But as he sat studying them he noticed other things. The thorns were savagely long. Their leaves had a strange look to them, green on one side, a dull gray on the other, veinless and as blank as paper. Their limbs did not curve with the natural lines of most acacias. Instead they bent like the joints of age-twisted fingers, with bulbous knuckles. Though he had commented on the trees when he first saw them, the more he sat near them, the more he wished to be up and moving. Shen, he felt, should not look too closely at them.

The next day they dropped into a lush valley crowded with trees and long-grassed meadows. Marshy ponds spotted the flat areas, connected by a web of streams. It was an eerily silent place, just the burble of water in the air. That was it. No insects or animal calls, no sign of life at all. Unnatural.

Barely had he formed the thought when Shen called out, as if in direct refutation of it, “Look, birds!”

A flock appeared from behind them, thousands of them, a mass of black darts that cut into the air, rising straight into the sky. They turned as one and carved a rough circle in the air above. They moved faster than any birds Kelis had ever seen, their wings tight at their sides and not, as far as he could tell, flapping at all. They looked to be in a great rush. Soundless save their motion through the air, they cut away and dropped over the far edge of the valley.

“Come on!” Shen called, tugging her mother forward. “We should follow them.”

As they walked through the valley and rose at the far end of it, Kelis had the most vivid sensation yet of feeling the mountains move around them. The rate of their strides did not match the speed with which even the distant peaks slipped away behind them. He even paused to look back and still felt the sensation of moving. Just the sensation, not actual evidence of something amiss. He darted his eyes from one area to another, as if he would catch the mountains in the act and shame them. He never quite managed it.

When he rejoined the others, he found them studying something on the ground: a bird, black as a raven but with an insect catcher’s small frame and beak, dead—its neck snapped, apparently from impact with the ground. Benabe warned Shen not to touch it, but the girl showed no sign she intended to. They all stood staring for a time. Not too long, for the more they looked, the less the bird seemed like a bird. Kelis was sure its wings had been fixed in position, stiff as the gliders he had carved from wood as a boy. Its eyes were blue, the exact color of sky and so striking against the dead black of its plumage.