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.