He shared a glance with Christopher and unfolded the papers. What he found there was written in both languages. Tucker read aloud from the English section.

“ ‘However unlikely this eventuality, if this message is ever found, I feel compelled by my conscience to recount what has led to the awful events that took place here. Whether our actions will ever be recognized or understood by our loved ones is for God to decide, but I leave this life confident that He, in His infinite wisdom, will forgive us . . .’ ”

The remainder of De Klerk’s testament went on for several more pages. Tucker read through it all, then folded the paper and put it back in his pocket.

“So?” Christopher asked.

He stood up. “Bukolov must hear this.”

38

March 21, 10:10 P.M.

Groot Karas Mountains, Namibia

With Kane leading the way, Tucker and Christopher made it back to the Cathedral. They had barely spoken after reading De Klerk’s letter. As they turned toward the double-barrel tunnels leading out from the cavern, Kane stopped ahead of them and turned. He gazed down the length of the Cathedral, toward the distant walls of sandbags. His ears were up, his posture rigid.

What had he picked out?

“QUIET SCOUT,” Tucker ordered.

Hunched low and padding softly, Kane took off across the former killing floor of the Cathedral. Tucker and Christopher followed, dodging through the forest of stalagmites. Near the end of the cavern, Kane leaped the sandbag barriers and stopped at the shaft leading out to the crooked corridor.

“HOLD,” Tucker ordered softly.

Kane stopped and waited for him.

Tucker took the lead, crawling through the twisting shaft of the corridor. He reached the end, where it straightened out. The slivers of pale moonlight blazed much brighter ahead. Then he heard it—what had likely caught Kane’s attention.

The faint rumble of a diesel engine.

Tucker picked his way along the last of the corridor. He dropped to his belly at the tumble of rocks. He peeked out one of the shining slivers and saw the canyon outside was lit up brightly from the headlamps of a truck parked in the canyon.

From that direction, a voice shouted in Russian.

Then a bark of laughter closer at hand.

A pair of boots stomped up to his hiding spot. A man, dressed in fatigues, dropped to a knee. Tucker froze, waiting for a shout of alarm, for gunfire.

But the soldier only tied up a loose bootlace, then regained his feet.

Tucker heard other men out there, too, moving about or talking quietly.

How many?

Then a deep baritone shouted harshly, gathering everyone back to the truck. A moment later, the timbre of the engine rose, rocks ground under turning tires, and darkness fell back over the canyon.

He listened, hearing the rumble fade slowly into the distance.

They were leaving.

These were clearly Kharzin’s men. Had they come to check out where the Range Rover had stopped for a few hours? Finding nothing here, were they continuing on to where Tucker had parked the booby-trapped vehicle, drawn by the transmitter?

Tucker placed his forehead against the cool rock and let out the breath he’d been holding. Relieved, he made his way back to Christopher and Kane. The three of them hurried back to the waterfall cavern.

Nothing had changed here.

Bukolov was where they had left him. Anya had rolled to her butt and leaned against a stalagmite, her arms still bound behind her. With her chin resting on her chest, she appeared to be asleep.

“How went the search?” Bukolov asked, standing and stretching.

“We need to talk,” Tucker said.

After ordering Kane to guard Anya, Tucker drew Bukolov to the mouth of one of the shotgun tunnels. He recounted their investigation, ending with his discovery of the charnel pit.

“What?” Bukolov said. “I don’t understand—”

“In that pit—staked to the wall of the shaft like a warning—I believe I found De Klerk’s missing pages.”

“What?” Shock rocked through the doctor.

Tucker passed the papers over. “He wrote this message in both Afrikaans and English. He must have been covering his bases, not knowing who might stumble upon that pit later: his fellow Boers or the British.”

“You read it?”

Tucker nodded. “De Klerk was terse but descriptive. About three weeks after they entered these caves, several men began getting sick. Terrible stomach pains, fever, body aches. De Klerk did his best to treat them, but one by one they began dying. In the final phase of the disease, the victims developed nodules beneath the skin of their lower abdomen and throat. These eventually erupted through the skin, bursting. While the British troops laid siege to the cave, De Klerk found himself overwhelmed by patients. As hard as he tried, he couldn’t find the source of the illness.”

“What then?”

“On day thirty, General Roosa ordered the remainder of the cave entrances sealed shut. He had become convinced everyone was infected—or soon would be—by some kind of plague. He was afraid that if the British breached their defenses they would also become infected, and the plague would spread to the outside world.”

“Not an unusual reaction,” Bukolov said. “Paranoia of pandemics ran rampant during the turn of the century. Scarlet fever, influenza, typhoid. It made normally rational men do crazy things.”

“I think it was more personal than that. According to De Klerk, General Roosa had lost his entire family to smallpox. Including his daughter Wilhelmina. He’d never quite gotten over it. According to De Klerk, the symptoms they saw among the men struck Roosa very close to home. It was too much like the pox that killed his family. In essence, the guy lost it.”

“So everyone died here. Despite what the records show, the British never did overrun this cave?”

“That record was likely falsified by the British colonel waging this siege,” Tucker said. “He came to kill Roosa and his men. And after what happened here, the end result was the same. Everyone dead. So the British colonel took credit and chalked it up as a victory.”

“Craven opportunist,” Bukolov muttered sourly, clearly bothered that history was so unreliable and anecdotal.

Tucker continued the story. “Shortly after Roosa and his Boers entombed themselves, the British left. The dead were dropped into the pit and burned along with their clothing, bedding, and personal belongings. Many committed suicide and were burned as well—including Roosa himself. De Klerk was the last man to go down, but before he lowered himself into the pit and put a gun to his head, he gave his diary to a passing Boer scout who discovered their hiding place. De Klerk took care not to contaminate the outsider. This was the man who returned the journals and diary to De Klerk’s widow.”

“And what about what he pinned to the wall of the pit?” Bukolov lifted the sheaf of papers.

“A warning for anyone who came here. On the last page of his testament, De Klerk lays out his theory of this disease. He thinks it was something the men ingested—small white bulbs that the soldiers thought were some kind of local mushroom. He even includes some beautifully detailed drawings. He wrote the name under them. Die Apokalips Saad.”

Bukolov’s eyes shone in the dark. “LUCA.”

Tucker nodded. “So it sounds like your organism infects more than just plants.”

“Not necessarily. You mentioned the worst of the victims’ symptoms were concentrated to the throat and abdomen. The human gut is full of plant material and plantlike flora. LUCA could thrive in that environment very well, wreaking digestive havoc on the host.”

“Does that mean LUCA poses a danger as a biological weapon, too?”

“Possibly. But only on a small scale. For humans to become infected, they would have to eat it or—like here—be confined in a closed space where airborne spores are concentrated.”