"Our research ship contained the necessary diving equipment," Pitt explained unemotionally. "I'm not a scientist but a marine engineer. I've only had a few training sessions in underwater recovery, but I'm a reasonably good diver."

    Before a discouraged Miller could reply, the helicopter's engine died as the rotor blades slowly swung to a stop, and a short man with the broad shoulders and barrel chest of a dock worker squeezed through the exit door and approached. He looked the complete opposite of the tall lean Pitt.

    My friend and associate, Al Giordino," Pitt said, introducing him.

    Giordino nodded under a mass of dark, curly hair and said simply, "Hello."

    Miller looked behind them through the windshield of the aircraft, and seeing the interior held no other passengers, groaned in despair. "Two of you, only two of you. My God, it will take at least a dozen men to bring them out."

    Pitt wasn't the least bit annoyed by Miller's outburst. He stared at the anthropologist with tolerant understanding through deep green opaline eyes that seemed to possess a mesmeric quality. "Trust me, Doc," he said in a tone that stopped any further argument. "Al and I can do the job."

    Within minutes, after a brief planning session, Pitt was ready to be lowered into the pool. He was wearing a full EXO-26 face mask from Diving Systems International with an exothermic air regulator good for polluted water applications. The earphone sockets were connected to an MK1-DCI Ocean Technology Systems diver radio. He earned twin 100-cubic-foot air tanks on his back and wore a buoyancy compensator with an array of instruments indicating depth, air pressure, and compass direction. As he geared up, Giordino connected a thick nylon Kermantle communications and safety line to Pitt's earphone and an emergency release buckle on a strap cinched around Pitt's waist. The remainder of the safety line wound around a large reel mounted inside the helicopter and connected to an outside amplifier. After a final check of Pitt's equipment, Giordino patted him on the head and spoke into the communication system's microphone.

    "Looking good. Do you read?"

    "As though you were inside my head," Pitt answered, his voice audible to everyone through an amplifier. "How about me?"

    Giordino nodded. "Clear and distinct. I'll monitor your decompression schedule and dive time from here."

    "Understood."

    "I'm counting on you to give me a running account of your situation and depth."

    Pitt wrapped the safety line around one arm and gripped it with both hands. He gave Giordino a wink from behind the lens of the face mask. "Okay, let's open the show."

    Giordino motioned to four of Miller's students who began unwinding the reel. Unlike Shannon and Miles who bounced their way down along the sinkhole walls, Giordino had strung the nylon line over the end of a dead tree trunk that hung 2 meters (over 6 feet) beyond the edge of the vertical precipice, allowing Pitt to drop without scraping against the limestone.

    For a man who was conceivably sending his friend to an untimely death, Miller thought, Giordino appeared incredibly calm and efficient. He did not know Pitt and Giordino, had never heard of the legendary pair. He could not know they were extraordinary men with almost twenty years of adventuring under the seas who had developed an unerring sense for assessing the odds of survival. He could only stand by in frustration at what he was certain was an exercise in futility. He leaned over the brink and watched intently as Pitt neared the green surface scum of the water.

    "How's it look?" asked Giordino over the phone.

    "Like my grandmother's split pea soup," replied Pitt.

    "I don't advise sampling it."

    "The thought never entered my mind."

    No further words were spoken as Pitt's feet entered the liquid slime. When it closed over his head, Giordino slackened the safety line to give him freedom of movement. The water temperature was only about ten degrees cooler than the average hot tub. Pitt began breathing through his regulator, rolled over, kicked his fins, and dove down into the murky world of death. The increasing water pressure squeezed his ear drums and he snorted inside his mask to equalize the force. He switched on a Birns Oceanographics Snooper light, but the hand-held beam could barely penetrate the gloom.

    Then, abruptly, he passed through the dense murk into a yawning chasm of crystal clear water. Instead of the light beam reflecting off the algae into his face, it suddenly shot into the distance. The instant transformation below the layer of slime stunned him for a moment. He felt as if he were swimming in air. "I have clear visibility at a depth of four meters," he reported topside.

    "Any sign of the other divers?"

    Pitt slowly swam in a 360-degree circle. "No, nothing."

    "Can you make out details of the bottom?"

    "Fairly well," replied Pitt. "The water is transparent as glass but quite dark. The scum on the surface cuts the sunlight on the bottom by seventy percent. It's a bit dark around the walls so I'll have to swim a search pattern so I won't miss the bodies."

"Do you have enough slack on the safety line?"

    "Maintain a slight tension so it won't hinder my movement as I go deeper."

    For the next twelve minutes Pitt circled the steep walls of the sinkhole, probing every cavity, descending as if revolving around a giant corkscrew. The limestone, laid down hundreds of millions of years earlier, was mineral stained with strange, abstract images. He planed horizontally and swam in languid slow motion, sweeping the beam of light back and forth in front of him. The illusion of soaring over a bottomless pit was overwhelming.

    Finally, he leveled out over the floor of the sacrificial pool. No firm sand or plant life, just one uneven patch of ugly brown silt broken by clusters of grayish rock. "I have the bottom at slightly over thirty-six meters. Still no sign of Kelsey or Rodgers."

    Far above the pool, Miller gave Giordino a dazed look. "They must be down there. Impossible for them to simply vanish."

    Far below, Pitt kicked slowly across the bottom, careful to stay a good meter above the rocks and especially the silt, which might billow into a blinding cloud and reduce his visibility to zero within seconds. Once disturbed, silt could remain suspended for several hours before settling back to the bottom. He gave an involuntary shudder. The water had turned uncomfortably cold as he passed into a cool layer suspended beneath the warmer water above. He slowed and drifted, adding enough lift from his compensator for slight buoyancy, achieving a slight head-down, fins-up swimming position.

    Cautiously, he reached down and gently sank his hands into the brown muck. They touched bedrock before the silt rose to his wrists. Pitt thought it strange the silt was so shallow. After countless centuries of erosion from the walls and runoff from the ground above, the rocky subsurface should have been covered with a layer at least 2 meters (over 6 feet) deep. He went motionless and floated over what looked like a field of bleached white tree limbs sprouting from the mud. Gripping one that was gnarled with small protrusions, he eased it out of the bed of silt. He found himself staring at a spinal column from an ancient sacrificial victim.

    Giordino's voice broke through his earphones. "Speak to me."

    "Depth thirty-seven meters," Pitt answered as he flung aside the spinal column. "The floor of the pool is a bone yard. There must be two hundred skeletons scattered around down here."