More gravel and sand was building up around them, and then suddenly they were on top of the avalanche they had created. The friction of the terrorist’s battered body scratching against the ground vanished without warning, and their speed seemed to double. Juan could no longer control their slide. When the gully began to twist to the left, the sheer volume of material rocketing down the hillside could no longer be contained and burst from its banks like a river in flood, bearing Juan and the Arab with it. They caught air as the ground dropped sharply away. When they came down, the terrorist was no longer screaming, and they had gained a few precious yards on the wall of gravel now in pursuit.

This new valley was wider and deeper than the first but twisted more often. Again, the avalanche caught up to them and again Juan rode the man as though he were straddling a tree trunk in a logging flume. Just ahead, he could see the debris cascading off the shelf he’d spotted from the top. He chanced a look up the slope. Behind the shifting thrust of gravel and sand, boulders tumbled in the avalanche, succumbing to the forces of gravity and the weight of dirt from above. It was like looking into the grinding mouth of an industrial wood chipper. The boulders banged and rattled against one another, pulverizing themselves as they fell.

He looked back downslope. The avalanche arced ten feet through space beyond the cliff before cascading to earth. Had it been water, Juan would have gone over the falls and had a good chance of swimming away at the bottom. But not here.

Cabrillo dug his prosthesis into the gravel, forcing it down into the avalanche until he felt solid ground beneath. Seconds before he and the Arab were carried over the precipice, he pushed off with everything he had, launching himself off the terrorist’s corpse in an awkward lurch that carried him right to the edge of the avalanche.

He scrambled onto all fours and started clawing his way upward, fighting the remorseless downward plummet of the gravel under him. It was like crawling against a treadmill set on maximum. There was no way he could gain any ground. The avalanche was much too fast. He only hoped to buy himself a few precious seconds as he angled himself farther up the side of the gully, driving himself to get out of the landslide’s grasp before it carried him over the cliff.

With ten feet to go, he was still mired in the fringes of avalanche. His bloodied fingers dug into it with machinelike tenacity, and his legs pistoned, kicking up dirt with each thrust. But it wasn’t enough. He was too far from the slide’s boundary to haul himself clear.

It wasn’t in him to give up, and he made one last supreme effort. The cascade of loose debris claimed the shattered remains of his companion at the same instant his fingers felt solid ground. Cabrillo groped to find purchase, and his hands clasped something hard and round. With no choice, he grasped it in his left hand and swung to find purchase with his right.

He knew the first rule of rock climbing was never to trust vegetation. It could let go without a moment’s notice. But with no other choice, he clung to the root of a gnarled tree left exposed to the sun.

Almost immediately, the root started to tear away from the earth as if he had yanked on the end of a rope that had been buried just beneath the surface. Though he had managed to drag all but his feet free of the landslide, he was relying entirely on the root, and the more its tangled subterranean connections snapped, the more he fell toward the edge of the cliff.

His legs went over the edge, and then his hips. He held on to the root with everything he had while less than a foot away a continuous torrent of sand and rock plummeted past his shoulder. His fall checked for an instant, he tried to pull himself upward, only to have more of the root break away. He slipped completely over the edge, dangling by his arms. Just before he went over, he saw that the wall of boulders and rocks was seconds away from cascading over the falls.

He forced himself to crab along the cliff face to his right, his head and shoulders pounded by the light rubble, lengthening the angle between himself and where the root was anchored on the side of the gulley. Then he raced back, running through the deluge seconds ahead of the boulders. He burst from the landslide, swinging like a pendulum. He reached out with his left hand and just managed to grasp a knuckle of rock in his fist.

His movements scraped the root against the razor-sharp edge of the cliff, like a length of string against a saw blade. Cabrillo had no time to gain a better purchase on the piece of sandstone in his hand when the root parted. His body crashed into the cliff. The tree root that had saved his life tumbled away, swallowed by the debris pouring down the mountainside.

Hanging by only one hand, he looked down in desperation. At first, the cliff appeared to be as smooth as a pane of glass and as perfectly vertical as the side of a skyscraper. But just a couple of inches below his feet was a shelf no wider than a paperback book.

The friable sandstone knuckle he was holding started to come apart in his grip.

Juan gathered a breath and let himself drop. There wasn’t enough room to absorb the shock by bending his knees, and he could feel the void sucking at his heels. The satellite phone, which had stayed with him for his wild plummet, was dislodged by the impact, snaking down one pant leg and emerging from the cuff. There was nothing he could do when it clattered off the shelf and disappeared into the valley below.

He couldn’t hear it land over the din of falling debris, but he knew it was a total loss. He clutched at the cliff face. The stone was warm on his cheek.

Next to him, curtains of dust rose from the rock and sand falling over the cliff, but already the landslide was slowing. With the steady wind swirling around the mountaintop, it wouldn’t be long before the dust blew away, exposing Cabrillo to anyone observing from above. The vertical drop to the next part of the mountain slope was at least thirty feet, with an additional hundred of steep terrain to the valley floor.

He looked to his right. The avalanche was almost over. The largest of the boulders now littered the ground below while only a thin trickle of sand poured over the edge of the cliff.

The second rule of climbing was never descend a rock face unless you know the route.

Juan had no idea what lay below him, what handholds and toe-holds he would find, but with twenty armed gunmen doubtless peering down the hill to see what had happened to their comrades the rules of safe climbing weren’t particularly relevant.

He bent down as far as he dared and lowered a leg off the shelf, feeling with his toes for some kind of hold. He also locked the ankle joint of his artificial leg. His foot found a slight depression, barely big enough for all his toes, but it was enough to take his weight. He lowered himself farther still, so that his elbows rested on the narrow shelf. He switched feet in the little niche and again poked blindly for another irregularity in the rock. There was nothing to be felt. The stone was featureless.

A thick tangle of rope suddenly shot past his face, uncoiling as it fell. Looking up, he saw that the cliff hid him from the terrorists above. They weren’t throwing him a lifeline, he realized, they were going to send someone down to check on survivors. It was just his good luck that they had chosen to send the climber exactly where he was clinging to the stone.

Juan quickly climbed back onto his shelf and carefully pulled off his boot. He yanked free some buttons of his uniform shirt and stuffed the boot against his chest. Then he wrapped the rope around the smooth molded foot of his prosthesis, looping it twice around, almost like the artificial limb was a pulley. He started to feel the rope dance and jerk in time with the movements of the man who had volunteered to check on his fallen teammates. Cabrillo grasped a handful of the line dangling over the void and stepped into empty space. With his back against the rock face, he slowly paid out rope through his hands. Because of the loops of rope around his foot and his locked ankle, he lowered himself down the cliff hand over hand, so smoothly that the guy above never felt him on the line.