The tarantula stopped, its front pair of legs feeling the air. Then it turned and walked slowly toward her, each of its legs appearing to move independently of the other seven.

"Yes. I see that it is." Glad there were no visitors to witness her absurdity, Anna stepped aside and gave the magnificent bug a wider berth than science or good sense would've deemed necessary.

Half a mile further down the canyon the walls began to narrow around boulders the size of Volkswagens. Anna scrambled and jumped from one to the next. Middle McKittrick was an excellent place to break an ankle or a neck; join the buzzards' buffet.

The sun slipped lower and the canyon filled with shadow. In the sudden cooling a breeze sprang up, carrying with it a new smell. Not the expected sickly-sweet odor of rotting flesh, but the fresh smell of water, unmistakable in the desert, always startling. One never grew accustomed to miracles. Energized, Anna walked on.

The walls became steeper, towering more than sixty feet above the creek. A rugged hillside of catclaw and agave showed dark above the pale cliffs. The boulders that littered upper McKittrick were no longer in evidence. In the canyon's heart, Anna walked on smooth limestone. Over the ages water had scoured a deep trough, then travertine, percolating out of the solution, lined it with a natural cement.

Not a good place to be caught during the Texas monsoons in July and August. Each time she walked this transect in search of cougar sign, Anna had that same thought. And each time she had the same perverse stab of excitement: hoping one day to see the power and the glory that could roll half a mountain aside as it thundered through.

The smell of water grew stronger and, mixed with the sighing and sawing of the wind, she could hear its delicate music. Potholes began pitting the streambed-signs of recent flooding. Recent in geological time. Far too long to wait for a drink. Some of the scoured pits were thirty feet across and twenty feet deep. A litter of leaves and bones lay at the bottom of the one Anna skirted. An animal-a fawn by the look of one of the intact leg bones-had fallen in and been unable to climb out again.