...But, of course, that wasn't possible; for their children had been taken from them, by well-meaning Dura, and transported to the South Pole. When he stared into the dull crimson glow of the Pole, in the far downflux, Mur felt as if a chain as long as a vortex line connected him directly to his child, a chain which dragged inexorably at his heart. Dura's action had surely been in the best interests of the children. But it left Mur knowing that his only chance of meeting his son again was to stay alive and to complete this trek, all the way to the City at the Pole.

He squeezed Dia once, and then they broke and prepared to return to the Crust-forest, to face the others and begin the day's work.

"Dia! Mur!" The voice, drifting down from the Crust-forest, radiated excitement.

Dia and Mur slowed their ascent, confused, and looked up. Philas was dropping toward them, her skinny legs pumping at the Air. When she reached the couple, she grabbed at their arms to stop herself.

Dia held Philas's shoulders. "What is it? What's wrong?"

Philas, panting, the bones of her face prominent under her tied-back hair, shook her head. "Nothing's wrong. But... look. Look down there." She pointed, down past their feet into the Mantle.

The three of them separated and tipped forward in the Air. Mur peered down, trying to follow the direction of Philas's gesture. He saw the orderly array of vortex lines, the dull purple bruise of the Quantum Sea beyond the crystalline Air. There seemed nothing unusual, except...

There. A small, dark knot in the Air, a hint of motion.

He turned to Dia. "Your eyes are sharper than mine. What is it?"

"People," she said, squinting down. "A group of them. Twenty or thirty, maybe. It looks like an encampment. But there's something at the center..."

"What?"

Philas thrust her face forward at Dia. "Do you see it?"

"I think so," Dia said slowly. Her eyes narrowed. "But it might not mean anything. Philas..."

Mur was baffled. "What is it? What do you see?"

Uncertainty and fear creased Dia's small, pretty face. "It's a tetrahedron," she said.

—

The fifteen Human Beings gathered on the lower edge of the forest and debated what to do. Dia, fearful, uncertain, thought they shouldn't waste time on this chance encounter; she wanted simply to continue with the slog to the Pole. Mur sympathized. The Human Beings were already divided, listless, growing steadily more apathetic. It was becoming ever harder to maintain the momentum of this trek across the Mantle; and once that momentum was gone, it might be impossible to regain.

They would be stranded, wherever they stopped. And that, of course, would be unbearable for those with children at the Pole.