Thea's world was the Mantle of the Star, an immense cavern of yellow-white Air bounded above by the Crust and below by the Quantum Sea. The Crust itself was a rich, matted ceiling, purple-streaked with krypton grass and the graceful curves of tree trunks. Far below Thea, the Sea formed a floor to the world, mist-shrouded and indistinct. All around her, filling 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 the far upflux -- the North -- and arced past her like the trajectories of immense, graceful animals, converging at last into the soft red blur that was the South Pole, millions of mansheights away.

Thea's people lived at the lower, leafy fringe of the Crust forest. Their cocoons were suspended from the trees' outer branches, soft forms among the shiny, neutrino-opaque leaves; and as the humans emerged they looked -- Thea thought with a contempt that surprised her -- like bizarre animals: metamorphosing creatures of the forest, not human at all. But the cries of children, the frightened, angry shouts of adults, were far too human... The tribe's small herd of Air-pigs, too, were squealing in unison, thrashing inside the loose net that bound them together, and staining the Air green with their jetfarts.

But where was the danger?

She held her fingers up before her face, trying to judge the spacing and pattern of the vortex lines. Were they drifting, becoming unstable?

Twice already in Thea's short life, the Star had been struck by Glitches -- starquakes. During a Glitch, the vortex lines would come sliding up through the Air, infinite and deadly, scything through the soft matter of the Crust forest -- and humans, and their belongings -- as if they were no more substantial than spoiled Air-pig meat...

But today the lines of quantized spin looked stable: only the regular cycles of bunching which humans used to count their time marred the lines' stately progress.

Then what? A spin-spider, perhaps? But spiders lived in the open Air, building their webs across the vortex lines; they wouldn't venture into the forest.

She saw Lur, now; her sister was trying to Wave towards her, obviously panicking, her limbs uncoordinated, thrashing at the Magfield. Lur was pointing past Thea, still shouting something--

There was a breath of Air at Thea's back. A faint shadow.

She shifted her head to the right, feeling the lip of her cocoon scratch her bare skin.

A ray, no more than two mansheights away, slid softly towards her.

Thea froze. Rays were among the forest's deadliest predators. She couldn't possibly get out of the cocoon and away in time -- her only hope was to stay still and pray that the ray didn't notice she was here...