“Mother—”

“You understand all that, of course.” She grimaced, her masklike face twisting. “You know, the fate of the old is to turn into one’s own parents; this is just the way my mother used to speak to me. No conversation that didn’t turn into a lecture.”

They pulled into the shore by a shallow beach. The launch grounded itself, and Lucy hopped out, her sandaled feet crunching on the coarse black sand. She turned back to help her mother, and then the two of them made the launch fast and briskly hauled out their gear.

As Joan began to set up the traps, Lucy took a couple of the hypo rifles and went patrolling along the beach.

The beach itself was an eerie place. The black lava sand was littered by equally black rocks. Even the sea was made to look black, like a sea of oil, by the darkness of its bed. In the distance she could make out mangrove, trees capable of exploiting the salty water, a splash of green against the mineral black and red.

And marine iguanas were lined up here like fat meter-long sculptures, their expressionless faces turned to the sun. They were themselves black, so dark and still it took a second glance to recognize them as living things and not an eerie formation of rope lava. Stranded here on Darwin’s laboratory after rafting across with tortoises and turtles, the iguanas’ ancestors had been dry-land creatures, tree climbers. They were gradually adapting to living off algae they strained out of seawater. But they would spit out the excess water — the air was filled with their hawking; the little jets spouting from their mouths sparkled in the sunlight — and they had to rely on the heat of the sun to bake the thin repast in their stomachs.

Lucy kept her rifle ready. If feral kids were around, it paid to be wary.

During the scramble for places on the last few boats back to the mainland, kids had been dumped here by desperate parents. The weak ones had quickly died, leaving their bones to litter the beaches and rocky outcrops, like the bones of sea lions and iguanas and albatrosses. But some of the kids had survived. In fact the word “kids” was a misnomer, for they had already been here long enough to spawn a second generation, children who had grown up knowing nothing but these barren bits of rock and the endless oceans, kids even more wordless and without culture than their parents. Feral kids, without tools, with only a rudimentary language — and yet human, capable of being cleaned up and educated.

And also capable of taking a bite out of your leg.

Joan’s traps were simple: nothing much more than concealed nets and snares, baited with rich-smelling spicy food. When she had set them up, she and Lucy settled down out of sight in the shade of an outcrop of tuff — crumbling, easily eroded lava — and prepared to wait for the feral children.

Since Rabaul, life had been hard for Joan and her daughter — but then it had been hard for everyone on the planet. Even though her grand empathetic project had been crushed, Joan hadn’t stopped working. With wide-eyed little Lucy in tow, she had retreated here, to Galapagos.

Paradoxically these fragile islands had been relatively well preserved through the greater global catastrophe. Once seventeen thousand people had lived here, mostly emigrants from mainland Ecuador. Before Rabaul there had been a constant friction between the needs of this growing, resentful population and the unique wildlife, nominally preserved by Ecuador’s national park legislation. But the islands had always been fed by the mainland. When everything had spun apart after Rabaul, when the ships had stopped coming, most of that population had fled back home.

So the islands, largely free of people — and their companions, the rats and the goats, and their waste products, sewage and oil — had, in their modest way, begun to prosper again.

Joan and Lucy — and a handful of others, including Alyce Sigurdardottir until her death — had settled in the ruins of what had once been the Charles Darwin Research Station on Santa Cruz, and, with the locals who remained, had devoted themselves to helping the creatures that had so intrigued Darwin himself through the unfolding extinction.

For a time there had been communications. But then the high-altitude electronics-busting bombs, fired off at the height of the messy multipolar wars, had wrecked the ionosphere. And when the last satellites were shot out of the sky, that had been the end of TV, even speech radio. Joan had long maintained a regime of listening, as long as their sets and power lasted. But it had been years since they had heard anything.

No radio, then. No contrails in the sky, no ships on the horizon. There was no outside world, for all intents and purposes.

They were getting used to the isolation. You always had to remember that when something wore out it was gone forever. But the supplies left behind by those vanished thousands — tools and clothing and batteries and torches and paper and even canned foods — would sustain this little community of fewer than a hundred for their lifetimes and beyond.

The world might be ending — but not here, not yet.

Humanity had not vanished; of course not. The great terminal drama that was unfolding around the planet had many years, even decades to run yet. But sometimes, when Joan thought about the very long run, she realized she could see nothing ahead for Lucy, still just eighteen, and her children after her; none at all. So, mostly, she didn’t think about it. What else was there to do?

At Lucy’s feet, crabs scuttled across the rocks, brilliant red against the black surface, with stalk-mounted sky-blue eyes.

“Mom—”

“Yes, dear?”

“Do you ever wonder if we’re doing the right thing for these kids? I mean, what if the grandparents of those marine iguanas had said, ‘No, you can’t eat that gloopy sea stuff. Get back up the trees where you belong.’ ”

Joan’s eyes were closed. “We should let the kids evolve, like the iguanas?”

“Well, maybe—”

“In order for the descendants of a handful of the kids to adapt, most of those alive now would have to die. I’m afraid we humans don’t have the moral capacity to sit back and let that happen. But if the day comes when we can’t help them, well, that’s when Papa Darwin takes over.” Joan shrugged. “Adapt they would, that’s for sure. But the result might not be very much like us. To survive here, the cormorants have lost flight, perhaps the most beautiful gift of all. I wonder what would be taken from us. Of course that’s just my prejudice. Isn’t it a wonderful thought to imagine that however cruel the process of evolution might seem to us, something new and in some senses better than us might some day come out of it?”

Lucy shuddered, despite the heat. “That’s scary.”

Joan tapped Lucy’s leg. “Scared is good. It shows you are starting to use your imagination. The implications of who we are and how we got here — sometimes it scares me, even now.”

Lucy clutched her hand. “Mother, I have to say this. Your view of life is so godless.”

Joan drew back a little. “Ah. I knew this day would come. So you’ve discovered the great Ju-Ju in the sky.”

Lucy felt unreasonably defensive. “You’re the one who has always encouraged me to read. I just find it hard to believe God is nothing but an anthropomorphic construct. Or that the world is just a… a vast machine, churning through our tiny lives, morphing our children like a handful of algae in a dish.”

“Well, maybe there is still room for a God. But what kind of God would intervene the whole time? And isn’t the story wonderful enough on its own?

“Look at this way. Think about your grandmothers. You have many ancestors in each generation, but only one maternal grandmother. So there is a molecular chain of heredity, leading from each of us into the deepest past, as far as we can see. You have ten million grandmothers, Lucy. Since that comet wiped out the dinosaurs and gave those first little ratty primates a chance, ten million. Imagine if they were all lined up, side by side, your grandmother beside her own mother, and then hers in turn.