“El Dorado,” he said. “I guess we made it. It looks just like in the radar images.”

She stared at the crater floor gumbo. She could see that it wasn’t the uniform purple-black bruise, color she’d become used to, back around Clear Lake. Purple predominated, but there were streaks of lighter reds — even a trace of scarlet — mixed in. The whole mess looked like a puddle of oil paints, the multiple colors mixed up and streaked together.

“Well, it’s different,” she said. “Do you think there’s kerogen?”

“I can’t tell,” he said testily.

“Try your IR.”

He reached up to switch on his night-vision visor. “I don’t know if this tells me anything or not.” Then he lifted his head, and in his visor she could see the reflection of the mountain, the orange sky.

“…Oh, wow,” he said. “Look up there, Paula. Use your infra-red. Oh, wow.”

She turned on her own visor, and looked up.

Through the milky-gold haze, beyond the feathering of cirrus cloud, was rising the huge, multicolored crescent of Saturn.

It was almost local noon here, so the sun was directly over her head. Saturn looked as if it was tipped on its side, a half-shadowed hemisphere with its bright round belly thrusting upwards. And jutting ahead of the globe of the planet, pointing vertically up towards the sun, she could see the brilliant rings, thin, striped ellipses.

It was the first time she had seen Saturn since they had dropped out of orbit;

Suddenly she realized where she was. It was a surge of perspective, as if the walls of the Universe opened out around her.

She had let this sunless bubble-world of ice and gumbo and haze and crotch rot eat into her imagination, until it was as if the gumbo extended on, beyond the visible, to infinity.

In fact, she was crawling over a ball of ice, a billion miles from the warmth of the sun.

I’m on Titan, she thought. Here I am — Paula Benacerraf, human, American, grandmother — gazing up at the rings of Saturn.

I made it.

They camped in the lee of the crater wall, on the edge of the chaotic terrain.

Rosenberg, a shapeless mass in the layers of his grimy suit, crawled over the tent floor and inspected Benacerraf’s feet. That early injury to her right foot still hadn’t healed up, and now she had frostbite in a couple of the toes of her left.

Rosenberg himself had developed some kind of tremor, rendering his own fingers too clumsy to apply the scalpel precisely. Benacerraf did most of the doctoring for both of them now.

Under Rosenberg’s direction, she lanced the swollen lump on her right foot, and the worst frostbitten toe on the left. Multi-hued liquid matter pulsed out of the new wounds.

The throbbing pain ebbed slightly.

“I don’t think that right foot of yours is good news, Paula,” Rosenberg said. “I think you have a deep-seated infection in the bone itself.”

“Terrific,” she said.

“I’ll increase your antibiotics. We still have some Metronidazole and Flucloxicillin. They’re not the most effective, but—”

“It’s all we have. I know.”

She used the scalpel to slice off squares of paraglider fabric, and plastered them all around the wounds. She pulled her socks back over her feet, wincing when the fabric tore at her new incisions.

She helped Rosenberg pull open the layers of his own suit. She had to pull carefully at the fabric, she found, or she would tear away great transparent strips of flesh, like sheets of onion-skin. The flesh seemed loosely attached, but nevertheless caused a lot of pain to Rosenberg when they came loose.

It was scary. She had problems herself, but loose skin wasn’t one of them.

Inside the suit she could feel Rosenberg’s ribs, the bony ledges of his pelvis, the slack thinness of his legs. The bulk of the suit masked this degeneration; out on the surface all she could see was his clumsiness, his slumps and lousy posture. It was astonishing he could walk at all, let alone haul a heavy load across the surface of Titan.

She rubbed cream into his armpits and stomach, the raw regions of his crotch. She even worked the cream into his frost-nipped penis, which was still swollen and sore.

Hemorrhoid cream was all they had left. But it seemed to soothe.

She hated to do this, to be so close to another human. She’d make a lousy nurse, she thought. To get through, she made herself think of how she’d handled Jackie as a kid.

He lectured her about their Belsen-like boniness.

“It shouldn’t be a surprise, Paula. We’ve been expending calories at a hell of a rate. More than we’ve been replacing them with food. We’re slowly starving, in fact. We’ve already metabolized a lot of our body fat, shifting it as a fuel supply into the bloodstream. All this is part of our bodies’ strategy to cope with what we’re putting them through: heavy exercise, without enough fuel. Our bodies are eating themselves up, trying to keep going as we demand…”

“Eat your soup, Rosenberg.”

With his hands swathed in lengths of parachute canvas, Rosenberg tried to raise his soup spoon to his lips. His hands shook too much, and the spoon clattered pitifully against his teeth, like a bird tapping on a window.

She put her arm round him to steady him, and guided his hand to his mouth. He sucked the soup gratefully.

Later they lay, back to back, in the confines of the tent. There was nothing before Benacerraf’s eyes, through the window of her helmet, save a patch of plastic wall reflecting the dim low-energy bulb, and a couple of piss bags, slowly freezing.

“You know, Paula—”

“What?”

“Sometimes I want to give up. Just stop. Lie down on the ice, or in the granules or the gumbo or whatever damn stuff, and just stop. Go to sleep. You know?”

“We can’t call in a rescue chopper.”

“I know, Paula. It makes no damn difference.”

She lay silently for a moment. “Then why do you go on?”

“Why do you?”

She thought that over.

“Because of Jackie.”

“Your daughter.”

“Yes. And her kids. In case they’re watching me, the stills and video we transmit.”

“Paula, we haven’t heard from Houston since—”

“I know. I didn’t say it was logical.”

“So it’s the clan. Right? You got the clan in your heart, even here, a billion miles away, on Titan. So far away you can never do anything to affect them again, for good or ill, or they you. Even though the world has ended.”

“Yes,” she said. “If you want to be anthropological about it. I’m doing it for them. Can’t you understand that, Rosenberg?”

“Sure. It’s just primate logic.”

“So what about you? What stops you giving up?”

He slouched; it was a shrug, masked by the layers of his suit.

She turned over, to face his huddled back. She reached over his waist and put a gloved hand over his; his glove felt as if it. was empty. “Listen, after eleven years I know you. You back off into generalities and theory whenever anyone gets too close. Tell me why you keep going, Rosenberg.”

At length, reluctantly, he said: “Curiosity. I always wanted to know how it all worked, Paula. It drove me crazy to think that one day I would die, and I’d never see all the science and exploration and discovery that would follow me, all the things people would figure out. And now, here I am on Titan, for God’s sake. A world nobody’s visited before. Every hill we climb offers the prospect of something new, something nobody’s seen. Right now I’m excited.” He smiled at her weakly. “I mean it. I’m looking forward to getting this kerogen, or whatever it is, back to the hab module. Maybe it will keep us alive a little longer. And even if not, it’s something nobody’s seen before.”

“At least you made it this far.”

“Yeah. But—”

“But what?”

“If the Universe is just a puzzle box, it doesn’t mean a damn thing, does it? It’s not enough. Not any more; maybe it never was.”