He fired up the engine mounted on a large portable generator, then pulled a lever on a junction box. The mine shaft was suddenly illuminated under a series of exposed light bulbs that trailed down the shaft for a hundred yards before gradually growing smaller, until they became tiny glimmers in the distance. An ore cart sat on the rail tracks, attached to a cable that led to a winch. The cart was built to last, and the only sign of hard use was the rust on the sides of the bucket.

Marquez climbed into the bucket and pressed a button on a remote control. The winch began to hum and play out the cable, allowing the ore cart to roll down the rails, propelled by nothing more than gravity. Going underground was not for the fainthearted or the claustrophobic. The confining shaft barely allowed clearance for the ore bucket. Timbers bolted together like doorframes, known as a cap and post, were spaced every few feet to shore up the roof against cave-ins. Many of the timbers had rotted badly, but others were as solid and sound as the day they were set in place by miners who had long since passed on. The ore car descended the sloping shaft at a rapid rate, coming to a stop 1,200 feet into the depths. At this level there was a constant trickle of water falling from the roof of the tunnel.

Taking a backpack and his lunch pail, Marquez climbed from the car and walked over to a vertical shaft that fell away into the lower reaches of the old Paradise Mine until it reached the 2,200-foot level. Down there, the main drift and crosscut tunnels spread into the granite like spokes on a wheel. According to old records and underground maps, there were almost a hundred miles of tunnels under and around Pandora.

Marquez dropped a rock into the yawning blackness. The sound of a splash came within two seconds.

Soon after the mine closed down and the pumps at the pumping station below the base of the mountain were turned off, the lower levels had flooded. Over time, water had risen to within fifteen feet of the 1,200-foot level, where Marquez worked the rhodochrosite vein. The slowly rising water, spurred on during a particularly heavy wet season in the San Juans, told him that it would be only a matter of a few weeks before it reached the top of the old shaft and spilled over into the main tunnel, spelling the end of his gemstone-mining operation.

Marquez set his mind on extracting as many stones as he could in the brief time he had left. His days became longer as he struggled to remove the red crystals with nothing but his miner's pick and a wheelbarrow to carry the ore to the bucket for the ride up to the mine's entrance.

As he walked through the tunnel, he stepped around old rusting ore cars and drills left by the miners when they had deserted the mine. There had been no market for the equipment, since nearby mines were closing down one by one at the same time. It was all simply cast aside and left where it was last used.

Seventy-five yards into the tunnel, he came to a narrow cleft in the rock just wide enough for him to slip through. Twenty feet beyond was the rhodochrosite lode he was mining. A light bulb had burned out on the string hanging from the roof of the cleft, and he replaced it with one of several he kept in a backpack. Then he took his pick in hand and began to attack the rock that was embedded with the gemstones. A dull red in their natural state, the crystals looked like dried cherries in a muffin.

A dangerous overhang of rock protruded just above the cleft. If he was to continue to work safely without being crushed by a rockfall, Marquez had no choice but to blast it away. Using a portable pneumatic drill, he bored a hole into the rock. Then he inserted a small charge of dynamite and wired it to a handheld detonator. After moving around the corner of the cleft and into the main tunnel, he pushed down on the plunger. A dull thump echoed through the mine, followed by the sound of tumbling rock and a blanket of dust that rolled into the main tunnel.

Marquez waited a few minutes for the dust to settle before carefully entering the natural cleft. The overhang was gone. It had become a pile of rocks on the narrow floor. He retrieved the wheelbarrow and began removing the debris, dumping it a short distance up the tunnel. When the cleft was finally cleared, he looked up to make certain that no threatening section of the overhang remained.

He stared in wonder at a hole that had suddenly appeared in the roof above the crystal lode. He aimed the light atop his hard hat upward. The beam continued through the hole into what appeared to be a chamber beyond. Suddenly consumed by curiosity, he ran back up the tunnel for fifty yards, where he found the rusty remains of a six-foot iron ladder among the abandoned mining equipment. Returning inside the cleft, he propped up the ladder, climbed the rungs, and pried loose several rocks from the rim of the hole, widening it until he could squeeze through. Then he thrust his upper torso inside the chamber and twisted his head from shoulder to shoulder, sweeping the beam of his hard hat's light around the darkness.

Marquez found himself staring into a room hewn in the rock. It looked to be a perfect cube approximately fifteen by fifteen feet, with the same distance separating the floor and roof. Strange markings were cut into the sheer, smooth walls. This definitely was not the work of nineteenth-century miners. Then, abruptly, the beam of his hard hat's light struck a stone pedestal and glinted on the object it supported.

Marquez froze in shock at the ungodly sight of a black skull, its empty eye sockets staring directly at him.

The pilot banked the United Airlines Beechcraft twin-engine plane around a pair of cotton-fluffed clouds and began his descent toward the short runway on a bluff above the San Miguel River. Though he had flown in and out of the little Telluride airport a hundred times, it was still a chore for him to keep his concentration on landing the aircraft and not on the incredible aerial view of the spectacular snowcapped San Juan Mountains. The serene beauty of the jagged peaks and slopes, mantled with snow under a vivid blue sky, was breathtaking.

As the plane dropped lower into the valley, the slopes of the mountains rose majestically on both sides. They appeared so close that it seemed to the passengers as if the aircraft's wings would brush the aspen trees on the rocky outcroppings. Then the landing gear dropped, and a minute later the wheels thumped and screeched as they touched the narrow asphalt runway.

The Beechcraft carried only nineteen passengers, and the unloading went quickly. Patricia O'Connell was the last one to step to the ground. Taking the advice of friends who had flown into the resort town for the skiing, she had asked for a rear seat so she could enjoy the fantastic view without its being blocked by one of the aircraft's wings.

At 9,000 feet in altitude, the air was thin but incredibly pure and refreshing. Pat inhaled deeply as she walked from the plane to inside the terminal building. As she passed through the door, a short, stocky man with a shaved head and a dark brown beard walked up to her.

"Dr. O'Connell?"

"Please call me Pat," she replied. "You must be Dr. Ambrose."

"Please call me Tom," he said, with a warm smile. "Did you have a good flight from Denver?"

"It was wonderful. A little rough coming over the mountains, but the beautiful scenery easily offset any discomfort."

"Telluride is a lovely spot," he said wistfully. "There are times I wish I could live here."

"I don't imagine there are many archaeological sites to study for a man of your experience."

"Not this high," he said. "The ancient Indian ruins are at much lower altitudes."