As she flew through the water, Danielle heard Hawker’s voice over the radio, doing a bad job of impersonating Jacques Cousteau. “And zey dove into zee murky depths, in search of zee giant octopus. Although it was not so murky as zey expected and zey weren’t really diving zat deep.”

She smiled to herself. Seawater absorbs and scatters light fairly rapidly but as they passed through forty feet it was bright and clear and pristine blue. With the light-colored, sandy bottom, it would only be slightly darker at eighty feet.

From the corner of her eye she saw Hawker pull up and turn.

She backed off the throttle and the two of them hung there, floating in zero g.

“What’s wrong?” she asked.

He pointed into the distance.

“Sharks.”

CHAPTER 30

Danielle watched as a large shape materialized in the distance,

“Hammerhead,” she whispered.

“As long as it’s not the one that jumps out of the water with people in its mouth,” Hawker said.

In the time she’d known Hawker, she’d found he liked to make light of situations, using humor to prop up people’s spirits or to defuse a situation. She didn’t detect that he was actually worried, but a twenty-foot, thousand-pound shark was not something to take lightly.

“Hammerheads usually ignore people,” she said, looking around in the other directions. “But the problem is …”

Even as she spoke two more of the oddly shaped fish came gliding in from out of the darkness, and then a third, fourth, and fifth.

“The problem is they tend to swim in packs,” she said.

The sharks were cruising near the surface, moving methodically, almost lazily out toward the limit of her vision. She nudged the throttle and began to ease forward.

“What are you doing?” Hawker asked.

“I just want to see where they’re going,” she said.

“How about we just let them go there,” he suggested.

That would have been fine by her. But the problem was she didn’t think they were going anywhere. She had a sneaking suspicion that they might be moving out beyond visual range and turning back toward the two human swimmers.

She continued the slow pursuit until she could see them more clearly. The sharks had changed course, but not back toward her and Hawker; they’d banked left, turning due south. She wanted to follow farther, but even though the sharks were swimming at a leisurely pace, there was no way to keep up with them short of gunning the throttles on the DPVs, and that didn’t seem wise, since she knew that sharks are acutely aware of vibrations.

“Danielle,” Hawker said, “you might want to turn around.”

She released the throttle and turned in Hawker’s direction. More sharks were headed their way. Not one or two or five, this time, but twenty or thirty or fifty, strung out in a long line two and three wide, like rush hour drivers on some underwater highway.

Like her, Hawker was sinking noiselessly toward the bottom. It seemed like a prudent idea. They touched down in the sand. From there Danielle had a better view. Looking upward, with the sharks backlit by the sunlight, she followed their progress. She could see what they were doing now, swimming in a half-mile-wide circle. Slowly meandering along, turning and swimming and turning and swimming, the way fish in circular aquariums do.

“Not that I wouldn’t rather be watching this from a submarine,” Hawker said, “but this is pretty cool.”

“I’ve heard they can gather in groups of hundreds,” she said, “but I’ve never seen anything like this.”

“How many do you think there are?”

It was impossible to count, but as she watched them circle, she guessed there were more than a hundred of them, maybe close to two hundred. The larger ones swam out on their own, in the outside lane so to speak. The smaller ones, seven- and eight-footers, stuck closer together in tight groupings on the inside of the circular track.

As she tried to take in the whole scene, she gazed across the seafloor toward what would have been the center of the shark circle. There a ridge of coral and what looked like an outcropping of stone rose from the silt.

And suddenly it made sense to her. Sharks, hammerheads in particular, had sensitive organs in their snouts that detected electromagnetic pulses. The small organs were called the ampullae of Lorenzini, and were basically bundles of nerve fibers that reacted to changes in electromagnetic waves.

If they were right about the possibility of another stone being present in this area, then perhaps the sharks sensed that energy and it was drawing them in, similar to what had happened with Yuri on the boat moments before.

Only, for the sharks, there were no restrictions to hold them back and their desire to be here resulted in this endless circling pattern. The same way moths flicker in circles around candlelight, thinking it’s the moon. They can never quite reach it, but they can’t leave it, either.

As she stared at the sharks, slowly turning above them, she found the scene almost hypnotic. Slightly dizzy, she looked away, toward the coral-covered outcropping across from them.

A few deep breaths cleared her head and she spoke.

“I think we should go over to that coral rise. It’s in the right place. If one of the stones is down here, then I’m guessing that’s where we’ll find it.”

Moving slowly and keeping an eye on the sharks above, they swam up to the outcropping of rock. Peeking out from beneath a coral blanket were great stones cut and laid in precise diagonal blocks, interlocking and supporting one another.

Danielle swam around the side, finding an exposed corner and the line of an edge.

“It looks pretty much intact,” she said.

Hawker was examining the fit of the stones. “If the exterior is secure, the interior might be as well.”

“Just like McCarter said: hard to find, but impossible to lose,” she said.

“And well defended,” he noted, nodding to the sharks. “Just like the temple in Brazil.”

Danielle examined the edges of the structure. She could see designs in the stonework. They weren’t hieroglyphic but they were similar to other Mayan designs McCarter had shown her. Warrior figures and the outline of the Witz Monster, a Mayan representation connected to the rain god. In this case the mouth had a pair of serpents suspended within it.

The discovery sent a wave of adrenaline through her body. In fact she felt positively rapturous. “Let’s see if there is a way to get inside.”

They glided across the top of the structure, with one eye on the sharks, then they dropped down on the other side.

Danielle arrived at the bottom, beside a hollow-looking area in the web of coral. She aimed her flashlight inside.

“A tunnel.”

It was narrow and cramped with jagged outcroppings of coral growing along the walls, but she felt it was worth a try.

Hawker grabbed her arm. “You’ll fit but your tanks won’t.”

In her excitement she’d almost forgotten. The double tanks on her back were bulky and their cross section was actually wider than her hips. She slipped them off.

“Don’t,” Hawker said.

“I’m just taking a look.”

She disconnected her regulator, dropped her tanks, and kicked her way forward. After easing into the tunnel for fifteen feet or so it began to narrow around her. She moved back outside and connected to the regulator for a moment.

Hawker was staring at her as if she were crazy.

“Relax,” she said, confidently. “I’m skinny and you’re worrying for nothing.”

She took a series of deep breaths, trying to hyperoxygenate her body as free divers do. With a little luck she’d have three or four minutes of air. It was a risk, but she felt certain that what they were looking for was right around the corner. McCarter’s translation and calculations, Yuri’s reaction, the sharks—it all made sense. The second stone was inside. It had to be there. And she had the power to go get it.