The borametz trees embodied the first great vegetable revolution since the flowering plants that had arisen in the days before Chicxulub. And in the ages to come — like the initial emergence of plants on land that had enabled animals to leave the sea, like the evolution of the flowering plants, like the rise of the grasses — this new vegetable archetype would have a profound impact on all forms of life.

As she sat on the ground, still panting, watching the mole folks’ baffling behavior, Remembrance heard a familiar soft footstep, an awful hissing breath. She turned her head, slowly, trying to be invisible.

It was the mouse-raptor — the juvenile, the same one that had strayed from its herd of elephant folk to chase her here. It was standing over a line of mole folk who scurried back and forth from tree to planting ground, oblivious to the threat that loomed over them.

It was as if the raptor were taking a small revenge. Few rodents could get through the mighty shells of the borametz nuts. As the borametz spread, the seed-eating stock from which this raptor had sprung — along with birds and other species — would soon be threatened with dwindling food supplies, dwindling ranges — and, in some cases, extinction.

The raptor made its choice. It bent down, balancing with its long tail, and used its delicate front claws to scoop up a bewildered mole woman. The raptor turned her over and stroked her soft belly, almost tenderly.

The mole woman struggled feebly, cut off from the colony for the first time in her life, divorced from its subtle social pressures. It was as if she had suddenly surfaced from an ocean of blood and milk, and she was truly terrified, for the first and last time. Then the raptor’s head descended.

Her companions hurried on past the feet of her killer, their flow barely disturbed.

The mouse-raptor turned, its small ears twitching. And it stared straight at Remembrance.

Without hesitation she plunged straight back into her hole in the ground.

Remembrance stayed in the food chamber for several more days. But she was no longer able to settle back into the exhausted fog that had enveloped her.

In the end it was the madness of the mole folk that drove her out.

Even for this arid area, the season had been dry. The mole folk were having increasing difficulty in finding the roots and tubers on which they relied. The stock in the chamber dwindled steadily, and started to be replaced by other vegetation, like the violet leaves of copper flowers. But this unwelcome diet contained toxic elements. Gradually the poisons built up in the bloodstreams of the mole folk.

At last, everything fell apart.

Again Remembrance was startled awake by a rush of mole folk through the nearly empty food store. But this time they did not move in their orderly columns out through the vents. Instead they swarmed madly, surging up and out of the chamber, shattering its roof in their eagerness to be on the surface.

Remembrance, keeping out of the way of blindly scrabbling claws, followed gingerly. She emerged, this time, into full daylight.

All around her the mole folk swarmed. There were many, many of them, running over the ground, a carpet of squirming bare flesh. The air was full of their milky stink, the scraping of their skins against one another. There were far more than could have come from her own colony: Many hives had emptied as a burst of madness swept through the poisoned, half-intoxicated population.

Already the predators were showing interest. Remembrance saw the stealthy form of a rat-cheetah and a pack of doglike postmice, while overhead birds of prey began their descent. For those who sought flesh this was a miracle, as these little packets of meat just bubbled out of the ground.

It was all a response to the shortage of food. The mole folks’ overcrowded burrows had emptied as they swarmed everywhere in a mindless search for provision. But in their intoxicated state they were unable to keep themselves from danger. Many of this horde would die today, most in the mouths of predators. In the long run it did not matter to the hives. Each colony would retain enough breeding stock to survive. And it wasn’t necessarily a bad thing for their numbers to be reduced in these times of semidrought. Mole folk reproduced quickly, and as soon as the food supply picked up, the empty burrows and chambers would be full again.

The genes would go on: That was all that mattered. Even this periodic madness was part of the grander design. But many small minds would be extinguished today.

As the predators started to feed — as the air filled with the crunch of bone and gristle, the squeals of the dying, the stink of blood — Remembrance slipped away from this place of madness and death, and resumed her long-broken journey toward the distant purple hills.

Remembrance came at last to a great bay, a place where the ocean pushed into the land.

She clambered down exposed sandstone bluffs. Once this area had been under the sea, and sediment had been laid down over millions of years. Now the land had been uplifted, and rivers and streams had cut great gouges in the exposed seabed, revealing deep, dense strata — in some of which, sandwiched between thick layers of sandstone, were embedded traces of shipwrecks and debris from vanished cities.

At last Remembrance reached the beach itself. She scampered along its upper fringe, sticking to the shade of the rocks and scrub grass. The sand was sharp under her feet and knuckles, and got into her fur. This was a young beach, and the sand was still full of jagged edges, too new to have been eroded smooth.

She came to a freshwater stream that trickled down from the rocks toward the beach. Where the water decanted onto the sand, a small stand of trees clung to life. She ducked down and pushed her mouth into the cool water, sucking up great mouthfuls. Then she clambered into the stream itself and scraped the water through her fur, trying to get rid of the sand and fleas and ticks.

That done, she crawled into the shade of the trees. There was no fruit here, but the leaf-strewn floor, cold and damp, harbored many toiling insects that she popped into her mouth.

Before her the sea lapped softly, the water bright in the high sunlight. The sea meant nothing to her, but its distant glimmer had always attracted her, and it was oddly pleasing for her to be here.

In fact the sea had been the savior of her kind.

Torn by great tectonic forces, Africa’s Rift Valley had eventually become a true rift in the fabric of the continent. The sea had invaded, and the whole of eastern Africa had sheared off the mainland and sailed away into what had been the Indian Ocean, there to begin its own destiny. So chthonically slow was this immense process that the mayfly creatures living on this new island had scarcely noticed it happening. And yet, for Remembrance’s kind, it had been crucial.

After the fall of mankind, there had been pockets of survivors left all over the planet. Almost everywhere the competition with the rodents had been too fierce. Only here, on this rifted fragment of Africa, had an accident of geology saved the posthumans, giving them time to find ways to survive the rodents’ ruthless competitive onslaught.

Once this place, East Africa, had been the cradle that had shaped mankind. Now it was the final refuge of man’s last children.

There was something in the water. Cautiously, Remembrance cowered back into the shade.

It was a great black shape, sleek and powerful, swimming purposefully. It seemed to roll, and a fin a little like a bird’s wing was raised into the air. Remembrance made out a bulbous head lifting above the water, with a broad sievelike beak. Water showered from two nostrils set in the top of the beak, sparkling in the air, expelled with a sharp whooshing noise. Then the great body flexed and dove back under the surface. She caught a last glimpse of a tail, and then the creature had vanished. Despite its immense bulk, it left scarcely a ripple in the water.