She gazed around, sniffing the photons.

Dura’s world was the Mantle of the Star, an immense cavern of yellow-white Air bounded below by the Quantum Sea and above by the Crust.

The Crust itself was a rich, matted ceiling, purple-streaked with grass and the hairlike lines of tree trunks. By squinting — distorting the parabolic retinas of her eyes — she could make out dark motes scattered among the roots of the trees fixed to the underside of the Crust. Perhaps they were rays, or a herd of wild Air-pigs, or some other grazing creatures. It was too distant to see clearly, but the amphibian animals seemed to be swirling around each other, colliding, confused; she almost imagined she could hear the cool sound of their distress.

Far below her, the Quantum Sea formed a purple-dark floor to the world. The Sea was mist-shrouded, its surface indistinct and deadly. The Sea itself, she saw with relief, was undisturbed by the Glitch. Only once in Dura’s memory had there been a Glitch severe enough to cause a Seaquake. She shuddered like the Magfield as she remembered that ghastly time; she had been no older than Farr, she supposed, when the neutrino founts had come, sweeping half the Human Beings — including Phir, Dura’s mother and Logue’s first wife — away and on, screaming, into the mysteries beyond the Crust.

All around her, filing the Air between Crust and Sea, the vortex lines were an electric-blue cage. The lines filled space in a hexagonal array, spaced about ten mansheights apart; they swept around the Star from far upflux — from the North — arced past her like the trajectories of immense, graceful animals, and converged into the red-soft blur that was the South Pole, millions of mansheights away.

She held her fingers up before her face, trying to judge the spacing and pattern of the lines.