"Still no sign of bodies?"

    "Not yet."

    Pitt began to feel an icy finger trail up the nape of his neck as he spotted a skeleton with a bony hand pointing into the gloom. Beside the rib cage was a rusty breastplate, while the skull was still encased in what he guessed was a sixteenth-century Spanish helmet.

    Pitt reported the sighting to Giordino. "Tell Doc Miller I've found a long-dead Spaniard complete with helmet and breastplate down here." Then, as if drawn by an unseen force, his eyes followed in the direction a curled finger of the hand pointed.

    There was another body, one that had died more recently. It appeared to be a male with the legs drawn up and the head tilted back. Decomposition had not had time to fully break down the flesh. The corpse was still in a state of saponification, where the meaty tissue and organs had turned into a firm soaplike substance.

    The expensive hiking boots, a red silk scarf knotted around the neck, and a Navajo silver belt buckle inlaid with turquoise stones made it easy for Pitt to recognize someone who was not a local peasant. Whoever he was, he was not young. Strands of long silver hair and beard swayed with the current from Pitt's movements. A wide gash in the neck also showed how he had died.

    A thick gold ring with a large yellow stone flashed under the beam of the dive light. The thought occurred to Pitt that the ring might come in handy for identifying the body. Fighting the bile rising in his throat, he easily pulled the ring over the knuckle of the dead man's rotting finger while half expecting a shadowy form to appear and accuse him of acting like a ghoul. Disagreeable as the job was, he swished the ring through the silt to clean off any remnant of its former owner, and then slipped it onto one of his own fingers so he wouldn't lose it.

    "I have another one," he notified Giordino.

    "One of the divers or an old Spaniard?"

    "Neither. This one looks to be a few months to a year old."

    Do you want to retrieve it?" asked Giordino.

    "Not yet. We'll wait until after we find Doc Miller's people-" Pitt suddenly broke off as he was struck by an enormous force of water that surged into the pool from an unseen passage on the opposite wall and churned up the silt like dust whirling around a tornado. He would have tumbled out of control like a leaf in the wind by the unexpected energy of the turbulence but for his safety line. As it was he barely kept a firm grip on his dive light.

    "That was a hell of a jerk," said Giordino with concern. "What's going on?"

    "I've been struck by a powerful surge from nowhere," Pitt replied, relaxing and allowing himself to go with the flow. "That explains why the silt layer is so shallow. It's periodically swept away by the turbulence."

    "Probably fed by an underground water system that builds up pressure and releases it as a surge across the floor of the sinkhole," Giordino speculated. "Shall we pull you out?"

    "No, leave me be. Visibility is nil, but I don't seem to be in any immediate danger. Slowly release the safety line and let's see where the current carries me. There must be an outlet somewhere."

    "Too dangerous. You might get hung up and trapped."

    "Not if I keep from entangling my safety line," Pitt said easily.

    On the surface, Giordino studied his watch. "You've been down sixteen minutes. How's your air?"

    Pitt held his pressure gauge in front of his face mask. He could barely read the needle through the maelstrom of silt. "Good for another twenty minutes."

    "I'll give you ten. After that, at your present depth, you'll be looking at decompression stops."

    "You're the boss," Pitt came back agreeably.

    "What's your situation?"

    "Feels like I'm being pulled into a narrow tunnel feet first. I can touch the walls closing around me. Lucky I have a safety line. Impossible to swim against the surge."

    Giordino turned to Miller. "Sounds as if he may have a lead on what happened to your divers."

    Miller shook his head in anger. "I warned them. They could have avoided this tragedy by keeping their dive in shallow depths."

    Pitt felt as though he was being sucked through the narrow slot for an hour when it was only twenty seconds. The silt cloud had faded slightly, most of it remaining in the deep pool behind. He began to see his surroundings more clearly. His compass showed he was being carried in a southeasterly direction. Then the walls suddenly opened out into one enormous, flooded room. To his right and below he caught the momentary flash of something glinting in the murk. Something metallic vaguely reflecting the silt-dimmed beam of his dive light. It was an abandoned air tank. Nearby was a second one. He swam over and peered at their pressure gauges. The needles were pegged on empty. He angled his dive light around in a circle, expecting to see dead bodies floating in the darkness like phantom demons.

    The cool bottom water had drained away a measure of Pitt's strength and he could feel his motions becoming sluggish. Although Giordino's voice still came through the earphones as clearly as if Pitt was standing next to him, the words seemed less distinct. Pitt switched his mind off automatic and put it on full control, sending out instructions to check data gauges, safety line, and buoyancy compensator as if there were another Pitt inside his head.

    He mentally sharpened his senses and forced himself to be alert. If the bodies were swept into a side passage, he thought, he could easily pass them by and never notice. But a quick search turned up nothing but a pair of discarded swim fins. Pitt aimed the dive light upward and saw the reflective glitter of surface water that indicated the upper dome of the chamber contained an air pocket.

    He also glimpsed a pair of white feet.

    Trapped far from the outside world in a prison of perpetual silence, breathing in a small pocket of air millions of years old and lying smothered in total blackness deep under the earth is too alien, too terrible to imagine. The horror of dying under such terrifying conditions can provide nightmares on a par with being locked in a closet full of snakes.

    After initial panic had passed and a small degree of rationality was retrieved, any hope that Shannon and Rodgers had of surviving vanished when the air in their tanks became exhausted and the final spark of life in the batteries of their dive lights gave out. The air in the small pocket soon became foul and stale from their own breathing. Dazed and lightheaded from lack of oxygen, they knew their suffering would only end when the watery chamber became their tomb.

    The underground current had sucked them into the cavern after Shannon had excitedly dived to the bottom of the sinkhole after glimpsing the field of bones. Rodgers had faithfully followed and exhausted himself in a frantic effort to escape the surge. The last of their air had been used up in a vain attempt to find another passage leading out of the chamber. There was no exit, no escape. They could only drift in the blackness, held afloat by their buoyancy compensators, and wait to die.

    Rodgers, for all his guts, was in a bad way, and Shannon was just hanging on by a thread when suddenly she noticed a flickering light in the forbidding water below. Then it became a bright, yellow beam stabbing the blackness in her direction. Was her numbed mind playing tricks? Did she dare entertain a glimmer of hope?

    "They've found us," she finally gasped as the light moved toward her.