Tucker leaned to look where he pointed. The bulbs and the edges of the mushrooms that touched the wall were a brownish black, as if burned by the glow of the lichen covering the wall.

“I think the lichen is producing something toxic to the LUCA.” Bukolov swung toward Tucker. “Here might be the secret of the kill switch.”

Tucker felt a surge that was equal parts relief and worry.

Bukolov continued. “It’s what I had hoped to find here. Something had to be holding this organism in check down here. It couldn’t just be the isolation of the environment.”

“Then collect samples of everything and—”

Bukolov knelt back and brushed his fingertips across the roof, causing the glow to darken where he touched. “You don’t understand. We are looking at a microcosm of the ancient world, a pocket of the primordial history. I have so many questions.”

“And we’ll try to answer them later.” Tucker grabbed Bukolov by the elbow and pointed from the collection kit over the man’s shoulder to the field of growth. “Get your samples while you still can.”

A sharp bark echoed to them—followed by a second.

Kane.

“Get to work, Doc,” he ordered. “I’m going to find out what’s going on.”

Hurrying, he slid and crawled his way through the field of artillery shells and back to the waterfall chamber. He hauled himself out of the hole, and Christopher helped him to his feet.

“He just started barking,” Christopher said.

In the pool of light cast by the single LED lamp, it appeared Anya hadn’t moved. She was still tied securely. Kane stood next to her, but he was staring toward the twin shotgun tunnels.

“What is it?” Christopher asked.

“I don’t know. Kane must have heard something.”

Tucker remembered his earlier sighting of the Russian soldiers.

Anya called over to them. “It seems we owe you some thanks, Captain Wayne. We wouldn’t have thought of this method without you. Upon your example in Russia, we decided to add another weapon to our arsenal.”

She was staring at Kane.

Tucker suddenly understood her veiled implication.

Damn it, Anya, you are good.

The thought had never occurred to him. Barring technology, what was the best way to track someone?

Kane glanced back at him, clearly waiting for the order to pursue whatever he had sensed.

Tucker turned to Christopher. “Stay here and be ready to help Bukolov.”

“Is there trouble?”

Isn’t there always?

He pointed to Anya. “She moves . . . you shoot her.”

“Understood.”

Working quickly, Tucker crossed to their gear and prepared for the storm to come. He grabbed two spare magazines for his rifle, along with a red flare, stuffing them all into his thigh pockets. He then slung the AR-15 over his shoulder and picked up the Rover’s plastic gas can.

Once ready, he headed for the tunnels with Kane on his heels.

It was time to test these old Boer defenses.

11:55 P.M.

Reaching the Cathedral, Tucker hurried across the stalagmite maze to the series of sandbag walls at the far end. He hurdled over the first two with Kane flying at his side—then he skidded to a stop at the third wall and dropped to his knees.

Echoing up from the crooked tunnel ahead, he heard a faint barking.

No, not barking—baying.

The enemy had come with hounds.

Kharzin must have sent his main body of troops, along with the dogs, straight to where he had hid the booby-trapped Range Rover. The other Russians—the ones he had spied upon earlier—were likely a smaller expeditionary force sent here to canvass the side trail as a precaution. No wonder they had seemed so lax and casual. But now that Tucker’s trap had been sprung and his ruse discovered, Kharzin had returned here, bringing all his forces to bear.

But what was Tucker facing?

Only one way to find out.

He pointed to the tunnel. “QUIET SCOUT.”

Kane jumped over the sandbags and dove into the shaft. Using his phone, Tucker monitored his partner’s progress. Once Kane reached the straight corridor, Tucker touched his throat mike.

“HOLD. BELLY.”

Kane stopped and lowered himself flat, well hidden by rubble.

Right now the corridor appeared empty with no evidence of trespass. The pile of rocks blocking the way outside looked untouched. So far, the hounds hadn’t found this back door to the cavern system—at least not for the moment. But they would.

Through Kane’s radio, the baying already grew louder.

Hurrying, Tucker began removing sandbags from the middle of the barricade. After creating a sufficient-sized hole, he wedged the gas can into the gap. He then replaced the sandbags, taking care to hide any trace of the can.

All the while, Tucker monitored the phone’s screen, using Kane to extend his vision. Movement drew his full attention back to the screen. In the gray-green glow of Kane’s night-vision camera, the slivers of light at the far end of the corridor began to break wider. More light blazed through as rocks were pulled away.

Shadows shifted out there.

They’d been discovered.

Tucker whispered to Kane, “QUIET RETURN.”

The camera jiggled as the shepherd belly-crawled backward. After retreating for a spell, Kane finally turned and came running back. Moments later, he emerged and hurdled the sandbags.

Good boy.

After rechecking the placement of the gas can, Tucker pulled out a flare and jammed it between a pair of sandbags near the bottom. For now, he kept it unlit.

He turned to his partner. “STAY.”

With a final rub along Kane’s neck, he stepped over the sandbags, planted his rifle to his shoulder, and ducked into the shaft. He crawled until he was at the last corner of the crooked corridor. He kept hidden out of sight, peeking around the bend with his rifle extended. He quickly dowsed his headlamp and flipped the scope to night-vision mode. With his eye to the scope, he waited.

The first Spetsnaz appeared, peeking out from the straight passageway, bathed in the moonlight flowing from the open door behind him.

Tucker laid the crosshairs between the man’s eyes and squeezed the trigger. The blast stung his ears. He didn’t need to see the man crumple to know he was successful.

Tucker ducked away and retreated as the bullets peppered down the shaft, likely fired blindly by the second soldier in line. He knew the enemy dared not lob or fire a grenade into such a confined space, or it risked collapsing the very tunnel they had come to find and ruin any chances of reaching the prize. As far as they knew, this was the only way inside.

Still, he never trusted the enemy to think logically.

Especially with one of their comrades dead.

So he fled on his hands and knees.

If nothing else, the ambush would give the others pause, force them to move slowly, but it wouldn’t last long.

He reached the end of the tunnel, regained his feet, and hopped over the first sandbag wall. Crouching down, he ruffled Kane’s neck and did a quick inspection of the gas can and flare. Satisfied, he headed back over the series of sandbag fences.

As he hopped over the last one, a booming cry echoed from the far side of the Cathedral.

It was Christopher, calling from the mouth of the shotgun tunnels across the way.

“Tucker . . . watch out!”

40

March 22, 12:18 A.M.

Groot Karas Mountains, Namibia

Kane let out a deep snarl, leaped to his feet, and took off across the Cathedral floor, heading in Christopher’s direction. For the shepherd to break his last command to stay could only mean one thing.

An immediate and real danger.

Tucker stared down the length of the dark Cathedral.

At the other end, a star glowed, marking Christopher’s headlamp.

Between here and there lay a gulf of darkness. Kane vanished into it. Tucker lifted his rifle’s scope and used its night-vision capabilities to pierce the blackness. Out there, he watched a figure dashing between the stalagmites. Kane rushed at full sprint toward the shape. The jittering flight of the other was difficult to track through the forest of tall rock.