“Make the pile on the south side of each trench. It’ll help shade us.”

Eight inches down he came on the face of a boulder and wanted to shriek out his frustration. He tried to dig around it but it seemed to have no end. He had to move ten feet away and start again.

The crumpled folds of the mountains that ringed the horizons began to turn blue with shadow. A drop of sweat dripped from his nose onto the back of his hand. He forced himself to relax, slow down, dig with less effort. He remembered a time when he had been lost in the mountains and happy to be lost: he’d had a backpack and a canteen of water and no place in particular to go.

The earnest task occupied his attention and freed him from the obligation to think ahead. It took all his concentration to shape the trench. Keep the walls vertical. Dig carefully around each rock—some of them were the size of a man’s head and weighed seventy-five pounds—and lift it out and place it on the rim of the dig to absorb and deflect the sun.

He worked slowly, on his knees, right hand steadily lifting and falling like the arm of a steam hammer. Break up a layer of clay and lift it out a cupped double-handful at a time. Pack it down on the rim. Lift another. He made rakes of his fingers.

But the thought of water came relentlessly into his mind. What good was it to postpone death a few hours if there were no solution to the second question?

There was a little cactus. Staghorn cholla mostly. No water in that; it was as spindly as rib bones. In the late afternoon when the heat waned they would have to make an expedition in search of fat varieties of cactus: the barrel, the jumper, even the prickly pear could be mashed to pulp for liquid. But he doubted there’d be enough to sustain them for more than a day before they’d cleared this area of moisture-bearing cactus: he doubted there was more than one clump in each quarter acre.

Underground water? No—not within reach of the surface; otherwise there’d have been deciduous trees. He tried to remember the signs: obviously a cottonwood or sycamore meant water close to the surface; but he’d seen none.

The light strengthened. He examined the country.

It was a surrealist landscape. Spotted scrub writhed on the bare tan-yellow plain. The ground was desolated by drought, naked and barren. A few miles away in any direction lilac hills undulated toward mountains that loomed in tilted tiers of gray and blue and cayenne red.

The most common growth he saw was creosote: greasewood bushes with their leaves dark oily green. He remembered desert horseback trips, his father taking him out of Chinle for camping and hunting weekends. A horse wouldn’t eat greasewood. It suggested poison.

Keep it in mind.

He saw tall spindly fans of ocotillo. Nothing there but solid dry stalks of brittle wood clothed in spines.

The little hat-sized clumps looked like sagebrush but they weren’t. Saltbush, he recalled; you could tell by the yellowish-green color—it didn’t have the pastel blue hue of sage.

Twenty yards down the slope he could make out a manzanita shrub by its gnarled red bark. More of them farther out along the desert. No help there either.

Catclaw everywhere: the weed of the desert. A bush in size and shape. No nourishment or moisture in it.

Grass in odd spotted clumps: sometimes a single blade of it, sometimes a bouquet. The tips had gone to tufted wheatlike seed pods. Yellow and dry.

Maguey—the century plant. Tall stalk, sunflower top. Blades around its base like a palm tree. The Mexicans made beer and liquor out of the maguey. Might get moisture by pulping it. Worth a try anyway. He saw six of them within walking distance.

He counted nine jumping-cholla clumps in a hundred-yard circle. There was one barrel cactus higher along the hill; it looked skinny—they only fattened after a heavy rain—but it was the nearest thing to a life-saving supply of water he could see within reach. That would be the first target.

The Senita would be next. It was an organ-pipe cactus only about two feet tall but fleshier than most varieties.

It meant they were definitely in Arizona; the Senita grew throughout northern Mexico but in the United States it was found only in Arizona near the border. They weren’t in Mexico; they’d neither crossed at a border station nor cut their way through a fence.

All the while he kept digging. The sun appeared.

A breeze, much hotter than before, raked him with its sinister caress. He began digging the second trench. Jay was helping Shirley at the fourth dig. Mackenzie scraped the chalky topsoil away and began to cut into the earth with his stone. His fingernails were cracked; blood had congealed on one thumb.

The sun began to flush him; it drew the sweat out of him. A sense of urgency quickened his breath. He had to fight it down.

Toward the east the earth glittered as if perspiring: mica particles, pyrites, quartz in the rocks picking up the sun’s reflection. A small lizard darted toward shade.

Under his hair the scalp prickled with sweat. He stopped work and returned to his first trench and lay in it to cool off. The earth around him was damp and thick with a musty redolence. He watched the sky—cloudless, pale. A bird passed high overhead with a steady slow wingbeat.

After a few minutes he crossed the twenty feet to the slope where Jay and Shirley were digging. The hole was more than two feet deep. All he could see was their heads and shoulders until he was up close: they’d built up the parapet.

He interrupted. “Jay can finish this. Have a look at Earle’s leg, will you?”

He saw she was trembling. Exhaustion, fear, hopelessness. He gave her a hand up. Jay looked up at him, wearing an expression of black fury.

Mackenzie watched Shirley pick her way toward Earle Dana, who had not moved in the past hour.

Jay grunted with the effort of lifting a stone out of, the pit. “I don’t know what good it’ll do her looking at his leg.”

“She’s the only one among us who’s used her M.D.”

“He needs splinting, right? We haven’t even got the equipment to splint him. Sticks, sure, we can break off sticks—but what do we tie them with?”

“Shirley’s hair.”

Jay gaped at him. “My God.”

“You’d better lay off down there—that looks deep enough.”

Jay sat back weakly against the wall of the pit. The sun only reached his face. His hairy legs were as spindly as a colt’s: you could see every bone. He had no fat to live on.

Something glittered in the corner of Mackenzie’s vision. At first he disregarded it, taking it for another bit of desert glare. Then he turned and had a better look. He moved off.

“Where are you going?”

“Brass collecting.”

“What?”

He walked slowly, picking spots for his feet. What time was it anyway? Six? Half past six? The sun was three diameters above the horizon. This early it wouldn’t burn the skin badly. He kept walking toward the dazzling yellow reflection, searching to either side of it for more metal.

They’d come tumbling out of the sky, falling ten thousand feet or more, and they’d spread themselves out in an uneven row across the desert—two shells quite close together, then forty yards away another and far beyond that he saw the glimmer of yet another.

He picked up the two at his feet. They’d be enough for the time being; he didn’t use the energy to walk farther. He turned and went back up the slope.

Thirty-caliber aerial machine-gun shells. No telling how long they’d been out here. Everything was metric nowadays: millimeters.

“What the hell good are those supposed to do us?”

“We’ve just moved from the Stone Age into the Bronze Age.”

He kept the shells in his hand and walked right past Jay across the slope to where Earle lay asprawl with his mouth open and his eyes shut. Shirley looked up. “It’s shock. I think. He’s still chilled—you can see the goose bumps.”