She stands near the outer wall of the parapet, looking out over the great river valley where their children once played—and were trained by the Ur-Didact. Pleasant and now intensely painful memories. Most of her life has been centered on this world.

“We may never return,” she says. “All of this…”

She cannot complete her thoughts. She flees from the parapet, leaving the machines to finish their final tasks.

* * *

The IsoDidact does not stop at preparing Audacity for departure. He orders the ship to pass over the far side of the planet. Catalog is with him; two parts of the triad are with the Librarian.

But the Ur-Didact is alone, on a continent set aside for primitive life-forms, its quietness, until now, undisturbed. The IsoDidact surveys the continent from space, then makes inquiries of a local tectonics monitor. The monitor is sluggish, preparing to power down for the long sleep this world will soon endure. But there has been no impact, of that it is certain.

The IsoDidact finds his original on a long, sinuous island of ancient basalt. Great expanses of wort and moss and slime-molds flourish here, bathed in creeping mists, on the edges of a shallow sea where bacterial nodules and mats compete with stalk-rooted, pillow-frond forests; where the most primary, first-form animals creep through waters now lit by day and warmed by the sun, while night has returned to the river valley.

Here also is the only Precursor artifact on the entire planet, a circular, temple-like structure of no apparent purpose, perhaps half a billion years old. It is so small that only the most complete listings mention it. It consists of a ring of blunt, rounded towers rising from a flat and featureless base, mottled gray and white, covered in places by blankets of moss, though they draw no sustenance from its impassive surface.

While immobile and eternal, as all Precursor structures were, until now, this one has no apparent purpose; perhaps it once served as a kind of marker, a testimonial to a far-ranging expedition, or the foundation of some other structure long removed or decayed.

The IsoDidact descends in a seeker and lands nearby. The Ur-Didact ignores the interruption, plodding through shallow, brackish ponds, toward the ring of towers, under the flowing and ever-present mist, an intruder in the peace. He squats before the artifact, clasping and unclasping his hands.

His duplicate approaches across a low, mossy glade.

The Ur-Didact acknowledges his presence. “Humans would have prayed to this,” he says. “Everywhere they found powers and forces, in oceans and rivers, in trees, in animals—even in rocks. Forerunners pray their sorts of prayers only to the Mantle. Who, then, is more deserving?”

“Why have you come here?” the IsoDidact asks.

“When we first met, Bornstellar, you were looking for treasure. Perhaps it’s here and we never recognized it.”

“Nothing’s changed here. We should return now.”