“I studied the Gaijin on Earth,” Dorothy said. Madeleine could see her smile. “You remember that, on Kefallinia. I got my initial assignment from the Pope… I don’t even know if there is a Pope anymore. The Gaijin have some things in common with us. Sure, they are robotlike creatures, but they are finite, built on about the same scale as we are, and they seem to have at least some individuality. But in spite of their similarity — or maybe because of it — I was immediately overwhelmed by their strangeness. So I was drawn to follow them to the stars, to work with them.”

“And have you discovered yet if a Gaijin has a soul?”

Dorothy didn’t seem offended. “I don’t know if that question has any meaning. Conversely, you see, the Gaijin seem fascinated by our souls. Perhaps they are envious…”

Dorothy stopped dead and held out one hand. Madeleine saw there was some kind of black snow, or a thin rain of dust, settling on the white of her glove palm. “This is carbon,” Dorothy said. “Soot. Just raining out of the air. Remarkable.”

Madeleine supposed it was.

They walked on through the strange exotic air.

Madeleine prompted. “So you traveled with the Gaijin to try to understand.”

“Yes. As I believe Malenfant did.”

“And did you succeed?”

“I don’t think so. What may be more serious,” she said, “is that I don’t think the Gaijin are any closer to finding whatever it is they were seeking.”

They reached the shore of the sea. It was a hard beach, loosely littered with rusty sand and blackened with soot, as if worn away from some offshore seam of coal.

The ocean was very yellow. The liquid was thin, and it seemed to bubble, as if carbonated. Farther out, mist banks hung, dense and heavy. Seeing this garish sea recede to a sharp yellow horizon was eerie.

They stepped forward, letting the liquid lap over their boots. It left a fine gritty scum, and it felt cool, not cold. Vapor sizzled around Madeleine’s feet.

Dorothy dipped a gloved finger into the sea, and data chattered over her visor. “Iron carbonyl,” she murmured. “A compound of iron with carbon monoxide.” She pointed at the vapor. “And that is mostly nickel carbonyl. A lower boiling point than the iron stuff…” She sighed. “Iron compounds, an iron world. On Earth, we used stuff like this in industrial processes, like purifying nickel. Here, you could go swimming in it.”

“I wonder if there is life here.”

“Oh yes,” Dorothy said. “Of course there is life here. Don’t you know where you are?”

Madeleine didn’t reply.

“That’s where the soot and the carbon dioxide comes from,” Dorothy said. “I think there must be some kind of photosynthesis going on, making carbon monoxide. And then the monoxide reacts with itself to make free carbon and carbon dioxide. That reaction releases energy—”

“Which animals can use.”

“Yes.”

“There is life everywhere we look,” Madeleine said.

“Yes. Life seems to be emergent from the very fabric of the universe that contains us, hardwired into physical law. And so, I suppose, mind is emergent too. Emergent monism: a nice label. Though we can scarcely claim understanding…”

They stepped back on the shore and walked farther across the rusty dirt without enthusiasm.

Then they saw movement.

There was something crawling out of the sea. It was like a crab, low and squat, about the size of a coffee table, with a dozen or more spindly legs, and what must be sensors — eyes, ears? — complex little pods on the end of flimsy stalks that waved in the murky air. The whole thing was the color of rust.

And it had a dodecahedral body.

Madeleine could hear it wheezing.

“Lungs,” Dorothy said. “It has lungs. But… look at those slits in the carapace there. Gills, you think?”

“It’s like a lungfish.”

The crab was clumsy, as if it couldn’t see too well, and its limbs slid about over the bone-hard shore. One of those pencil-thin legs caught in a crack and snapped off. That hissing breath became noisier, and it hesitated, waving a stump in the air.

Then the crab moved on, picking its way over the beach, as if searching for something.

Dorothy bent and, fumbling with her gloved fingers, picked up the snapped-off limb. It looked simple: just a hollow tube, a wand. But there was a honeycomb structure to the interior wall. “Strength and lightness,” she said. “And it’s made of iron.” She smiled. “Iron bones. Natural robots. We always thought the Gaijin must have been manufactured, by creatures more or less like us — the first generation of them anyway. It was hard to take seriously the idea of such mechanical beasts evolving naturally. But perhaps that’s what happened…”

“What are you talking about?”

She eyed Madeleine. “You really don’t know where you are? Didn’t the Gaijin tell you?”

Madeleine had an aversion to chatting to Gaijin. She kept her counsel.

“This iron world is Zero-zero-zero-zero, Madeleine,” Dorothy said. “The origin of the Gaijin’s coordinates, the place their own colonization bubble started. The place they came from. No wonder they brought Malenfant here, if they thought he was goingto die.”

Madeleine felt no surprise, no wonder, no curiosity. So what? “But if that’s so, where are they all?”

Dorothy sighed. “I guess the Gaijin are no more immune to the resource wars, and the predatory expansion of others, than we are.”

“Even the Gaijin?” The notion of the powerful, enigmatic, star-spanning Gaijin as victims was deeply chilling.

“If this is a robotic lungfish,” Dorothy said, “maybe life here got pushed back into the oceans by the last wave of visitors. Maybe this brave guy is trying to take back the land, at last.”

The crab thing seemed to have reached its highest point, attained the objective of its strange expedition. It stood there on the rusty beach for long minutes, waving those eyestalks in the air. Madeleine wondered if it even knew they were here. If it recognized the Gaijin as its own remote descendant.

Then it turned and crawled back into the yellow ocean, step by step, descending into that fizzing, smoky liquid with a handful of bubbles.

“The Gaijin are not like us,” Malenfant whispered. He was sitting propped up by cushions in a chair, wrapped in a blanket. He was bird-thin. They had had to bring him back to his own lander; after so long alone he had gotten too used to it, missed it too much. “Cassiopeia is constantly in flux,” he said. “ ‘Cassiopiea’ is just the name I gave her, after all. Her own name for herself is something like a list of catalog numbers for her component parts — with a breakdown for subcomponents — and a paper trail showing their history. A manufacturing record, not really a name. She constantly replaces parts, panels, internal components, switching them back and forth. So her name changes. And so does her identity…”

“Your cells wear out, Malenfant,” Dorothy said gently. “Every few years there is a new you.”

“But not as fast as that. It’s the way they breed, too — if you can call it that. Two or more of them will donate parts, and start assembling them, until you get a whole new Gaijin, who goes off to the storeroom to get the pieces to finish herself off. A whole new person. Now, where does she come from?” He sighed. “They have continuity of memory, consciousness, but identity is fluid for them: You can divide it forever, or even mix it up. You see it when they debate. There’s no persuasion, no argument. They just… merge… and make a decision. But the Gaijin are cautious,” he said slowly. “They are rational; they consider every side of every argument; they sometimes seem paralyzed by indecision.”

“Like Balaam’s ass,” Dorothy said, smiling. “Couldn’t decide between two identical bales of hay.”