Subterrestrial (13 page)

Thyssen watched Duan slide down the rope. He was the last one. They were all assembled and on the cusp of making history.

“
Echo One, do you copy?
” a voice crackled through his in-ear transceiver. The communication system allowed him to remain in contact with the surface via the microphone affixed to his palm—for as long as they were able to maintain a connection, anyway. He turned away from the others and whispered into his hand.

“Copy, Speranza.”

“
I think we have a problem up here,
” Butler said.

“You think?”

“
We have a problem, Echo One. We’ve lost contact with Echo Four.
”

“He and his men are supposed to be on their way down here by now.”

“
Wiley’s been unable to reach them and the others are still on the mainland.
”

“Get them down here when they arrive. I want them shadowing our movements. We need a discreet armed escort that won’t frighten the civilians.”

“
What about Echo Four?
”

“Can’t you geolocate his beacon?”

“
That’s the thing. We can’t seem to get a read on that, either.
”

Calder mentally rehearsed their route, over and over. Already she’d lost track of time and had no idea whether it was day or night outside, or even what day it actually was. She’d spent considerable time on the ocean floor in darkness beyond the sun’s reach, but she’d always known where she was and exactly how to get back to the boat. Everything was different down here. Getting out wasn’t going to be as simple as swimming to the surface. In a pinch, would she even be able to climb back up the chute she just descended?

She forced herself to think about it logically. Regardless of its location, water behaved in a predictable fashion. It always flowed with gravity and there was always both a source and an outlet. All water eventually flowed to the sea. As long as there was a current, there was a means of escape. The only problem was she had no clue how long or far she might have to travel underground before she reached the open ocean. She’d dived in plenty of caves along the Yucatan Peninsula in flooded karst formations similar to these. That wasn’t the part that frightened her; it was the possibility that she might have to do so with a paltry fifteen minutes of air.

The others didn’t appear nearly as concerned, but they undoubtedly hadn’t watched someone drown. Nor had they seen what an aquatic predator could do when its habitat was threatened. With every foot of descent, she became more and more certain that it was only a matter of time before they did.

Why else would Halversen have brought her here? All of this talk of hominin evolution and special migration was outside of her area of expertise. The others? Their specialties all dovetailed nicely with one another’s. Hers, though? Hers was unique among them, unless one classified humans as predators. And gave them gills. The only reasonable use for her talents would be to help find whatever killed those sea lions, although she couldn’t fathom which species it could have been. The sheer quantity of blood all but confirmed they’d been attacked on land. The image of a shark swimming through these caverns was terrifying. One that could simultaneously overcome what looked like four sea lions, though? And on dry land?

She clenched her hands into fists to keep them from shaking and tried to think about anything else.

The ceiling of the cavern was low and flat and maybe twice her height. Water trickled down the columns connecting the floor to the roof and accumulated in pools that reflected all of their lights. Their footsteps were made hollow by the acoustics. She heard their intonation change and watched Mitchell’s light constrict onto a flowstone wall and the triangular orifice eroded through it. She wanted to pull him aside and talk to him in private. If anyone would understand her concerns, it was he. Not just because he knew the dangers of diving on the best of days, let alone under circumstances like these, but because he’d spent considerable time exploring down here and had possibly seen some evidence of the reason that she, specifically, was here. And she didn’t want to have that conversation in front of Thyssen. She couldn’t explain why, but she didn’t trust him.

The passageway was so narrow that Mitchell had to turn sideways and duck his head. Thyssen and the others followed suit, their lights dimming. Calder hesitated. A shiver rippled up her spine. It struck her just how vulnerable she was at that precise moment and she hurried to catch up with the rest of her party, the majority of whom had already passed through the tunnel and stood silhouetted on the other side.

Damn Thyssen. She was going to corner Mitchell anyway. Something wasn’t right. She could feel it in her bones. In order to understand predators in the wild, one had to first understand the habits and behavior of their prey, which was exactly how she was beginning to feel.

She nearly barreled into the others when she burst from the far end of the passage. They stood on a stone pinnacle, high above an amoeboid swatch of water surrounded by jutting stalagmites of varying height, some of which formed columns that supported a narrow limestone arch across the width of the cavern.

“There’s no way of knowing if it’ll support our weight,” Payton said.

“We cross one at a time,” Thyssen said.

“Are you volunteering?” Nabahe said.

“Fine. I’ll go first. Give me a rope so you can belay me back up if I fall.”

“If it breaks, there’s no other way across,” Duan said. “Our only option would be to go down.”

Calder peered down at the water. Her light reflected off ripples and eddies and beneath their voices, she heard the rumble of the current. Its depth betrayed just how fast it was moving.

“We could always backtrack,” Payton said. “Maybe we missed something.”

Calder took Mitchell by the elbow and guided him away from the others.

“I need to talk to you.” He opened his mouth to speak, but she cut him off. “Privately.”

Mitchell glanced toward where Thyssen fed a climbing rope through his harness. He inclined his head back toward the tunnel and led her out of earshot.

“What’s
really
going on here?” she whispered.

“I don’t know what you—”

“You know exactly what I mean.”

Mitchell started to object, then peered back at the others. Thyssen was already a dozen steps out onto the narrow limestone formation, which was barely wide enough for him to place his feet together. He held his arms out for balance as he scooted above the river.

“I don’t know. Not for sure, anyway.”

“But something’s not right.”

“Like I said, I don’t know anything for sure—”

“You can feel it, though. Like that subtle change you feel in the water when a shark swims into a reef.”

She could see in his eyes that he knew what she meant. Divers learned to trust their instincts, which were often their only allies in dangerous seas. He averted his stare.

“Yeah,” he whispered. The faint sound of droplets of condensation striking the pooled water echoed from the chamber behind them. “Something like that.”

Thyssen had reached the other side and released the rope from his harness. Duan reeled it back, hand over fist. He tied it to Hart’s harness and helped her out onto the natural bridge.

“What do you think killed those sea lions?”

Hart lowered herself to all fours and crawled across. Thyssen untied her and tossed the rope out over the nothingness for Duan to haul back in.

There was a splashing sound behind them. Calder resisted the urge to look. She wanted to watch Mitchell’s face to see if he was lying.

“Honestly? I don’t have a clue. I’ve seen orcas do that kind of damage, but I can’t see one surviving down here for any length of time. We get great whites this far north. Sleeper sharks, too. And we have seasonal goblin sharks, but they’re too small to take down a single sea lion, let alone that many.”

Payton walked confidently across the bridge without so much as looking down.

“What does your gut tell you?”

“We’re dealing with something terrestrial. Polar bears, most likely.”

Nabahe struck off across the arch, one cautious step at a time.

“All the way down here?”

A damp slapping sound, like the bare foot of someone climbing out of a pool. Calder glanced back, but didn’t see anything.

“If you have a better idea, I’m all ears.”

“You coming?” Duan said.

“Yeah,” Mitchell said. “We’re right behind you.”

“But if we’re dealing with polar bears, then why am I here?”

“They’re aquatic predators, aren’t they?”

A shuffling sound caused the hairs to rise on Calder’s neck. She peeked over her shoulder. Her beam barely penetrated the darkness, which felt as though it were staring back at her.

She hurried toward where Duan waited with the rope in his hand. All the way across, she could see Thyssen standing in the mouth of a tunnel, silhouetted against the pitch-black by his headlamp. What wasn’t he telling them?

Duan offered her the rope with a smile. She heard the slapping sound behind her again. Watched Duan look past her and his eyes widen in surprise.

“Go!” Mitchell shouted and shoved her out onto the arch.

She saw her foot strike the stone and far below it the river rushing past in the glow of her light.

Mitchell hit the bridge behind her. A cracking sound echoed like a gunshot.

The lights from the far side swung toward her, momentarily blinding her. She raised her hand to shield her eyes and felt the ground fall out from beneath her.

Mitchell struck her from behind as the limestone raced toward her. She saw the jagged, broken edge rising away from her and then the cold water pulling her down.

Nabahe watched helplessly as they struck the water and vanished into its depths. Chunks of limestone and debris rained down onto the river. It all happened so quickly. The three of them were there one second and gone the next.

He scurried to the edge and visually searched the river. It had to be a good thirty feet down. A section of the arch erupted from the water before disappearing again. He thought he saw a face gasping for air at the edge of sight, but it was gone before he could react. He pushed himself up and prepared to dive in after them.

“No!” Thyssen shouted and jerked him away from the ledge. “You stay here.”

“Can you see them?” Payton asked.

“What happened?” Hart said. “Why did they all go out there at once?”

Thyssen turned to Payton. “Can you belay me down there?”

Nabahe stared back across the broken bridge while Thyssen tied the rope to his harness. Why had they shouted and run like that? He hadn’t seen anything. He’d been focused on the tunnel ahead of them, through which he could swear he saw a faint glow. Until now, this had almost felt like a vacation. It was too easy to forget how dangerous formations like these were. Duan should have known better, though. What could have caused an experienced caver to run out onto a speleothem he knew couldn’t possibly support all of their weight at once?

The darkness beyond the mouth of the tunnel on the far side resisted his beam, which barely illuminated the orifice. The shadows shifted, or maybe it was just his imagination. He could have sworn he heard an almost guttural clicking sound that reminded him of the buzz of a rattlesnake’s tail.

Payton bellowed with the exertion. He leaned backward, braced his feet against the stalagmites, wrapped the rope around his hips, and used his own body as leverage to lower Thyssen over the river.

“Do you see them?” Hart shouted.

Thyssen twirled as he descended, until his feet were right above the water. He reached with his leg, found traction on solid ground, and pulled himself to the bank. The end of the rope hit the water and gave Nabahe an idea of just how fast the river was flowing.

Thyssen raised his hand to his mouth and appeared to whisper into his palm, then pressed both hands against his ears as though attempting to block out the sounds around him.

“We need to go in after them,” Payton said.

Thyssen shed his backpack and removed what looked like a tablet. It cast an eerie red glow. Nabahe could barely make out the pattern of dots on the screen.

“What are you doing?” Payton asked.

“Trying to figure out where they are.” Thyssen turned toward where the river flowed underneath a stone ledge, above which a delicate lattice of speleothems adorned the flowstone. “Each of these suits is equipped with a MINT transmitter. Micro-inertial navigation technology. It’s like GPS, only the signal doesn’t need to be routed through a satellite, so it works down here.”

“You put tracking devices in our suits?” Hart said.

“Would you rather we hadn’t? Without those transmitters, we wouldn’t have the slightest idea where they are right now.”

“Just tell us what you see,” Nabahe said.

“The signals are static and clustered together roughly a hundred and fifty feet to the northwest.”

“What does that mean?”

“Any number of things.”

Nabahe understood. They could have pulled themselves from the river and lay exhausted on the bank, or their bodies could have become lodged against some underwater obstruction. They wouldn’t know anything until either the bodies moved again or someone went in after them.

“They could be hurt,” Hart said. “Or worse.”

“Anchor the rope,” Payton said. “I’ll go.”

“We’ll never be able to pull you back out against that current,” Thyssen said. “Just give them a little more time to—”

Thyssen abruptly ceased talking.

Nabahe caught a glimpse of a red blur streaking across the monitor, then movement from the corner of his eye. He glanced toward the river in time to see a black shape speed past in its depths.

“We need to keep moving,” Thyssen said.

Despite the steadiness of his voice, Nabahe detected a flicker of panic in Thyssen’s expression when he hurriedly returned the monitor to his backpack, slung it over his shoulder, and leaped up onto the wall.

Payton barely grabbed the rope he’d used to belay Thyssen down before it slithered out of his reach and over the edge.