“That’s underwater,” Summer said.
“It wouldn’t have been when the Aztecs were here.” Torres’s voice had a new optimism. “The lake was created by a dam built some twenty-five years ago.”
Dirk dragged his finger to the middle of the reservoir. “If you were drawing a picture of the cave from this vantage point, the peak of Lomo del Toro would rise above and just beyond the top of the bluff. The codex image would still fit.”
“Yes, yes,” Torres said, his face lighting up. “Are you up to the task of searching in the water?”
Dirk gave the professor a wink. “Could an Aztec priest carve a turkey?”
15
They plunged into the reservoir from a shoreline ledge, finding the water cool and the visibility clear. Summer involuntarily shivered in the water that was not as warm as the cenote where they had last dived. She hovered a moment at the ten-foot mark to clear her ears, then swam after her brother, who was already descending rapidly. After Torres had found a path to the water’s edge, the siblings had assembled their dive gear in record time, leaving the archeologist to pace the shoreline.
Dirk followed the gradient until it leveled at sixty feet. The lake bed was a bland tableau of rocks and brown mud that resembled a moonscape. Any sign of a riverbed was long since hidden, covered by sediment built up since the dam was constructed. Dirk knew the original watercourse had followed the base of the ridge, and when Summer joined his side, he took off across its steep face.
They could look up the face of the ridge nearly to the surface. They swam in short spurts, methodically surveying the rock wall in hope of spotting a cave-like opening. Numerous times they were deceived by shadows and narrow fissures that led nowhere. Both were strong swimmers, and with little current in the lake, they quickly advanced several hundred yards along the base of the ridge.
The feature gradually sharpened to a near-vertical rise. Dirk was looking ahead to the next contour when he felt Summer grip his arm. She pointed to the rock incline at his side. A small indentation was visible where his fin had knocked away some silt. He stuck his fingers into the crevice and scooped away a thick handful of mud. The water turned murky, but a minute later it cleared and they could see the indentation was a carved step. Summer ran her hand above the cut and found another hollow. Scooping away the mud inside, she exposed it as another step, carved directly above the first one.
She pointed up the face of the rock and began ascending. Every foot or so, she found another step filled with sediment. About forty feet above her, Summer noticed a dark spot and her heart skipped a beat.
It appeared little different than the rock shadows that had deceived them earlier, but she became more intrigued when a pair of fish emerged from the darkness. Dirk followed Summer as she ascended, following the buried flight of steps. Drawing close to the rock shadow, she saw a thick ledge protruding from the wall above her, obscuring the view farther up.
With a strong kick of her fins, she broached the rim and peered over the top. Just beyond was an oval recess in the rock wall. Neatly concealed by the ledge, and accessible only by the steps when the land was dry, the cave would have been a highly defensible hideaway for its ancient occupants.
Summer waited until her brother joined her on the ledge. She then flicked on a dive light and swam through the slim opening, startling a large bass that darted out of the darkness. Dirk followed her, careful not to scrape the floor with his fins and kick up a cloud of sediment.
The small opening led a short distance before expanding into a house-sized cavern. Removed from the surface light, the interior was black and ominous, save for the thin illumination of their dive lights. The ceiling soared high above them, allowing the divers to float easily while surveying the interior. But there was little to observe. A rock fire pit occupied the center of the cave floor, while an orderly mound of crushed rock was piled against the back wall. There was no sign of the half stone, or any other artifacts.
Dirk swam to a side wall and examined it with his light. Crude scars peppered the surface, indicating the rocks in the pile had been hammered from the wall. He picked up one of the rocks and held it to his dive mask. It was a heavy chunk of granite flecked with silver. Someone had discovered a vein of the ore and made a primitive attempt to mine it. Could it have been the Aztecs?
He pocketed the rock and joined Summer, who was slowly swimming circular laps with her light pointed at the floor. The excitement in her eyes had vanished and she gave her brother a disappointed shake of her head. Dirk pointed toward the entrance and motioned to leave.
Summer followed, keeping her light pointed at the floor. As they crossed the center of the cave, her light caught the fire pit. She had examined it earlier but found only a ring of rocks over a mud floor. Now she noticed there were no charred sticks or signs of charcoal. Nor were the rocks blackened. She hesitated and then noticed the rocks’ alignment. They didn’t actually form a round pit but were instead positioned in a semicircle.
She reached out and snared Dirk’s ankle before he swam out the entrance, then dropped down to the fire pit. He turned his light on her as she glided above the pit and plunged a hand into its center. Summer’s fingers drove through several inches of sediment before reaching a hard surface. Sliding her hand against it, she could tell it was flat.
Her pulse quickened as she scooped the mud from the fire pit in thick handfuls. Fine particles rose through the water, deflecting their lights and turning the visibility to soup. Dirk released a shot of air from his buoyancy compensator and descended to the floor, feeling Summer’s elbow as she continued to sling mud. He felt her movements stop and they both lay quietly, waiting for the water to clear.
It felt like an eternity to Summer, but it was only a minute or two before the water began to become clear. She saw Dirk’s light appear, then the shape of his wetsuit. Together, they turned their lights toward the fire pit, where Summer’s hand still rested. As her fingers came into view, she traced the outline of a large, flat object. Brushing away a thin layer of sand, she pressed her face down to see.
The carved head of a bird gazed back at her, surrounded by an assortment of stylized glyphs like those in the codex. Summer winked at her brother and pointed at the figures.
She had found the Aztec stone.
16
The stone was too unwieldy to carry any distance, so Summer and Dirk left it in place and swam out of the cave. Dirk had carried a small lift bag attached to his buoyancy compensator. He inflated it with his regulator and tied it to a rock near the entrance. The small bag floated to the surface, providing a marker for the cave. Dirk and Summer followed it up, then swam along the ridge wall to where Torres waited impatiently.
The archeologist leaped like a drunken leprechaun when Summer described their find. “It was carved in a semicircle?”
“Yes,” Summer said, “exactly as if it had been cut in half. It was full of carved glyphs, just like the ones in the codex.”
“Fantástico! Can you remove it from the cave?”
“Yes, but we’ll never get it here.” She pointed to a tiny orange speck in the water. Dirk’s float bag lay almost a quarter mile away.
“We’ll have to move the van closer,” Dirk said. He eyeballed the top of the ridge, then borrowed Torres’s topographic map. “If we circle around the back of the ridge, I think we can drive over the top and descend directly above the cave. There’s a tapered gully nearby where we could access the lake.”
Summer nodded. “We could hoist it straight up the face of the bluff. There’s a coil of rope in the back of the van we can use.”