Hand over hand the lines were paid out as the divers began their descent into the ominous pool below. Shannon and Rodgers extended their legs and used the tips of their dive fins as bumpers to keep from scraping against the rough limestone walls. They could clearly see the coating of slime covering the surface of the water. It looked as viscous and about as inviting as a tub of green mucus. The aroma of decay and stagnation was overwhelming. To Shannon the thrill of the unknown abruptly changed to a feeling of deep apprehension.

    When they were within 1 meter (about 3 feet) of the surface, they both inserted their air regulator mouthpieces between their teeth and signaled to the anxious faces staring from above. Then Shannon and Miles slipped out of their harnesses and dropped out of sight into the odious slime.

    Miller nervously paced the rim of the sinkhole, glancing at his watch every other minute while the students peered in fascination at the green slime below. Fifteen minutes passed with no sign of the divers. Suddenly, the exhaust bubbles from their air regulators disappeared. Frantically Miller ran along the edge of the well. Had they found a cave and entered it? He waited ten minutes, then ran over to a nearby tent and rushed inside. Almost feverishly he picked up a portable radio and began hailing the project's headquarters and supply unit in the small town of Chachapoyas, 90 kilometers (56 miles) to the south. The voice of Juan Chaco, inspector general of Peruvian archaeology and director of the Museo de la Nacion in Lima, answered almost immediately.

    "Juan here. That you, Doc? What can I do for you?"

    "Dr. Kelsey and Miles Rodgers insisted on making a preliminary dive into the sacrificial well," replied Miller. "I think we may have an emergency."

    "They went into that cesspool without waiting for the dive team from the university?" Chaco asked in a strangely indifferent tone.

    "I tried to talk them out of it."

    "When did they enter the water?"

    Miller checked his watch again. "Twenty-seven minutes ago."

    "How long did they plan to stay down?"

    "They planned to resurface after thirty minutes."

    "It's still early." Chaco sighed. "So what's the problem?"

    "We've seen no sign of their air bubbles for the last ten minutes."

    Chaco caught his breath, closed his eyes for a second. "Doesn't sound good, my friend. This is not what we planned."

    "Can you send the dive team ahead by helicopter?" asked Miller.

    "Not possible," Chaco replied helplessly. "They're still in transit from Miami. Their plane isn't scheduled to land in Lima for another four hours."

    "We can't afford government meddling. Certainly not now. Can you arrange to have a dive rescue team rushed to the sinkhole?"

    "The nearest naval facility is at Trujillo. I'll alert the base commander and go from there."

    "Good luck to you, Juan. I'll stand by the radio at this end."

    "Keep me informed of any new developments."

    "I will, I promise you," Miller said grimly.

    "My friend?"

    "Yes?"

    "They'll come through," offered Chaco in a hollow tone. "Rodgers is a master diver. He doesn't make mistakes."

    Miller said nothing. There was nothing more to say. He broke contact with Chaco and hurried back to the silent group of students, who were staring down into the sinkhole with dread.

    In Chachapoyas, Chaco pulled out a handkerchief and mopped his face. He was a man of order. Unforeseen obstacles or problems irritated him. If the two stupid Americans drowned themselves, there would be a government inquiry. Despite Chaco's influence, the Peruvian news media were bound to make an overblown incident out of it. The consequences might very well prove to be nothing less than disastrous.

    "All we need now," he muttered to himself, "are two dead archaeologists in the pool."

    Then with shaking hands he gripped the radio transmitter and began sending out an urgent call for help.

    One hour and forty-five minute had passed since Shannon and Miles had entered the sacrificial pool. Any attempt at rescue now seemed an empty gesture. Nothing could save Shannon and Miles now. They had to be dead, their air used up long ago. Two more victims added to the countless number who had disappeared into the morbid waters through the centuries.

    In a voice frantic with desperation, Chaco had informed him that the Peruvian navy was caught unprepared for an emergency. Their water escape and recovery team was on a training mission far to the south of Peru near the Chilean border. It was impossible for them to airlift the dive team and their equipment to the sinkhole before sundown. Chaco helplessly shared Miller's anxiety over the slow response time. But this was South America and speed was seldom a priority.

    One of the female students heard it first. She cupped her hands to her ears and turned back and forth like a radar antenna. "A helicopter!" she announced excitedly, pointing in a westerly direction through the tops of the trees.

    In an expectant hush everyone around the rim of the pool listened. The faint thumping sound of a rotor blade beating the air came toward them, growing louder with each passing moment. A minute later a turquoise helicopter with the letters NUMA painted on its sides swept into view.

    Where had it come from? Miller wondered, his spirits rising. It obviously didn't have the markings of the Peruvian navy. It had to be a civilian craft.

    The tops of the surrounding trees were whipped into a frenzy as the helicopter began its descent into a small clearing beside the sinkhole. The landing skids were still in the air when the fuselage door opened and a tall man with wavy black hair made an agile leap to the ground. He was dressed in a thin, shorty wet suit for diving in warm waters. Ignoring the younger people, he walked directly up to the anthropologist.

    "Dr. Miller?"

    "Yes, I'm Miller."

    The stranger, a warm smile arched across his face, shoved out a calloused hand. "I'm sorry we couldn't have arrived sooner."

    "Who are you?"

    "My name is Dirk Pitt."

    "You're American," Miller stated, staring into a craggy face with eyes that seemed to smile.

    "Special Projects Director for the U.S. National Underwater and Marine Agency. As I understand it, two of your divers are missing in an underwater cave."

    "A sinkhole," Miller corrected him. "Dr. Shannon Kelsey and Miles Rodgers entered the water almost two hours ago and have failed to resurface."

    Pitt walked over to the edge of the pool, stared down at the stagnant water, and quickly determined that diving conditions were rotten. The pool went from slime green at the outer edges to pitch black in the center, giving the impression of great depth. There was nothing to indicate that the operation would prove to be anything more than a body recovery. "Not too inviting," he mused.

    "Where did you come from?" queried Miller.

    "NUMA is conducting an underwater geological survey off the coast due west of here. The Peruvian naval headquarters radioed a request to send divers on a rescue mission and we responded. Apparently we're the first to arrive on-site."

    "How can oceanographic scientists carry out a rescue and recovery operation in a hellhole?" Miller snapped, becoming suddenly angry.