia oceans — melted, exposing the primal seas once more. Ammonia and water vapor enriched the air and boosted the greenhouse effect still further.

It got warm.

The remnants of ancient biologies stirred. A story of life, interrupted billions of years earlier, was able to resume.

For a while. But it was a life which would not have long to flourish.

Soon, the sun neared the end of its stable Main Sequence lifetime; it began its final, deadly bloom.

When the sun’s core hydrogen was exhausted, the fusion fire there dimmed. For ten million years the core contracted. Then a shell of hydrogen outside the core started to burn. That started the expansion of the outer layers.

The sun grew gigantic, its surface billowing towards what was left of the inner planets. Confronted by the huge face of the sun, Earth’s surface temperature reached three thousand degrees, only a little less than the surface of the expanding sun.

Life on Titan shrivelled, baked, as even the water ice bedrock began to melt.

…Like a desiccated dragonfly corpse adrift on a breeze, Voyager One circled the heart of the Galaxy.

At last the slow sublimation of metal caused the aluminum structure to weaken to the point where its ten-sided framework collapsed. The fragments of the spacecraft — instrument booms and power generator, pitted and tarnished, metal walls reduced to a paper thickness — drifted away from each other. The directional antenna, as thin as a dried autumn leaf, crumbled away from the curving spars that supported it, so that the ruin of the spacecraft was surrounded by a cloud of glittering aluminum dust.

Voyager was a fragment of American technology, a thing of metal dug from the vanished Earth, some twenty thousand light years from the sun. It was the last human artifact in existence.

…Rosenberg was lying on his back.

His eyes were closed. He was warm, comfortable. He was aware of his body — his face, arms, legs were a tangible, solid, massy physical presence — but there was no EVA suit around him, no sleeping bag.

He seemed to be rising. As if he was in some huge elevator.

He opened his eyes.

He was in darkness. He could see only the fuzzy patterns, star-bursts and whorls, generated by the hard-wiring of his own nervous system.

He could hear nothing.

Maybe he was in some kind of sensory deprivation tank.

He tried to remember how he’d got here. He remembered Titan — the Cronos EVA, those damn carrots, Benacerraf nursing him back in Discovery…

I ought to be dead, he thought.

Was this some kind of hallucination? Was he still propped up in that lumpy Apollo couch in the hab module, wrapped in Beta-cloth, his senses failing as his body slowly fell apart?

He felt a stab of panic.

He reached up to his face. He felt his cheeks, the pressure of his hands, the bones of his nose.

His cheeks were smooth. Free of stubble. And when he ran his palms up over his face, there wasn’t a hair on his head: no eyebrows, no eyelashes.

He reached down to his groin. He was naked. His hands cupped his genitals, warm lumps of flesh. No pubic hair.

He jammed a finger up his left nostril. No hairs there, either.

Puzzling.

And, he thought, you’re moving pretty well for a guy in the last stages of Vitamin A poisoning, Rosenberg.

Anyhow, this was no hallucination. I can feel my balls, therefore I am.

He dropped his hands to his sides. His hands hit something. It was a soft, pliable floor of what felt like plastic. It seemed to have no temperature, neither hot nor cold.

He felt to left and right. The floor stretched under him. He could push his fingers an inch or so into the material before he reached the limits of pliability, where it became tough and hard.

Maybe he was in some kind of bubble.

He didn’t have enough data to work on. He ought to wait. Maybe he could sleep.

Sleep, right.

He tried to control his fear.

Be logical, Rosenberg. Whoever has brought you here, wherever here is, can’t mean you any harm.

He ought to separate the world into pieces he could understand. Dismiss the problems he could do nothing about.

Like, the air. Where was it coming from? How was it replenished? Was it poisoned?

Here’s my plan: don’t breathe, until we know more…

He had to accept the air. He had to accept the temperature, the living conditions.

Later, he would be hungry, thirsty. He would have to deal with those problems when he could.

Great logic. He found he’d cupped his hands over his genitals again. A primate reflex, he thought. I’m just a scared monkey, alone in the dark.

On impulse, he spoke. “Hey.”

He could hear his voice.

“Testing, one, two. How about that.” He clapped his hands. He heard no echo, just the dead sound of the clap itself. So, a little more data. This bubble, or rubber room, whatever, was anechoic…

Something changed.

There was a light above him, deep crimson, barely visible. The intensity varied as he moved his head from left to right.

Work it out, Rosenberg. That means the light is external to you. There’s something above, which is differentiated from what is below.

The light seemed to spread, as if across a flat surface. He thought he could see ripples, scattering oily highlights. Maybe he was rising up through some fluid, towards a meniscus.

He looked down at himself. He could see his body, emerging in the gathering light, chest and legs stretching away before him, his nipples dark against a hairless chest, a faint landscape of flesh.

He was bald, but healthy. No sign of the Vitamin A crap that had killed him.

…The light brightened. Suddenly he was approaching the surface. It was indeed a meniscus, the surface of some body of fluid, and he could see slow, fat ripples, streaks of some scummy deposit—

The surface broke, in a pulsing circle, directly above him. The fluid spilled down over the hull of his protective bubble.

He saw a sky. It was high and tall, and scattered with thin, ice-white cirrus clouds. There was a fat red sun — too big — near the zenith, bright enough to dazzle him, surrounded by a fine halo. Contrails criss-crossed the sky.

That sun really was too damn big, and the sky was a rich blue-green.

The fluid fell away. The chamber was dimly visible around him, like a soap bubble, in glimmerings of refracted light.

Rosenberg sat up.

All around him, beyond his bubble, a solid mass was breaking the liquid.

The surface was corrugated, and it glistened, deep green. And as it rose, he could see how the platform bulged upwards, a dome perhaps fifty yards across. His filmy bubble perched, squat, on the top of the corrugated dome, as if on the back of some immense turtle.

Rosenberg got to his knees. He pressed his face and hands flat against the warm surface of his bubble, and stared out.

The dome, still rising from the liquid, was an island in an oily sea that stretched to the horizon. The fluid wasn’t clear; it was overlaid by a purplish scum, frothing in places. There were a couple of pink-white ice floes, clustering amid the scum islands.

The air was clear, if green-tinged, and he could see thick, fat ripples proceeding in concentric circles away from the rising mass he rode. Further out there were waves — they looked gigantic, mounds of liquid maybe a hundred feet tall — and they drifted across the sea, driven by the prevailing winds.

He could see land.

Perhaps a mile from him, there was a shallow beach; and beyond that, a cliff, steep, grey-green and heavily eroded.

It could be Cronos, he thought.

He wanted to try something.

The bubble was too small to allow him to stand up, but by squatting on all fours he was able to thrust himself up into the air, by a foot or so.

It took him maybe a half-second to sink back to the floor.

He tried it a couple more times, before he was satisfied. The gravity here was low, surely no more than a seventh or eighth of a G.

Right. He was still on Titan. But a Titan that was changed, out of all recognition.

…And the sun was too big.

It was the central fact he didn’t want to face.

It was so big it outsized the fat yellow sun of Earth, let alone the shrunken disc he’d observed at Saturn. And it was a deep, angry red. He thought he could see spots, gigantic black flaws, sprawled across its disc.

He could only think of one way the sun could have gotten so big, so red.

By getting old.

Oh, shit, he thought. I am a long way from home.

It was all too big, too much. He was a scared, naked primate, stranded in an alien future… He could do a Bill Angel, retreat into some dark primitive recess he’d brought with him, all the way from the past…

The hell with that. Think, Rosenberg. Categorize.

He thought about the gravity. The waves.

All that proved the laws of physics were still working. And he could still figure things out. Even run experiments, test hypotheses. Hang onto that, Rosenberg. Whatever the hell is going on here, science still works. I can figure it out.

Anyhow, isn’t this what I wanted? To cheat death — to see how it all came out in the end?

…But, deep down, he had expected some kind of team from Earth to retrieve them, human faces peering over some kind of hospital bed.

Not this.

He wanted to curl into a ball, retreat into sleep and incomprehension. But if he did, he might never come back out.

His shadow, blurred by its passage through the bubble wall, fell over the corrugations, shortened by the high angle of sunlight.

He tried to feel the corrugations through the bubble material, but the stuff wasn’t flexible enough to give him any real sense of touch. He thought he could see something of a cellular structure, though: there was a crude graininess to the corrugations, lumps maybe the size of rice grains. Cells, maybe. The surface looked almost porous, where he could see it closely. There were beads of some liquid gathered there, and a crusty, solid deposit…

I bet that solid’s cyanogen. His mind raced. This is some kind of animal.

Ammonia life?

Come on, Rosenberg, you know the theory. His huge steed must drink ammonia, respire by burning methane in nitrogen. But cyanogen, the carbon dioxide analogue, was a solid at these temperatures. And so the hide of this creature was dripping with ammonia, and crusted with cyanogen waste.

In that case, he thought with growing excitement, he had to be rising out of an ammonia ocean, polluted with complex, melted hydrocarbons. There must be some form of photosynthesis going on here: ammono plants, using solar energy to turn respiration products — ammonia and cyanogen — back to methane and nitrogen, closing the matter loops. But cyanogen could only circulate in solution, not as readily as gaseous carbon dioxide in the air of Earth. That must mean the photosynthesis-analogue was going on in the oceans — some kind of plankton equivalent there. Perhaps there were no land-colonizing plants here…

Perhaps the creature whose back he rode was the flowering of the ammono-based life forms whose prebiotic chemicals he had glimpsed near Tartarus Base.

It was as he’d predicted to Benacerraf. It was Titan summer.

How about that. A hell of a lot to deduce from a few grains of cyanogen, Rosenberg. But it was comforting, hugely so, to be able to figure stuff out. And—

And the surface under him lurched. His bubble rolled. He tried to grab at the yielding wall but could get no grip. He slid down the wall, his chest rubbing against the soft, warm material, and finished on his front at the base of the bubble.

The bubble stabilized again. He climbed back up to his knees.

Beyond the rim of the corrugated surface, the ocean was receding from him rapidly, its oily ripples diminishing, and he could see the reflection of the swollen sun as a disc on the sluggish surface. His bubble sat on the back of a mass of flesh, maybe a hundred yards wide, a big flattened sphere. Those complex bruised-purple corrugations spread all the way to the rim. Maybe the creature needed a lot of surface area, for its bulk.

He could see a shadow sailing over the ocean surface. It was the shadow of his huge steed. There were ropy objects trailing beneath, maybe tentacles, waving passively in reaction to the breeze of the flight…

The shadow was under him. The damn thing was flying, now, like some immense chewed-up balloon. He was riding a jellyfish the size of a football field, as it flew through the green air of a new Titan…

Wonder battled with fear, threatening to overwhelm him. He longed to be enclosed: he longed for the cozy warmth of his EMU, the tight metal walls of the hab module.

…So how was it flying? He couldn’t see any wings, jets, propellers.

Anti-gravity?

Think, Rosenberg. Look for the simple explanation.

The thing was probably buoyant. Simple gas-bags, somewhere within this fat structure, would be sufficient to lift the jellyfish from the ocean, and up into Titan’s thick air.

There was something else riding the back of the jellyfish, about twenty yards from him.

It was another bubble, resting like a drop of water on the back of the ammono creature.

He threw himself at the wall of his translucent cage and stared across. It was like trying to see inside a droplet of scummy pond water.

He thought he saw something in there, an inert white form.

He shouted, banging on the wall of his bubble. He even tried to roll forward, within the bubble, to make the whole thing roll across the jellyfish, like a hamster in a plastic ball. But the bubble resisted his efforts.

His mind seemed to dissolve. To hell with the red giant sun, the new biosphere. All he wanted was to reach that other human being.

He was soon panting, his hairless flesh coated with a sheen of sweat.

He gave up.

Even if he’d got over to the other bubble there wasn’t anything he could have done to reach its occupant. If he could somehow breach this bubble — even if the temperatures outside were tolerable — the air of this new Titan was surely toxic, laced with hydrogen cyanide and ammonia.

But it was sure as hell worth a try.

He was finding it harder to breathe.

He felt an uncomfortable pressure in his bladder. He needed to take a piss.

He looked around. There just wasn’t anywhere to piss into, inside this sheer-walled, seamless bubble.

He tried not to think about it. But of course that didn’t help.

In the end, he just stood up in the center of the bubble, grabbed his dick, and let go. What else could he do? Warm urine splashed up over his feet. A puddle gathered at the lowest point of the bubble floor, green and frothy, and he stepped back quickly, trying to keep his bare feet out of it.

When he was done he retreated to the wall of the bubble, watching the urine lake. It spread slowly over the bubble floor, quivering as the jellyfish surged smoothly.

A shadow, wide and long, swept over the bubble.

Rosenberg flinched, raising his hands over his head, cowering naked against the floor of the bubble.

It was as if a roof had spread over the jellyfish, a ceiling of translucent, leathery skin, green-tinged; where the sun shone through, Rosenberg could see a coarse graininess, a sketchy skeletal structure.

The skin ceiling moved away, and sunlight, suddenly bright again, shone down into the bubble.

Rosenberg kneeled up and stared after the departing platform. It was like a kite, roughly diamond-shaped, the size of a 747. It glided, one pointed corner first, through the thick air. That papery flesh stretched over a frame-like skeleton. The anatomy seemed sketchy. There looked to be a spine along the axis, bulging in places; maybe there were organs — a digestive tract — in there.

It was like the pterodactyls of antique Earth. Or a Wright brothers fever dream, he thought.

This was Titan, Rosenberg reminded himself; the living things here could only be built from the raw materials to hand. And so, the bones of the kite-thing were probably made of water ice.

All along the leading edges of the diamond wings there were gaping cavities, like jet inlets. Maybe they were mouths; perhaps the creature fed on smaller airborne life forms, cruising like a shark. Like the jellyfish he was riding, the kite seemed passive, inert, as if saving its energy; he could see no sign of motion, anywhere across the kite’s huge frame. And that immense mass of skin showed another similarity with the jellyfish: a lot of exposed surface area for the kite’s mass.

He couldn’t see any legs, any means of landing.

Perhaps it never landed at all; perhaps it spent its life in the air, feeding on the airborne particles, even breeding there.

The pterodactyl receded, slowly, its sharp rectangular profile diminishing.

Rosenberg kneeled against the wall. The urine, cooling, lapped against his feet.

And now a dark form cruised over the surface of the ocean, far below him.

It was shaped something like a terrestrial ray, but it was immense. Those hundred-foot Titan waves broke like ripples in a bathtub over its oily, corrugated back; it had to be a mile across at least. Rosenberg could see vent-like mouths all along the ray-thing’s leading edges, and its back. It was turned to face the waves, but it didn’t appear to be moving; he could see no sign of a wake, no frothing or disturbance from any kind of impellers. He was reminded of a big basking shark, cruising through beds of krill and plankton, its huge jaw gaping. But this basker did not trouble to seek out its feed; it just sat in the prevailing current, waiting for plankton-analogue or whatever other organic goodies were suspended in the ammonia ocean to drift into its multiple mouths.

So, Titan life. There were common characteristics, he thought dully. Huge size. Large surface area. Passivity.

The jellyfish continued to rise. Now he was far above the surface of the ocean, and he had risen above the lip of the Cronos cliffs. The land on the plateau was a plain of grey-green ice, pocked with craters. Most of the craters were just sketches, palimpsests, their walls diminished by relaxation. The old craters were empty of their ethane lakes now, although he thought he could make out a purplish, filmy crust in the crater basins.

The world was split in two: an ocean hemisphere to his right, the flat grey-green ice of Cronos to his left. The horizon was blurred by mist and vapor, but curved sharply; the world was small and compact, a ball suspended in space, visibly smaller than the Earth.

He thought he caught glimpses of more baskers. Their delta shapes were arrayed across the surface of the ocean, like huge factory ships slowly processing the plankton-analogue.

Tiring, his lungs aching, he sat with his back resting against the pliant wall, his legs outstretched.

His thinking was feverish, getting fragmented, as if he was lacking sleep.

In fact he started to feel bored.

Now, that was just ridiculous. Here he was, somehow restored from death by Vitamin A poisoning, preserved across — oh, God — preserved across billions of years, maybe, and revived in an ammono-life ecosphere…

But he had nothing to do but sit here and sightsee. He wanted to get out there and do something. He wanted to take samples, run them through his lab in the hab module.

And he craved mundane things: to take a shower, read a book.

He wanted someone to talk to.

The sky, stained bottle-green by methane, was getting perceptibly darker. He must be rising out of the troposphere, the thick bottom layer of the air.

He looked up at the sun. Its bloated disc seemed a little clearer, though it was still surrounded by a faint halo.

He wondered if it was possible to see Earth from here. If Earth still existed, it must be lifeless: no more than a cinder, skimming the surface of the sun’s swollen photosphere.

No help for me there, he thought.

His chest was dragging at the air.

He tried to suppress panic, to keep his breathing even and steady.

Something was wrong.

He was going to suffocate in here, in this bubble suspended over the bizarre surface of a transformed Titan, here at the end of time. He would drown in his own exhalations, awash in urine—

A pillar thrust out of the surface of the jellyfish, ten feet from the wall of the bubble.

Rosenberg screamed. He scuttled backwards, over the yielding surface, getting as far as he could from the pillar.

To his shame, more urine dribbled out of his shrivelled penis and leaked over his legs.

The pillar was six or seven feet tall, maybe two wide. It was made of glistening crimson flesh. Its surface was like the jellyfish carapace: the same purple-black coloration, that complex ridging pattern. But the ridging was on a smaller scale, the gouges and bars separated by a couple of inches. It was topped by a cluster of large, complex-looking cell groups. Perhaps they were some form of sensor; perhaps he was being inspected.

Maybe it was here to give him more air, to feed and water him.

The pillar was utterly still.

The way it had moved was eerie. It had been reptilian: a burst of motion, followed by stone-like stillness. Perhaps it was that quality which made him feel so nervous and suspicious.

What did it want?

Take me to your leader.His ragged thoughts ran on in uncoordinated hypotheses, as his fear bubbled in his hind brain.

He coughed, and the pain in his lungs sharpened; black spots swam in his vision, clustering at the edge of his field of view.

He crawled forward, through the puddle of urine, to the wall facing the pillar. He slapped the bubble’s surface with the flat of his hand. “Can’t you see I’m dying in here? Why don’t you do something about it? Hey…!”

The pain in his lungs started to spread outward, up through his throat and out across his chest.

He slumped, resting his face and chest against the yielding wall. He slid down, onto his back. He could feel the cooling piss lap against his feet and lower legs.

“You weren’t expecting me to be conscious. You don’t know how to handle this, do you?”

Black flecks gathered at the periphery of his vision. Through the filmy upper surface of the bubble, the sky deepened to a rich emerald green. He was lying here in his own urine, gasping for air like a beached fish. What an end for mankind, he thought; what an epilogue.

There seemed to be something descending from the sky towards him: a broad, purple-black disc, a glimmering bubble, softly distorted…

He could see through it. It was a reflection, of his rising jellyfish, in some kind of translucent sheet above him.

They’ve roofed over the world, he thought.

He thought he saw more of those pillars, thrusting out of the carapace around him like fingers.

He tried to grip the plastic surface under him, struggling to stay conscious, to make this interval last as long as he could, before another unimaginable period of non-existence overwhelmed him.

But the cold green darkness was washing over him. He cried out as it pushed into his eyes, his brain; but he could no longer hear his own voice.

Paula Benacerraf had no memory of waking.

Suddenly, she was aware of herself again. It was as simple, and as brutal, as that.

She was standing. Everything seemed to be red. Her feet were cold.

She tried to look down, to see what she was standing on. When she moved her head, her eyes didn’t track properly, as if they were badly controlled automatic cameras, and her head seemed to slosh, a bag full of fluid.

The redness turned abruptly to grey, and there was a clamoring of bells in her ears.

The world tipped up around her. She saw a huge sky wheeling past, a sun like a dish of red light.

But it was taking so long, as if in a dream.

She collapsed gently against the ground, on her back. The landing was soft, but she could feel the spiky hardness of the ground, and where it pressed against her flesh, in a hundred places along the length of her body, it was ice cold.

Her heart’s hammering slowed, and some of the color leached back into the world.

That sun, straight above her, was immense. Much bigger in the sky than Earth’s sun, it was huge and red and dim. The disc was mottled with spots, complex black pits surrounded by crimson-grey penumbrae. She held up her arms, and moved out her hands, to accommodate the sun’s disc. Her hands finished up a yard apart.

She remembered her last walk to Cronos. The water. The seed packet. Her choice to die.

Oh, shit,she thought. I’m alive.

She felt — disappointed. Life would go on. She was going to have to eat, and drink, and sleep, and maybe figure out what was happening to her.

She’d have to make choices. She’d thought that was all over, for her. She felt cheated.

She closed her eyes. But the world wouldn’t go away, the gritty reality of it in her lungs, under her back.

So where was she? A hospital?

In the open air?

She opened her eyes, and lifted her arms. She was clothed.

Her hands were bare, but her arms were encased in long sleeves of some translucent material, like golden-brown polythene. She pulled at the material; it gave a little, but would not stretch, and when she pinched at her cuff it was impossible to tear.

She reached up to her face. There was no covering: no helmet, no visor, no face mask.

…She was in the open air, unprotected.

The shock reached her. She felt a moment of panic; she felt her lungs constrict, as if she was drowning.

She forced herself to relax. She took away her hands, opened her mouth, and deliberately sucked air into her lungs.

She wasn’t in an EMU. But wherever the hell she was, there was evidently an oxygen-nitrogen atmosphere.

She put her arms flat against the chill ground and tried to push herself up. As soon as she got her head upright, the ringing and greyness returned.

“Take it easy.”

The voice startled her.

“Lie back for a while.” A head moved into her field of view above her, silhouetted against the broad face of the sun. It seemed hairless, and the neck and shoulders supporting it were swathed in some transparent substance that caught the light. “I don’t think they got your fluid balance quite right. Orthostatic intolerance. It took me a couple of minutes to adjust, but it passes.”

“Rosenberg. I should have expected you.”

“Yeah.” He knelt down beside her. “Yeah, it’s me — I think.” He was wearing some translucent all-in-one coverall, which left only his hands and head free. And he looked younger.

“Good grief, Rosenberg. What happened to your hair?”

He laughed. “The same as happened to my eyebrows, and nasal hair, and chest hair, and pubic hair… I guess they forgot to put it back.”

“They? Who are they?”

“One step at a time, Paula.”

“You don’t have your glasses.”

He touched his face, looking surprised. “So I don’t. I don’t seem to need them. They grew back my foreskin, too.”

“They?”

“How are you feeling? Do you think you can sit up?”

“I’d rather stand up. This ground is freezing my ass off.”

Rosenberg laughed. It was a brittle, icy sound. He got an arm under her armpit and lifted; with his help she scrambled to her feet. She still felt dizzy, and her heart pumped a lot harder than she’d been used to, but she wasn’t going to faint again.

She and Rosenberg were out in the open. No hospital. No buildings at all, in fact. They were standing on some kind of plain. It was coated with sparse, low vegetation — stunted dark green bushes, a little grass — but there were no people, no cars or houses. The air was clear and her vision was sharp; the horizon seemed close by.

Off to her right was a long, straight, grey-white cliff which slid towards each horizon.

That big balloon of a sun still hung directly overhead. The sky and land were drenched in a dull dried-blood red. There were high icy-looking cirrus clouds, draped over the roof of the sky; some of them cut across the face of the sun and glowed crimson, as if on fire.

The only sound was the soft hiss of a breeze over the spiky grass.

This ain’t Seattle, she thought, with gathering dismay.

And Rosenberg—

Under his golden-brown translucent coverall, Rosenberg was naked.

He clamped his hands over his private parts. “Will you stop staring at my dick?”

She touched her scalp. It was bald and smooth, the skin cold to her touch. She glanced down. Under a translucent suit, past the low swell of her breasts, she could see her pubic mound, as bare as Rosenberg’s.

“Shit,” she said. She covered her breasts and groin with her arm and hands, while Rosenberg kept his hands clamped over his balls.

They stared at each other. “This is ridiculous,” she said at last.

“I agree. I won’t stare if you don’t.”

“It’s a deal.”

Deliberately, she lowered her arms; she looked him resolutely in the eye.

He laughed again. “A hell of a thing. We cross billions of years, and we bring all our dumb primate taboos with us.” His voice was brittle. Almost hysterical. And—

And he’d said, billions of years. “How long? Where the hell are we, Rosenberg? How did we get here, from there?”

“One step at a time, Paula. Come on.”

He turned away, and began walking slowly across the plain. His footsteps lifted him up in the air, so that he bounded forward in a series of short half-hops, Moonwalk style.

Oh,she thought.

This wasn’t even Earth, then.

She started to feel scared.

“Where are we going?”

“Damned if I know.”

She felt an absurd reluctance to move away from here, the place she’d come awake. As if she ought to wait here, on this anonymous patch of a uniform plain, until somebody came by to tell her what to do.

She sat down, ignoring the cold.

She didn’t want any of this. Choices, a structured world to figure out, even a relationship to manage. The hell with it. I did all this once.

She lay down and curled up, burying her head in her arms.

I want to go home, she thought. To Seattle. And if I can’t go home, I don’t want to be here.

But the world wouldn’t go away. She couldn’t even go to sleep, the ground was too hard and cold.

She opened her eyes.

The plain, the big red sun, Rosenberg waiting patiently, squatting on his haunches, a few yards away.

She got angry. She kicked at the ground, dug out great handfuls and threw the dirt around, rubbed it over her bare scalp. “Why couldn’t you leave me alone, damn it…?”

She got tired quickly. She stood there, panting, hot inside the suit, dripping bits of dirt.

Rosenberg just waited. He didn’t even watch her.

Reluctantly, she walked up to him. He got up, and walked on, and she followed.

Sensory impressions crowded in on her, unwelcome, forcing her to think, to analyse.

She found she was wearing some kind of booties, welded onto the suit, as clear as the rest of the coverall. When she lifted up her foot she could see there was no grip on the sole, no ridging, but she seemed to be able to keep her footing nevertheless.

The ground was a sandy, crusty, rust-brown soil; it crunched when her weight settled on it. There were stunted trees — they looked like willow, or birch — scattered over the plain; none of them came much higher than her shoulder. Between the trees, grass grew. Near her feet there was a splash of flowers, almost white despite the ruddy light, the petals as big as her palm. She knelt down and pulled up a handful of grass. She rubbed the blades between her thumb and forefinger; there was a sharp herbal aroma.

Rosenberg lifted up what looked like a mushroom, a huge puff-ball a foot across. “Mosses, lichens. It’s hard to see in this red light, but I’ll bet these things are livid green.”

“Chlorophyll?”

“Of course these aren’t true plants. They’re just organisms descended from some root stock, which have radiated to fill the various ecological niches…”

She dug up a little of her anger. “Radiated from what? What are you talking about? You’re so full of shit, Rosenberg.”

He said irritably, “Radiated from whatever terrestrial-biosphere samples the ammonos managed to retrieve from our bodies, or the ruins of our base, or the seeds you planted.”

“Ammonos?”

“I told you we had to take this one step at a time.”

She looked at Rosenberg. “You know,” she said, “I’m hungry. And thirsty. Shit. They had no right.”

“What?”

“To bring me back.”

“Yeah. Well, they did it. And I’m hungry too.” He shrugged. “Try anything. We’ve no way of knowing what’s toxic, even lethal… We have to trust the design.”

“You mean you don’t know?”

“Just try something, Paula.”

Near her legs grew a couple of the mushroom-like puffballs, some sparse grass, and a scratchy growth like bruised-purple heather. At random, she dug her hand into a puffball. It imploded, like a meringue, and a cloud of some kind of spores blew up around her arm, clinging to her flesh and the suit. She came away with a handful of the mushroom’s meat. It was white, soft, cold, slightly moist. She suppressed a shudder; the feel of it was repellent.

She lifted it to her mouth, bit off a chunk, and chewed deliberately.

It crumbled, collapsing to a hard residue, like bad sponge cake. It was still cold, and there was the faintest of flavours, an aftertaste of decay.

She swallowed the residue.

Rosenberg watched her intently. “Well, you haven’t choked, thrown up or keeled over.”

“But I’m even more thirsty.”

“Come on,” he said. “I think the ground dips down a little over that way; maybe we’ll find some fresh water.”

They began to walk, parallel to the looming grey-white cliffs.

They came to a stream.

It ran sluggishly through a shallow gully, eroded into the ground. The water was running away from the direction of the grey cliffs, Benacerraf noticed. It looked a little muddy, and dirty grey ice clung to its banks.

Rosenberg squatted and dipped a hand into the stream. He pulled it back quickly, but he brought up a little water cupped in his hands. “Ouch. Cold as all hell. I guess it’s glacier melt, running off those cliffs.” He stared dubiously into the little puddle he cradled. “Drink it, Rosenberg.”

He sighed. He lifted up his hand to his mouth, and sucked in the water noisily. He grimaced. “A little salty. It’s okay. So cold, though.”

She knelt down beside him, and began scooping up water. It splashed over her face, the cold stinging; and she could feel its icy passage down her neck and into her stomach.

Rosenberg said, “These suits seem to keep us warm enough. But drinking this stuff will bring our core temperatures down. We need to find a way to build a fire.”

“Those trees look as if they will burn.”

“We don’t have any way of lighting the fire.”

“Didn’t you ever go camping, Rosenberg…? No, I guess you wouldn’t. You take a couple of sharpened sticks, and—”

He held up his hands. “I believe you. Show me later. Just don’t lecture me about it.” He plucked at the chest-cover of his transparent suit. “I got a more urgent problem. I need to pee.” He clawed at the plastic-like sheet over his genitals, comically.

She realized that the cold water had run straight through her, too; soon she would face the same urgency as Rosenberg.

What were they supposed to do? Just let go, and walk around sloshing? Suddenly her suit seemed constricting, even claustrophobic.

She stood with Rosenberg, and experimented with his suit, pulling the clear material this way and that. At last, she found that if she pinched both sides of the suit’s neck, a seam opened up. Once the split began, it ran quickly along the lines of Rosenberg’s body, over his arms, down his hips and the sides of his legs.

Gently, Benacerraf pulled at the neck, and the front of the suit just peeled away from Rosenberg, like a parting chrysalis.

When the suit lay in a clear puddle at Rosenberg’s feet, he clutched his arms over his chest. “Christ, that’s cold.”

“Don’t be a baby, Rosenberg.”

He walked away, hopping gingerly over the icy ground on the balls of his feet. He moved behind one of the trees, and in a couple of seconds Benacerraf heard the heavy splash of urine drops against the soil, and saw wisps of steam rising around Rosenberg’s legs.

To get Rosenberg back into the suit, they found the easiest way was to lie him down, inside the back section. Benacerraf lifted the front over him and ran her pinched thumb and forefinger up over the opened seal; the material melded together seamlessly.

After that, she took her turn. Oddly, she felt naked out of the suit, even though it had been all but transparent. The ground was hard and icy under her bare feet as she squatted.

So here she was, eating and drinking and pissing and talking, life going on, just as if nothing had happened, as if the world hadn’t ended, as if she hadn’t died and been dug out of the ice and… hell, all of it.

It had never struck her before how much of her time, her conscious attention, was taken up just with the business of being human.

She rejoined Rosenberg, who stood by the stream. They looked at each other.

“Where are we, Rosenberg? Is this Mars?”

He looked confused. “No. Not Mars. Of course not. Mars is gone. This is Titan. Don’t you get it? You’re still on Titan, Paula.” He glanced up at the wide, flawed face of the sun, which filled the dome of heaven above.

Something connected in her mind. Cosmology lectures. Carl Sagan. “If this is Titan—” Oh, shit. “A red giant,” she said. “The sun’s become a red giant.”

He laughed brutally. “You figured it out. Just like I had to. Sorry there aren’t any comforting answers. We might be ten billion years from home, Paula.”

The ruined sun seemed to hang over her head, huge and heavy, as if it might crush her; she wanted to escape from it, run under a tree, hide her head with her hands. “Tell me what’s happened to us, Rosenberg.”

His face hardened further. “You want the short version? You died. So did I. We all died. We were frozen into the gumbo. Later — a lot later — aboriginal life forms dug us out and restored us. Quite a feat.” His voice was thin, trembling.

“We’re stranded here. Is that what you’re saying, Rosenberg?”

Again he looked confused. “Stranded? Of course we’re stranded. Who do you think I am, H.G. Wells?”

She felt a snap of irritation. “Lighten up, Rosenberg. I’m just finding all this a little hard to handle.”

“What the hell do you expect me to say? I woke up ahead of you, that’s all. This is as hard for me as for you. And I’m stuck here too.”

“No way home, huh.”

He frowned. “Paula, Titan is our home now. For the rest of our lives.”

She lifted up her face to the distorted sun.

She thought of home: of Houston’s sticky heat, the corroding sea air of the Cape, the fresh green of Seattle. It was impossible to believe that all of that wasn’t still up there somewhere: that huge, sunlit Earth, infinite and eternal, full of problems and dreams, the disregarded backdrop to her own life.

How could it all be gone?

“Come on,” Rosenberg said. “Let’s follow this brook downstream,” he said.

She shrugged. She didn’t have any better plans.

As they walked, he told her about the first time he’d woken, the glimpse he’d got of ammonia life.

They walked for a couple of miles, away from the cliffs. The ground started to slope downwards, as if they were walking down a long beach, and the stream became broader, its eroded banks more ragged.

At last, the covering of topsoil wore thin, and bare ice bedrock pushed through the surface like bone, pale red-grey in the light of the sun. Only a handful of plants grew here, clumps of the grass-analogue struggling to survive in the scrapings of topsoil. The exposed ice was sharply cold under Benacerraf’s feet.

They topped a shallow crest.

Before them an ocean stretched to the horizon, blood-red and murky, huge waves moving sluggishly across it. The liquid lapped at the edge of the shore, and flecks of ice crusted its surface.

Rosenberg grunted. “We’re on Titan for sure. Look at the size of those damn waves. And no tides to speak of.”

“What do you think the fluid is? Ammonia?”

He looked at her quizzically. “Of course not. The temperature’s wrong. It’s water. What else?”

She wrapped her arm around his. “You’re going to have to give me a little time, Rosenberg. I’m not so smart as you.”

“Then you’re lucky.”

“Come on. Let’s go find somewhere we can sleep.”

Maybe a mile inland from the water’s edge, they found a thicket of trees, with a thick blanket of topsoil and fat white flowers beneath. When they crawled under the layers of low branches, Benacerraf had a feeling of shelter; the shade shut out the unchanging, ruddy sky.

They ate and drank a little more. They tried to build a fire, Benacerraf rubbing sticks back and forth earnestly, but without any success. Maybe the wood needed to dry out.

They huddled together to sleep. They lay on the ground, back to back, then face to face. They couldn’t get comfortable, and Benacerraf was cold, even with her face tucked down into her suit.

She had an idea.

They stripped off their suits, and pressed their four halves together, pinching the magical seams. It took a little experimentation, but eventually they had made a kind of shapeless sleeping bag large enough to take the two of them.

They crawled into it, face to face. Rosenberg’s flesh, where it touched her at knees and hips, was hot. Soon the bag started to grow warmer.

Benacerraf felt something pressing against her stomach.

“Rosenberg…”

“I’m sorry,” he said miserably. “A primate reflex, here at the end of time. I can’t help it.”

“You’re so pompous, Rosenberg.”

She touched his face. It was wet.

She said, “What’s wrong?”

“Do you want a list? I want to go home. I don’t want to be stuck out here, like this, in the open air, trying to sleep in the daylight.”

“Have you lost your curiosity, Rosenberg?”

“No. But I hate not knowing what tomorrow will be like.”

“Rosenberg—”

“What?”

She reached out and ran her hand over his chest. Rosenberg’s body, shorn of hair, was soft, almost girlish.

She climbed on top of him, keeping the suit bag huddled over her. She bent down and kissed him gently on the mouth. “Let’s get warm, Rosenberg.”

“Yeah.”

He took hold of her hips, and pulled her down towards him.

There was a scratching sound, from a few yards away. Maybe it was a cat, she thought sleepily.

She had one arm stuck under Rosenberg. He had his thin back to her, and was snoring softly. Carefully she pulled the arm out from under him; it tingled as the blood supply was restored to it.

She rolled on her back. That huge, swollen sun still hung above her; maybe it had dipped down from the zenith a little way.

Morning on Titan:no birds were singing, no traffic noise, no radios or TVs blaring, no softscreen billboards shining.

Shit, she thought. It’s real. I’m still here. I’m stranded billions of years into the future. Earth is gone, and I’m on Titan, transformed by person or persons unknown.

Yesterday had been — unreal. Overwhelming. But waking up today, with a pain in her back and a gritty taste in her mouth, the reality of her situation seemed mundane. Even irritating.

And there wasn’t a cup of coffee on the whole fucking moon.

Away from Rosenberg’s warmth she could feel the hard coldness of the ground under her, and the chill air seeped into the improvised sleeping bag at her neck.

She had the feeling that Rosenberg was awake, but was lying there with his eyes closed, hoping the day would go away, or maybe that she would take some kind of responsibility for it all. She could understand that. Hell, how were they supposed to cope with this? Surely they both had some kind of post-traumatic stress to work through. And—

…What cat?

She rolled over and pushed up to her knees, resisted by the cramped, linked suits.

The creature was six feet away from them. It was the size and shape of a dinner table, and it picked its way across the ground on eight spindly, insectile legs, each maybe four feet long. The legs terminated in points, and didn’t leave footmarks. The main body, the table-top, was a corrugated, purple-black carapace; there were clusters of what looked like blackberries all around the table rim. The whole table-shape was swathed in a translucent golden-brown blanket, evidently the same material as Benacerraf’s suit.

Arms — six or seven of them — reached down from the underside of the table-top, and poked at the ground. The arms were skeletal bars of a glassy, semi-transparent crimson-grey substance, and Benacerraf couldn’t see how they moved; there was no evidence of anything like muscles or cables. The arms terminated in spiky claws with opposable thumb-like extensions. The claws dug gently at the surface, delicately picking up fragments and lifting them up to some kind of stowage under the table-top.

Rosenberg woke up with a start, his eyes puffy with sleep.

“What the—”

“Shut up,” Benacerraf hissed. “Look.”

He rolled onto his belly, his bony hip bumping against hers.

“Holy shit,” he said.

The creature, or artifact, was all but still. Only its arm-extensions worked, methodically picking over the soil. Occasionally a leg would rise, folding up delicately, and set down again. The motions were slow, deliberate, almost reptilian.

She had no sense of threat. The thing was so slow it was impossible to imagine that it could outrun humans, if it came to a chase. And besides, those limbs looked pretty fragile. Maybe they were made of water ice.

There were some heavy chunks of wood-analogue left over from the abortive fire from yesterday, within Benacerraf’s reach. If she had to she could reach out and find a club. It wouldn’t be hard to shatter those icicle legs.

The creature was standing over the patch of ground she had used as an improvised john yesterday, and it was taking salami slices off half-frozen lumps of feces.

“U.S. Cummings, I presume,” said Rosenberg.

“What?”

“Science fiction. Philip Dick. Never mind.”

“Rosenberg, I think it’s picking up one of my turds.”

“I don’t think you need to whisper,” Rosenberg said — but he was whispering too. The two of them were propped up on their elbows, inside their sleeping bag, like two kids watching TV in bed. “It must be aware we’re here. But I’m sure it’s not going to bother us.”

“You think it’s some kind of machine?”

“No. I think it’s alive. It’s an ammono creature. The coloration, the ridging on its back: all of that’s characteristic of the aboriginal life forms here.”

“How do you know?”

“I saw them, remember. Anyhow, you can see for yourself. Look at that blanket over the main body.”

“What is that, some kind of insulation?”

“No. Look at the frost; the temperatures in there must be low enough to allow ammonia to be liquid. Don’t you get it, Paula? It’s a spacesuit. The warming sun has brought the end of the world to Titan as much as to Earth. Now, this ammono animal is forced to take an EVA on the surface of its own planet.”

“So what’s it doing with my turds?”

“Sampling. Come on.” He struggled up to a kneeling position, and the last of their night’s warmth and musk dissipated. “Let’s get out of here.”

They shucked off the bag. Rosenberg pulled the suite apart, and Benacerraf hopped over the chill ground to a clump of trees, where she took a leak.

When she got back to Rosenberg, shivering, she found herself covering up her breasts and crotch until he’d helped her into her reassembled suit. It was odd, but she felt more embarrassed about her nudity in front of the thing Rosenberg had called an ammono than she had before Rosenberg.

The suit sealed up neatly around her, and warmed rapidly.

The two of them walked out of the little copse, and onto the plain. The ammono stayed behind, still sawing industriously at Benacerraf’s crap.

On the open plain, little had changed since the day before. The plain was just a gently sloping tundra, studded by the clusters of low bushes and scratchy grass, bordered at one side by the white cliffs of ice, and on the other by the black, oily, placid sea.

But now, there was movement — delicate, precise — everywhere.

The ammonos were scattered over the plain, from cliff to ocean’s edge. There had to be hundreds of them. And they all looked identical to the table-shaped creature which had disturbed them: the swathe of translucent blanket over the rectangular, ridged carapace, the spindly legs, the arms industriously scratching at the soil.

“They can’t all be taking samples of our dung.”

“Of course not,” he said, faintly irritated. “It isn’t us alone they’re interested in. It’s the whole of this biosphere.”

“Why? What’s the point?”

He pointed east towards the cliffs. “Come on. That way.”

“Why?”

“For one thing, that’s where the ammonos are coming from.”

She looked more carefully. Rosenberg was right. There was a greater density of the ammonos in the direction of the base of the cliffs.

“And for another—” He pointed upwards.

There was a contrail in the sky, white and sharp and unmistakable, scratched across the orange sky. It was rising up out of the east, from the land beyond the ice cliffs.

They walked.

She looked down on the ammonos as she passed them. It was like walking through a field of huge beetles. She could hear the soft clattering of the ammonos’ claws as they worked, a gentle sound like the click of cutlery on plates at some quiet restaurant. The ammonos dug blades of grass, complete little plants, out of the ground. They took black buds from the trees, pulling them gently away from their branches, and plucked seed packets from flowers. They seemed to be trying to avoid damaging the life forms.

When an ammono walked, its limbs would straighten out. Then icicle legs would ripple around the rim, flashing pink highlights, their motion too complex to follow. The table-top body of the ammono would glide evenly over the surface, through seven or eight yards, until it found another place to sample.

Actually, the ammonos hardly ever moved.

Only one in a hundred would be in motion at any time, save for the delicate clatter of limbs; this scattered herd of them together was almost stationary, eerily so, their Zen-like stillness quite unlike the chaotic jostling of terrestrial creatures.

She remarked on this to Rosenberg.

He grunted. “Paula, chemical reactions are dependent on temperature. By the time you get to the region where ammonia is a liquid — under thirty degrees below zero — you’re looking at a relative rate of maybe a hundred to a thousand times as slow as at room temperature for us—”

“You’re saying these creatures have a slower metabolic rate.”

“Much slower, yeah. You can see it in the way they move: those long periods of gathering energy, then a quick burst of motion. But it’s not going to be as simple as that, of course… reactions with the right activation energies won’t chill out, so they would be selected preferentially. And all that ammonia will have a complex effect, helping or hindering reactions. The only way to know for sure would be to take one of those critters apart, and see what’s sloshing about inside its carapace.”

That suggestion offended her.

She bent to pick a flower. “Maybe we shouldn’t be asking questions.”

“Huh?”

“Here we are at the end of time. Everybody we knew — everything we understood — is long gone. What does science, figuring things out, matter now? These ammonos seem to have given us a place we can live. Maybe we ought to be content with that.”

He laughed. “If my forebrain had an off-switch, I’d agree with you.”

She dropped the flower and walked on.

When she looked back, after a few paces, an ammono had crawled laboriously over to the flower and was picking it apart with its scalpel-sharp claw.

They took breakfast on the hoof. Benacerraf tore off handfuls of mushroom flesh and washed it down with water from an ice-flecked brook they found. She splashed water mixed with snow over her face and scalp; the cold was sharp and refreshing. One good thing about being hairless, she thought: at least it was going to be easier to keep clean.

As she walked on, her breath steaming ahead of her, she started to warm up. Soon she had to pull open the seams at her shoulders to keep cool. But the suit must be porous; it wasn’t trapping excessive amounts of heat and sweat.

“Somebody remade Titan, Rosenberg. Engineered it so we could live here. Breathe the air, eat the fruit. Who? People?”

“No. I think it was the ammonos, after the sun got too hot for them, and they had to retreat. Titan ice is primordial stuff, Paula. It probably contains dissolved carbon dioxide, ammonia, methane, organic molecules, sulphur, salts. When it melted it must have out-gassed volatiles. Good for building a new atmosphere.”

“Volatiles I can understand. But this is an ice moon. Where did the topsoil come from?”

“Any particulate matter in the ice would settle out, as dirt on the sea beds. Maybe the ammonos dredged that up. Hell, I don’t know.”

“They, Rosenberg? Why did they do all this? Why are we here, for Christ’s sake?”

He had no answer.

As they neared the base of the horizon-spanning cliffs, the ground began to slope upwards and grew harder and colder underfoot. The topsoil was sparser than on the lowland plain, the vegetation struggling to get a foothold, although there were still clumps of tough dune-like grass struggling out of cracks in the ice bedrock.

Soon it became more of an effort for Benacerraf to continue her steady Moonwalk bound over the surface.

There were fewer ammonos here; in their shining transparent suits they trooped, in their reptilian spurts, back and forth, evidently shuttling between the plain and some kind of base on the Cronos plateau.

A wind blew up, pushing parallel to the cliff face and across their path. Clouds shouldered across the sky: fat cumulus clouds of water vapor, just like Earth’s. And then a rain began to fall, big fat heavy drops that descended with a snowlike slowness, and splashed noisily against her golden-brown suit.

The horizon disappeared, and an orange-grey mist closed in around her, obscuring the cliffs.

Rosenberg came up to Benacerraf. He had slipped his hands inside his sleeves, and wrapped his arms around his body; rivulets of water ran down from the dome of his head. “If this cliff is the edge of Cronos,” he said, “we’re heading due east, roughly.”

“Or maybe west,” she said. “We don’t know which side of the continent we’re on.”

He shook his head, and water sprayed off around him. “No. This has to be the western periphery.”

“How do you know?”

He pointed upwards, then tucked his hand back under his armpit. “We can’t see Saturn. I figure we’ve been returned to the region of Tartarus Base. Anyhow, the winds are blowing out of the north. Which is what I expected.”

“How come?”

“Titan is still a small world, Paula. The weather system is going to be simple. Like on Earth, the sun’s heat at the equator pushes up piles of moist clouds. The clouds flow north and south, dumping their rain on the way. But here, the gravity is so low and the distance to the poles so short that I’d expect the hot air to make it all the way to the poles. When it descends, that’s where you’ll find the deserts…”

Mercifully, he stopped talking.

Benacerraf looked up. The huge sun was visible as a brighter disc above the grey-white clouds. Raindrops, fat and slow, fell towards and around her, like a hail of bullets falling from infinity. Some of them had turned to snow, now, and they swirled languidly in the updraughts.

She was shivering; the rain on her bare scalp was cold and actually painful. The few ammonos here had their arms tucked under their carapaces, and rain puddled on the clear coatings over their backs. And now the rain actually seemed to be getting harder, turning to sleet.

“Shit, Rosenberg. Understanding the mechanics of the weather wouldn’t help me half so much as a hat.”

He nodded, his motions jerky, shivering. “Let’s keep moving. At least that will keep us warm. This can’t last forever. Maybe we’ll climb above it.” He set off.

She tucked her head into her shoulders, folded her arms across her body, and walked after Rosenberg, who was already receding into the misty haze.

The walking didn’t require much attention, and, like her walks on Titan before, she tried to lose herself in daydreams, fantasies, to escape the dull reality of the world.

But the dreams wouldn’t come.

Maybe the ammonos had rebuilt her, but they didn’t seem to have put back her imagination. Or maybe there was some part of her which knew there was nothing much for her to dream about.

By the time they reached the foot of the cliffs, the rain had stopped, but there was still a thick layer of laden cloud which obscured the upper reaches of the cliffs. The cliffs here were steep and forbidding, thrusting out of the ground like a wall, their base littered with some kind of loose scree.

Rosenberg went forward and tried to clamber over the scree, but it was slick with half-frozen rain, and the fine plates slid over each other easily. Despite the buoyancy of low gravity, Rosenberg slipped, repeatedly, and stumbled.

After he bloodied his nose he gave up.

The chaotic clusters of ammonos had reduced to a couple of files here, like columns of ants. They were going head-on at the cliffs, without hesitation; their legs seemed able to clamp onto the slick ice surface, and they hauled themselves straight up even the steepest sections of the cliff. Looking up, she could see the trail of ammonos dwindling into the mist and low cloud above, their carapaces dark stains against the dull grey-red surface of the ice cliffs.

“I wish I had their legs,” Rosenberg said, rubbing his mouth. “Come on. We’ll follow the cliffs a ways. It can’t all be as tough as this.”

They stood, shivering, each waiting for the other to lead. Neither of them wanted to do this, she realized. The truth was, they both just wanted to go home.

She said, “Which way? North, or south?”

“You choose, Paula. What difference does it make?”

“North, then.” She turned to her left and began to walk. “And if we walk all the way to the pole and find a desert there, I’ll know for sure you’re a smart ass, Rosenberg.”

“That’s my job,” he said, wiping blood from his lip.

After a couple of hours of steady walking over the slick ground, they came to a narrow gully. As far as Benacerraf could see it was incised all the way up the ice face, and into the clouds above. It looked as if it had been cut by a stream, which was now vanished.

At the foot of the gully there was a short section of the treacherous scree. She stepped carefully over this, watching her feet.

Then she came to the gully itself. Its mouth, at the base of the cliff, was broad, and there was a litter of topsoil, evidently washed down from the gully sides or from the Cronos plateau above.

She walked forward. For a hundred yards the going was easy; the ground sloped up steadily, but the gully was broad and paved with gritty, rough topsoil. But soon the walls narrowed around her, and the base of it narrowed to a thin V. She had to walk — climb, in fact — with her feet splayed outward, braced against the gully’s two sides.

As she climbed, the grip of her soles became less reliable, and her feet slipped from under her. The clutch of gravity was feeble, but the pain was great as she banged her knees and hips against bone-hard ice. Her bare hands soon started to turn white and numb from the cold of their contact with the ice. She pulled her sleeves down over her hands and gripped the cuffs in her clenched fists. But that wasn’t satisfactory, because the stretched material rubbed painfully at her shoulders and the back of her neck. And besides, it was almost impossible to get any grip without opening out her fists.

Her world closed down to the aches of her body, the few feet of ice gully around her, the eroded surface in front of her face, the focused search for the next handhold. She couldn’t even move fast enough to work up a decent sweat, and she grew steadily colder. She was a billion miles from home, aeons in the future, but as her discomfort closed in she might have been anywhere, she thought. Her irritation turned to misery.

She climbed into a layer of billowing mist. The droplets of water vapor were hovering balls the size of her thumbnail, and they caught the diffused crimson light of the sun. They looked too big to be suspended in the air, but here they were, the swirling updraughts easily counterbalancing Titan’s feeble gravity. Walking through them was something like entering a zero-G shower. When the droplets hit her translucent suit they splashed but didn’t stick, and secondary droplets spun away, shimmering. But the drops that hit her face and hands and bald scalp spread out rapidly and soaked into her. Water started to seep inside the suit, at her neck and cuffs.

She tried to wipe the excess liquid off her face with the edge of her hands, or her cuff. The mist as it dried was leaving a fine residue on her flesh, a sticky organic scum.

She ached all over. The hell with this. She started to get angry.

If she couldn’t lose herself in daydreams of past or future, then maybe she ought to concentrate on the present, the obstacles she was facing, how she could make things easier.

Crampons, for instance.

Maybe she could improvise something from those scrubby trees on the plain. A flexible branch, maybe a rope woven from some kind of creeper.

She needed gloves, of course. And a hat. Maybe they could sew together some kind of fabric of leaves.

She thought about knocking over one of those ammonos. That might solve all their raw materials problems. But if Rosenberg was right, the ammonos, inside their chill spacesuits, were breathing out ammonia and cyanogen. Slicing open one of those suits would not only kill the ammono, it would do the two of them a lot of damage too.

Anyhow, such violence felt wrong. This wasn’t her world, after all.

So: hats of leaves, or bark. Maybe they could stuff their suits with grass and lichen to improve insulation. They would have to do some kind of inventory of the vegetation here: investigate what they could eat, what they could use for other purposes, like construction and even medicine…

Thinking, planning, wiping the waxy organic sheen from her face, Benacerraf continued her climb.

At last the gully grew narrower. Looking up, Benacerraf could see she faced maybe ten or fifteen feet of sheer ice, beyond which the land flattened out. She could see tufts of grass-analogue bristling out from the lip of the plateau above her, black and wiry.

It wouldn’t be a difficult climb, she thought. Just a little scary.

She looked down. She’d risen almost all the way out of the mist layer now, she realized. The mist was a lumpy grey-white ocean beneath her, from which thrust this ice cliff. She could make out Rosenberg, as a toiling pink-brown speck in the mist layer, perhaps a hundred feet below her.

She turned again, lodged her fingertips in crevices in the ice, and hauled herself upwards. The low gravity worked in her favor, and the climbing here was actually easier than the slog up the gully.

She reached the top in a few minutes, and dragged herself up over the edge.

The land flattened out here to form a plateau, sharp-edged by this ice cliff. Further off, she could see no sign of further uplands, although a shallow wave-like ridge in the ice hid much of the landscape from her. There was grass growing close to the cliff lip, and some of the swollen mushroom-like things. A layer of thin cirrus cloud coated the eastern sky, stained red by the light of the aged sun.

She peeled open a couple of seams to cool down. She sat at the edge of the cliff, her legs dangling over.

Rosenberg took a further half-hour to reach her. He hauled himself clumsily up over the last lip of rock and threw himself flat against the ice, his arms outspread. His face was coated with a thin frost rime.

“I never thought,” he said, “I’d be so pleased just to be somewhere flat.”

She scraped the frost off his skin with her fingernails. “You’re not a physical kind of guy, are you, Rosenberg?”

“Oh, I’m learning to be. Boy, am I learning.”

She collected some food, mostly mushroom flesh. They drank ice-cold water from a small rivulet nearby, that fed the bigger system that had carved out the gully they’d climbed.

When his breathing had gotten back to normal, Rosenberg pushed himself to his feet. His hands and mouth full of mushroom flesh, he did a slow scan of the world from this new vantage point. He gazed down over the grey, lumpy clouds that covered the lowlands, then turned and looked inland.

He stopped. Even his jaw ceased its chomping.

“Rosenberg? Are you okay?”

He was staring inland, a green light reflecting from his face. “Stand up,” he said. “Stand up and look at this. My God.”

She got to her feet, her legs still aching, and stood alongside him.

The sky to the east, over the interior of this ice continent, had cleared; the cloud layer was breaking up. The sun was a huge blood-red ball, battered and pocked, dominating the orange sky above.

There was a layer of green light at the horizon.

At first she thought it was a smog belt. But it was flat and sharply distinguished, at its upper edge.

It was a roof.

There were tall trees — no, towers — evenly spaced within the green. And the towers were tall, she realized now; they were poking above the horizon, their bases hidden by the curve of the moon.

Some huge form, diamond-shaped, moved between the towers, within the roofed enclosure.

“My God,” said Rosenberg. “I was starting to think I dreamt it. That’s where I was, the first time.”

The first time? “Where?”

“In there. That’s a worldhouse. The last refuge of the old ammonia-based life system. It’s like a greenhouse. Except, colder within than without. In there, the conditions must be as they were when the ammono life was at its peak, when it covered Titan. That’s where they retreated when the sun got too hot, when the ammonia oceans started to boil and the bedrock melted. It must be where these ammono beetles are coming from now.”

“It’s like our CELSS farm.”

“On a gigantic scale… Oh.”

The mist in the air was lifting. And in the east — beyond a horizon obscured by that immense artifact — Saturn was rising.

Saturn was autumn brown, against the green sky. Perhaps a quarter hemisphere showed. Time seemed to have been kind to the huge planet: Benacerraf could make out the familiar bands of cloud, tipped up almost vertically towards the ruined sun, and the splashes of white that marked interior-driven storms…

“The rings,” she said. “Rosenberg, what the hell happened to the rings?”

The planet’s huge face looked denuded, without that narrow, tilted-up ellipse of banded light, the matching, complex shadows in the cloud tops.

Rosenberg said, “They were only chunks of ice, Paula. I guess it just got too hot.” He threw down what was left of his mushroom and dusted off his hands. “Let’s go see what’s over the next ridge.”

He stalked off, eastward. He bounded away, taking big bunny-hops, and was soon fifty yards ahead of her.

His mood had swung to its manic, energetic pole, she thought gloomily.

She followed more sedately, trying not to pine for Saturn’s rings.

The ridge, maybe fifty feet tall, was a pressure wave frozen in the ice, and easy to climb. Rosenberg waited at its crest for her.

From the crest, the landscape seemed to open up, as the horizon receded to the east. The land beyond the ridge was pretty flat, though in places cracked and compressed.

At the foot of the ridge there were beetle ammonos, the first she had seen since leaving the plain. They toiled in complex patterns across the barren ice fields here. They made their way in roughly radial patterns to what looked like a jumble of low hillocks at the center of the plateau, neatly sliding over or around the worst crevasses. That cluster of hills was perhaps five miles from them and a half-mile across, or less. The hills thrust irregularly out of the plain, their contours rounded, as if melted, their facets glimmering in the light of Sol and Saturn.

Glimmering.

Actually, it looked like a downtown.

“Oh, my,” Rosenberg was saying. “Oh, my.”

“That’s artificial,” she breathed. “Isn’t it, Rosenberg? Holy shit. Those aren’t hillocks. They’re buildings. That’s a city.”

“Oh, my.”

They both moved at once, as if some spell had broken. They hurried forward, hopping carelessly down the side of the ridge. Rosenberg led the way, and the pace he set was more a half-run than a fast walk. The ice here was flat and not too badly broken up, and it made for fast progress. Even so, Rosenberg tripped a couple of times.

A part of Benacerraf would have liked to take this a little slower. One bad fall, one twisted ankle — or, worse, a break — could be a catastrophe for both of them.

Part of her felt like that.

The greater part of her soul was with Rosenberg in his desperation, running ahead of the constraints of the ice, running ahead of caution, to the city on the plain.

They ran more frequently into files and clusters of ammonos, as they picked their way earnestly across the ice. Benacerraf, with her residual caution, tried to avoid the ammonos. Not Rosenberg, though: his head was up, and he simply ploughed through the ammonos’ orderly ranks. But they reacted smoothly to him, their files breaking and reforming as he stomped through. It was like, she thought, seeing a column of gigantic ants skirting a boot placed in their path.

Even Rosenberg slowed, though, as they reached the edge of the city.

It was, she thought again, like walking into a downtown.

The structures here were grotesque spires of ice: some, she guessed, were more than a half-mile tall. The nearest was an octagonal pillar, tipped away from her, Pisa-like. The ground around its base was littered with irregular blocks of ice, some feet high. The surface beneath was smooth ice, as flat as a freeway. And slick, with a thin layer of surface water. Like an ice rink.

Machined.

She clambered past the worst of the ice blocks and walked forward, across a free stretch of floor, until she reached the wall of the structure. She looked up at it. The wall, one of the eight comprising this octagonal cylinder, narrowed as she peered up, merging at infinity with its neighbors into a crimson-grey line.

Suddenly, staring up at the pillar, she felt giddy, as if with reversed vertigo; some primitive primate fear, as Rosenberg would say, that the thing might tumble down and crush her seemed to be about to overwhelm her.

She put out her hand. She touched a cold, hard surface.

The ice was like rock, but there was a slickness to it. When she pulled away her palm, her skin was wet. And now she looked more closely she could see the edges of the building, between the huge facets, were smoothed over.

The building was melting.

She heard Rosenberg’s footsteps receding, so she hurried around the octagonal pillar and followed him, proceeding deeper into the city.

It was like walking through an ice-sculpture caricature of Manhattan. The buildings — spires and pillars, even some narrow, inverted cones — towered over her, their washed-out crimson-grey lines obscuring the sky. In some places she could see lacy bridges connecting the peaks of the structures, but there were a lot more stumps and broken arches than complete spans. The narrow, regular streets between the buildings were cluttered up with rubble, smashed-up ice fragments, some of them huge.

About all of this there was a sense of smoothing out: of rounded corners and edges, of melting. There were even icicles dangling down from the stumps of bridges. Most of the buildings seemed open, with immense arch-like doorways like cathedral entrances. When she peered inside she found nothing but scattered rubble.

The ammono beetles toiled in thin files towards and away from the dense center of the city. With what seemed an inexhaustible patience they worked their way around the innumerable ice-fall obstacles that cluttered up the orderly streets; if she watched for a while, Benacerraf observed that the ammonos always followed the same path around each obstacle, like ants following a biochemical trail.

She met Rosenberg at the center of a small square, bounded on all sides by elephantine ice walls. He was peering up at the huge buildings. There was water on his cheeks; it shone in the pink-grey light of the ice walls.

“All the damage is at ground level. See? That’s where the walls are smashed up and cracked…”

She looked at the building with new eyes. “You’re right, Rosenberg. So how did they get this way?”

“Isn’t it obvious? They fell, Paula.” His eyes were a red-rimmed mess, she noticed. Evidently his mood had crashed again. “Suppose you were building, here on Titan, in this one-seventh gravity and all this thick air… Wouldn’t you build up as high as your materials could go, huge Gothic structures, stilts and spires and bridges miles high? Why, you could pump your walls full of air and use buoyancy to get even more of a lift… But then the sun blew up, and the damn stuff just started melting.”

She walked up to him and took his hand. “Shit, Rosenberg. You’re crying again.”

He looked down at her. “Don’t you get it? Look around you: the ancient, ruined crystal city… This is Xi City. Maybe the houses turn to follow the sun—”

“What?”

“Didn’t you read Bradbury? This is the way the Solar System was supposed to be, Paula. This is why we went to the Moon, why we sent out the probes to Mars.” He walked a few paces ahead, and turned around, his arms outstretched to the huge, sculpted ice walls. “This was what we were looking for all the time. This! It’s just come billions of years too late, is all. Damn, damn…” He ran a hand over his face, smearing tears and snot. “I’m sorry.”

“I know. Come on, Rosenberg.”

Hand in hand, they walked on, deeper into the heart of the crystal city.

A few hundred yards further in, the buildings thinned out, and the crimson light grew brighter; it was like entering a clearing at the heart of a forest thicket.

Benacerraf led the way through the clutter at the base of the last of the buildings. When they stood at the edge of the clear area beyond, she could see across it to the buildings at the far side, maybe a quarter-mile away.

The floor here was clear of the debris of falling rubble. And there was a single structure, as far as she could see: a slim spire maybe twenty feet tall, at the geometric center of the clearing, dwarfed by its skyscraper cousins.

Ammonos moved in complex, interlacing files across the surface. The clearing was roughly circular, and the blank faces of structures walled it in on all sides, as if fencing off the now cloudless crimson sky.

The spire-like object stood at the center of an inner disc of ice, which was clear of even the smallest loose debris; in fact, she thought, it looked as if it had been repeatedly melted and refrozen.

She noticed that the ammono beetles studiously avoided the melt crater, even if they had to take a long detour to do so.

The spire was actually slimmer at the base than at its tip, and now she looked more closely she thought she could see some kind of opening at the top there, pointing up at the face of the sun.

Like an air-scoop mouth, she thought.

And at the base of the spire—

“Fins,” Rosenberg said beside her, pointing. “The thing has fins, Paula. Will you look at that.”

“It’s some kind of rocket, Rosenberg.”

He frowned up at the scoop. “Methane. That’s the propellant. Methane, scooped out of the atmosphere and burned in oxygen, mined from the water-ice.” Now he scratched his bald head. “God damn, Alan Nourse had it right after all.”

“Who?”

“Never mind… I think we’d better get out of here.”

“Huh? Why?”

“Look around.”

The ammono beetles had gone.

Rosenberg said, “The ammonos have built Cape Canaveral in the middle of Xi City. I guess I don’t want to be around when the ship goes up.”

He reached for her hand. Together they walked away from the methane rocket.

They found a valley, maybe a mile from Xi City. It was just a rough gouge in the ice, but it afforded some shelter from the wind. And on its floor there was a shallow, running stream, and clumps of grass-analogue, and some of the mushroom plants.

They zipped together their suits and huddled close beside each other. They sat facing Xi City, and munched mushroom flesh. “So how long do you think we have, Rosenberg?”

“How long?”

She waved a hand. “Before we lose all this. For instance, it’s too hot for Titan to retain an atmosphere now. How come the air doesn’t evaporate?”

“Oh, it is evaporating,” he said. “But it will take a while. The oxygen atoms at the top of the atmosphere must be bleeding steadily into space. But the mass is big… Paula, it will take tens of millions of years for all this air to leak away. It’s like melting the bedrock ice. It will take a million years or more to melt even a few miles of ice, and there are hundreds of miles under us. You have to think in terms of planetary masses, Paula. Nothing happens suddenly. Anyway, it makes no difference. The sun won’t keep still that long. I think it has some growing to go before it’s done with its red giant phase.”

“How do you know?”

“Because this place is so damn cold. The black-body temperature here will be closer to nine hundred degrees, when the giant phase reaches its climax…”

“Shit.”

“Yeah. The atmosphere will evaporate first. Then the ice mantle will melt, and boil away. Nothing left but the rocky core.”

“How long?”

He shrugged. “I’d say we have a hundred thousand years.”

“A hundred thousand years. Not much.”

He grunted around a mouthful of mushroom. “Only twice as long as the human species existed before we were born. You just don’t think big enough, Paula.”

“No. Hell, I guess I never did. So,” she said. “What are we supposed to do now?”

“I guess that’s up to us. We could try to talk to the ammonos. You know, I’ve been thinking about why we’re here.”

“You have?”

“Yeah. Think about it. They terraformed their own planet. They rebuilt our biosphere, or a copy of it, from what we left behind, as best they could. And they found us in the ice, and managed to… repair us. But I don’t think they understand what we are. They don’t react to us, except as some kind of animal, and they’ve made no attempt to communicate with us. Paula, they might not even know we’re intelligent. Yes, talking to the ammonos would be a hell of a challenge.” He looked up. “Maybe they could tell us what happened to Earth, to mankind. Maybe I could make a telescope. Grind some ice into lenses. It would be interesting to see what else is out there.”

“What else?”

“We could fly here.”

“We could?”

“The light gravity, the thick air… Da Vinci flying machines would work.” He frowned. “Maybe some kind of winged bicycle would be the best solution. Hell, it would be easy. You could glide most of the way. I’ve seen it done. And then we could think about making our own methane rockets. Maybe we could even borrow some of the ammonos’ technology. Paula, this is a moon, but a big damn moon. We can explore it from pole to pole…”

After a time, Benacerraf sat back. “Plans and schemes. Busy, busy, busy. But what’s it for?”

“Huh?”

“Rosenberg, this isn’t some dumb camping trip. It’s not even an EVA. We’re the last survivors of the human race, stuck here in the far future. Are we supposed to repopulate the planet?”

He coughed, spraying out mushroom. “Sorry,” he said, wiping fragments off their joined suits. “I wasn’t expecting that. I sure as hell am no Adam.”

“And I ain’t no Eve,” she said firmly.

Anyhow, the phrase reminded her uncomfortably of Bill Angel.

“I don’t think we need to,” Rosenberg said. “I think I know what that rocket ship is for.”

“It’s pretty damn small,” she said.

“Huh? The rocket?” He looked puzzled. “Small for what?”

“For an evacuation. Titan is doomed, right? But you wouldn’t get a single ammono beetle in that thing.”

He laughed. “You’re thinking like a human, Paula.”

“What do you expect?”

“That’s not a human artifact. And what lies behind it isn’t a human motivation. You have to learn to think like an ammono. We’re dealing here with a race who, when confronted with the destruction of their world, retreated into their worldhouse, and rebuilt their moon to accommodate us. Terrestrial life. Can you imagine humans doing the same?”

“What are you saying?”

“I’m saying these guys think big. Bigger than we ever did. But in a different way. I think they are trying to save their biosphere. And ours. But they’re doing it the way we should have done it. And could have, if anybody had provided the funding.” He looked up at the sun’s diseased face. “But we weren’t smart enough, Paula. We blew it. We dropped a fucking rock on ourselves. We lost ten billion years. We might have covered the Galaxy by now. But we blew it.”

“I think we did okay, Rosenberg,” she said gently. “We’re here, aren’t we? We came to Saturn, and in the end, we found something wonderful. And if you’re right, because of us, Earth life is going to live on, to survive even the death of the sun… Do you think this is what it was all about? All those millennia of struggling, the whole bloody human story, just to deliver the two of us, here, to the end of time…?”

The light around her changed. She looked up, to the east. The sun, a broad, ruddy disc, was descending towards Saturn’s limb. The grand, slow eclipse had started, she saw, with a perfectly circular arc of darkness bitten out of the sun’s swollen face, and red sunlight glimmering around the rim of Saturn, the layers of atmosphere there. She thought she could see the shadow of Saturn sweeping like a wing across the plains of Cronos towards her, and the air grew dark and subdued. She thought she could see a fine, glittering line stretching up towards the zenith: perhaps the remnants of the rings.

…Hey, Paula. Scuttlebutt from home. Some double-dome from JPL is saying he’s found life on Titan…

Benacerraf could feel the elemental human warmth of Rosenberg’s bare skin, all along her flank, from shoulder through hip to ankle.

They planned further.

Today they should try again to build a fire, she said. With a fire they could warm themselves, heat up some water, maybe try cooking some of the vegetable life and see if that improved its flavour.

And beyond that they ought to think about a shelter. Maybe they could construct some kind of log cabin from the wood-analogue of the trees here. But it might prove difficult to cut the wood. Ripping off small branches for a fire was one thing; carpentry for a serious construction would be something else, without metals to work into tools.

Rosenberg started talking longer term. There might be metals to be extracted, from meteorites embedded in craters in the ice…

To the east, over the shadowed ruins of Xi City, white rocket light flared.