Sam entered the mouth of the cave.
He wore a pair of climbing overalls, harness, and helmet with light. He descended a wire caving ladder approximately twenty feet into the first passage. It was a narrow hallway, where a rocky slope ran in a gradual downward slope for approximately sixteen feet. Bats lined the ceiling above. Sam slowly made his way downward until he was forced to stop at a narrow collection of rocks that obstructed his passage, known in spelunking as a choke. He scrambled over the aptly termed choke by placing most of his weight on his hands and chest as he slid over the lip of the boulder, through the confined space that squeezed him with the stone above. He pulled himself through to the other side, where a fixed ladder descended another twenty feet onto a small ledge.
Sam studied the narrow crevasse into complete darkness below. It was small enough that he wondered how Tom would squeeze through. Their guide had spoken about the choke during their pre-caving and diving briefing. Malcom had identified the spot on the map and assured Tom that he would fit, but it would be a narrow squeeze. Now that Sam stared at the place, he wasn’t quite as confident. The only positive fact was that they would descend feet first, so if it became narrow for Tom, he could always climb out again.
He attached his figure eight descender to a fixed rope and descended vertically thirty-eight feet onto another ledge with a large pocket in the back, affectionately called The Closet by the guides who used it as a final gear staging area. The narrow passage and pocket were already crammed with climbing gear.
A guide from one of the other dive teams prepared an additional set of climbing equipment up on the ledge. The guide glanced at Sam as he descended. “How are you travelling, Mr. Reilly?”
“Good. Much further?”
The guide pointed along the edge. “Not much. You’re about half-way there. Malcom is down on the raft, getting your dive equipment set up.”
Sam nodded. “Thanks. See you down there.”
He disconnected from the first rope and attached himself to a new rope. With his descender firmly in place, he made the forty-eight foot abseil down a steep slope onto a bridge between two walls. Without changing ropes, Sam kicked off the final ledge, and abseiled into the free space one hundred and twenty-five feet onto the inflatable rafts on the water.
Four massive floodlights lit up the cavern that protected the nearly two hectares of subterranean lake, while a single submarine light glowed from fifty feet below the water’s surface. Sam glanced around the ancient world. Stalactites lined the roof like some sort of a fairy grotto, while stalagmites and fallen stalactites littered the beach to the east. The shallow water near the beach was a bright cobalt blue, while the deeper water toward the west of the lake was a rich ultramarine.
Chapter Twenty-Five
Sam watched as Tom abseiled down the final drop of the hole in the ceiling. He had apparently made it through the choke. The inflatable raft shook under his 260 pounds of muscle. He smiled through a state of hardened concentration as he landed. It was good to see him more like his usual self. They still had no idea where Billie had been taken prisoner, but at least now they were able to focus on something that might lead to her.
Sam said, “You made it.”
“Of course I made it.” Tom’s face softened into a smile. “Did you really think I’d get stuck in the narrow slot?”
“I did have some doubts,” Sam admitted.
Sam and Tom quickly changed into their dry suits. Lying on the raft next to them in a series of makeshift holding containers, were twelve steel dive tanks. Most were filled with Trimix, a unique combination of oxygen, helium and nitrogen designed to allow a diver to reach extraordinary depths. Two were white with black on top — 100 percent oxygen — if something went wrong and either of them suffered from any sort of Acute Decompression Sickness they would be too far from any hyperbaric chamber. Instead they would have to take the 100 percent oxygen and then perform in-water recompression in the lake.
The problem with SCUBA diving at great depths was that the additional pressure the further down you went turned otherwise harmless gasses lethal. Below a hundred feet, the increased partial pressure of nitrogen in the blood leads to a syndrome called nitrogen narcosis, where the person experiences symptoms similar to drunkenness and eventually loss of consciousness. Below two hundred feet, oxygen toxicity occurs, leading to seizures and death. The solution was Trimix, a unique combination of oxygen, helium and nitrogen. The current world record was held by a diver who reached a depth below 1000 feet using Trimix.
Malcom glanced at the number of tanks. Sam and Tom would each wear two on their back and one in front of them. The remaining tanks would be positioned at prearranged decompression stops. Even so, the risk was enormous. “You still want to dive to the bottom?”
Sam attached his first regulator. “We don’t have a choice. If there are drawings of a hidden pyramid down there, we need to see them.”
“You realize it might just be a hoax?”
Sam nodded. “Even so, we need to find out for ourselves.”
“It’s a long way down.” Malcom leaned over the edge of the raft to look into the ultramarine blue of the unmapped lake that emphasized its extreme depth. “Apart from the person who left that photograph at the Tsumeb road house, no one’s ever reached the bottom of this lake. They did do a deep dive here last week, but there’s no way to prove whether or not they reached the bottom, or even if its 410 feet.”
Tom slipped into his buoyancy control device. “We’ll let you know when we reach it.”
Malcom grinned at his temerity. “There’s something you haven’t thought about if you think that photo of hand drawings of a pyramid in the desert is at the bottom of this lake.”
“What’s that?” Sam asked.
Malcom smiled sympathetically, as though what he was about to reveal would crush their dreams. “How did they get there?”
Sam paused. “That’s a good question. The drawings, if they were true, depicted a ship from 1655. How often does this lake change its depth?”
“Since its discovery,” Malcom said, “the water level hasn’t changed a foot.”
Chapter Twenty-Six
Sam lowered the additional dive tanks to the staged decompression stops. He and Tom completed a final check on each other’s SCUBA equipment and stepped into the lake. He sank to roughly five feet and checked his dive computer and equipment. Everything was working fine.
“How are you looking, Tom?”
“Good. Let’s go find that picture.”
Sam swallowed to allow his ears to equalize as he descended. He and Tom dropped quickly, maintaining visual contact with each other throughout the process. The light from above served them adequately until they reached sixty feet. Sam switched on his dive flashlight and pointed it below. A large golden cave catfish glanced at them from blind eyes and swam past.
“I wonder if it tastes any good?” Tom asked.
“Don’t even think about it. That fish is unique to this cave only, and its numbers are estimated at less than a hundred and fifty.”
“Sure. But do you think it tastes any good?”
Sam ignored him. Instead he concentrated on his depth gauge. With no rain or other runoff affecting the lake, the visibility was unbelievably good, making it difficult to judge their descent. The lake started shallow at the beach on the eastern end of the cavern and headed deeper to the west. The tunnel narrowed the further west it went; the subsequent result being that while the lake’s surface measured at nearly two hectares, the bottom was no more than fifty feet at its widest point. It took Sam and Tom just under ten minutes to reach the cave’s bottom.