AUGUST 7, 8:32 PM.

AMAZON JUNGLE

Kelly stood off from the others, trying her best to assimilate the news her mother had reported. She stared out into the jungle, serenaded by the end-less chorus of locusts and river frogs. Firelight failed to penetrate more than a few yards into the shadowed depths of the forest. Beyond the glow, the jungle hid its mysteries.

Closer at hand, a group of Rangers knelt, setting up the camp's perimeter motion-sensor system. The laser grid, rigged a few feet off the ground and established between the jungle and the camp, was meant to keep any large predator from wandering too near without being detected.

Kelly stared beyond their labors to the dark forest.

What had happened to Agent Clark out there?

A voice spoke near her shoulder, startling her. "Gruesome news indeed."

Kelly glanced over and found Professor Kouwe standing quietly at her side. How long had he been there? Clearly the shaman had not lost his innate abilities to move noiselessly across the forest floor. "Y . . . Yes," she stammered. "Very disturbing:"

Kouwe slipped out his pipe and began stoking it with tobacco, then lit it with a fiery flourish. The pungent odor of smoky tobacco welled around them. "And what of your mother's belief that the cancers and the regenerated arm might be connected?"

"It's intriguing . . . and perhaps not without merit:"

"How so?"

Kelly rubbed the bridge of her nose and gathered her thoughts. "Before I left the States to come here, I did a literature search on the subject of regeneration. I figured it might better prepare me for anything we find."

"Hmm . . . very wise. When it comes to the jungle, preparation and knowledge can mean the difference between life and death:'

Kelly nodded and continued with her thoughts, glad to express them aloud and bounce them off someone else. "While conducting this research, I came across an interesting article in the Proceedings of the National Academy of Sciences. Back in 1999, a research team in Philadelphia raised a group of mice with damaged immune systems. The mice were to be used as a model to study multiple sclerosis and AIDS. But as they began working with the immune-compromised creatures, an odd and unexpected phenomenon developed:"

Kouwe turned to her, one eyebrow raised. "And what was that?"

"The researchers had punched holes in the mice's ears, a common way of marking test animals, and discovered that the holes healed amazingly fast, leaving no trace of a wound. They had not just scarred over, but had regenerated cartilage, skin, blood vessels, even nerves:" Kelly let this news sink in, then continued. "After this discovery, the lead researcher, Dr. Ellen Heber-Katz, tried a few experiments. She amputated a few mice's tails, and they grew back. She severed optic nerves, and they healed. Even the excision of a section of spinal cord grew back in less than a month. Such phenomenal regeneration had never been seen in mammals:"

Kouwe removed his pipe, his eyes wide. "So what was causing it?"

Kelly shook her head. "The only difference between these healing mice and ordinary mice was their defective immune systems:"

"And the significance?"

Kelly suppressed a grin, warming to the subject, especially with such an astute audience. "From the study of animals with the proven ability to regenerate limbs-starfish, amphibians, and reptiles-we do know their immune systems are rudimentary at best. Therefore, Dr. Heber-Katz hypothesized that eons ago, mammals made an evolutionary trade-off. To defend against cancers, we relinquished the ability to regenerate bodily limbs. You see, our complex immune systems are designed specifically to eliminate inappropriate cell proliferation, like cancers. Which is beneficial, of course, but at the same time, such immune systems would also block a body's attempt to regenerate a limb. It would treat the proliferation of poorly differentiated cells necessary to grow a new arm as cancerous and eliminate it:"

"So the complexity of our immune systems both protect and damn us:"

Kelly narrowed her eyes as she concentrated. "Unless something can safely turn off the immune system. Like in those mice:"

"Or like in Gerald Clark?" Kouwe eyed her. "You're suggesting some-thing turned off his immune system so he was able to regenerate his arm, but this phenomenon also allowed multiple cancers to sprout throughout his body."

"Perhaps. But it has to be more complicated than that. What's the mechanism? Why did all the cancers arise so suddenly?" She shook her head. "And more important, what could trigger such a change?"

Kouwe nodded toward the dark jungle. "If such a trigger exists, it might be found out there. Currently three-quarters of all anticancer drugs in use today are derived from rain forest plants. So why not one plant that does the opposite-one that causes cancer?"

"A carcinogen?"

"Yes, but one with beneficial side effects . . . like regeneration:"

"It seems improbable, but considering Agent Clark's state, anything might be possible. Over the next few days, at my request, the MEDEA researchers will be investigating the status of Gerald Clark's immune sys-tem and examining his cancers more closely. Maybe they'll come up with something:"

Kouwe blew out a long stream of smoke. "Whatever the ultimate answer is, it won't come from a lab. Of that I'm certain:"

"Then from where?"

Instead of answering, Kouwe simply pointed the glowing bowl of his pipe toward the dark forest.

Hours later, deeper in the forest, the naked figure crouched motionless in the murk of the jungle, just beyond the reach of the firelight. His slender body had been painted with a mix of ash and meh-nu fruit, staining his skin in a complex pattern of blues and blacks, turning him into a living shadow.

Ever since first dark, he had been spying upon these outsiders. Patience had been taught to him by the jungle. All teshari-rin, tribal trackers, knew success depended less on one's actions than on the silence between one's steps.

He maintained his post throughout the night, a dark sentinel upon the camp. As he crouched, he studied the giant men, stinking with their foreignness, while they circled around and around the site. They spoke in strange tongues and bore clothing most odd.

Still, he watched, spying, learning of his enemy.

At one point, a cricket crawled across the back of his hand as his palm rested in the dirt. One eye watched the camp, while the other watched the small insect scratch its hind legs together, a whisper of characteristic cricket song.

A promise of dawn.

He dared wait no longer. He had learned all he could. He rose smoothly to his feet, the motion so swift and silent that the cricket remained on the back of his steady hand, still playing its last song of the night. He raised the hand to his lips and blew the surprised insect from its perch.

With a final glance to the camp, he fled away into the jungle. He had been trained to run the forest paths without disturbing a single leaf. None would know he had passed.

Moreover, the tracker knew his ultimate duty.

Death must come to all but the Chosen.

CHAPTER SIX

The Amazon Factor

AUGUST 1 1, 3:12 !?M.

AMAZON JUNGLE

Nate kept one finger fixed to his shotgun's trigger, the muzzle pointed ahead. The caiman had to be almost twenty feet long. It was a huge specimen of Melanosuchus niger, the black caiman, the king of the giant crocodilian predators of the Amazon rivers. It lay atop the muddy bank, sunning in the midafternoon heat. Black armored scales shone dully. Its maw gaped slightly open. Jagged yellow teeth, longer than Nate's own palm, lined the cavity. Its bulging, ridged eyes were solid black, cold and dead, the eyes of a prehistoric monster. Stone still, it was impossible to tell if the great beast even acknowledged the trio of approaching boats.