The Judas Strain (Sigma Force 4)

They continued alongside the lake.

Ahead, a small spit of stone projected into the water, barely discernible in the darkness. Only the encroaching tide of milky water revealed the small peninsula.

Along with something more.

"Are those bones?" Kowalski asked, staring down into the water alongside their path.

The party stopped.

Lisa crossed to the pool's edge. The soft light penetrated deep into the crystalline water. The stone bank fell away at a gentle angle through the water, then vanished over a steep lip ten yards out.

All across the shallow bottom of the lake, bones lay in mounds and piles: fragile bird skulls, tiny rib cages of monkeys, something with a pair of curled horns, and not far from shore, the massive skull of an elephant, resting like a white boulder below, one ivory tusk broken to a nub. But there was more: broken femurs, longer tibias, larger cages of ribs, and like a scattering of acorns, skull after skull.

All human.

The lake was a massive boneyard.

Stunned to silence, they continued onward.

As they hiked along the stone bank, the glow slowly grew in the lake. The burn to the nostrils that Lisa had noted before grew more intense. She remembered Christmas Island, the tidal dead pool on the windward side.

Biotoxins.

Kowalski wrinkled his whole face.

And like smelling salts, the sting also stirred Susan. Her eyes fluttered open, glowing in the dark, a match to the shine in the lake. She remained dazed, but she recognized Lisa.

Susan tried to sit up.

Gray and Kowalski lowered her to the floor, needing to rest anyway, stretching their shoulders and kneading their hands.

Lisa sank beside Susan, modestly draping the tarp over her shoulders as she helped the woman sit up.

Susan shied back as Kowalski stepped near.

"It's all right," Lisa assured her. "They're all friends."

Lisa introduced the others to help reassure Susan. Slowly the panicky daze cleared. She seemed to collect herself—until she stared past Lisa's shoulders and spotted the glowing lake.

Susan surged away, hitting the wall with her back and propelling herself up into a teetering crouch.

"You must not be here," she keened, voice rising.

"No f**king kidding," Kowalski griped.

Susan ignored him, her eyes on the lake. Her voice lowered. "It will be like Christmas Island. Only a hundredfold worse . . . trapped inside the cavern. And you'll all be exposed."

Lisa did not doubt it. Already her skin itched.

"You must go." Susan steadied enough to gain her feet, leaning a hand on the wall. "Only I can be here. I must be here."

Lisa saw the fear shining in her eyes, but also the dread certainty.

"For the cure?" Lisa said.

Susan nodded. "I must be exposed one more time, by the source here. I can't say how I know, but I do." She lifted a palm to the side of her head. "It's. .. it's like I'm living one foot in the past, one foot here. It's hard to stay here. Everything is filling me up, every thought, sensation. I can't turn it off. And I... I feel it expanding."

Again the fear shone brighter in her eyes.

Susan's description reminded Lisa of autism, a neurological inability to shut off the flow of sensory input. But a few autistic patients were also idiot savants, geniuses in narrow fields, their brilliance born out of their rewiring. Lisa tried to imagine the pathophysiology that must be occurring inside Susan's brain, awash in strange biotoxins, energized by the bacteria that produced the toxins. Humans only used a small fraction of their brain's neural capacity. Lisa could almost picture Susan's EEG of her brain, afire, energized.

Susan stumbled to the water's edge. "We only have this one chance."

"Why?" Gray asked, stepping alongside her.

"After the lake reaches critical mass and erupts with its full toxic load, it will exhaust itself. It will take three years before the lake will be ready again."

"How do you know that?" Gray asked.

Susan glanced to Lisa for help.

"She just knows," Lisa answered. "She's somehow connected to this place. Susan, is that why you were so urgent about getting here?"

Susan nodded. "Once opened to sunlight, the lake will build to a blow. If I missed it. .."

"Then the world would be defenseless for three years. No cure. The pandemic would spread around the world." Lisa imagined the microcosm aboard the cruise ship expanded across the globe.

The horror was interrupted by Seichan's return, pounding up to them, breathless, her face shining damply. "I found a door."

"Then go," Susan urged. "Now."

Seichan shook her head. "Couldn't open it."

Kowalski pantomimed. "Did you try giving it a hard shove?"

Seichan rolled her eyes, but she did nod her head. "Yes, I tried shoving it."

Kowalski threw his hands high, surrendering. "Well, that's all I got."

"But there was a cross carved above the stone archway," Seichan continued. "And an inscription, but it's too dark to read. The words might offer some clue."

Gray turned to the monsignor.

"I still have my flashlight," Vigor said. "I'll go with her."

"Hurry," Gray urged.

Already the air was getting difficult to breathe. The glow in the lake had spread far, sliding along the length of the spar toward shore.

Susan pointed to it. "I must be out on the lake."

They headed toward the peninsula of rock.

Gray paced Lisa. "You mentioned a trespassed biosystem earlier. Mind telling me what the hell you think is really going on here?" He waved to the glowing lake, to Susan.

"I don't know everything, but I'm pretty sure I know who all the key players are."

Gray nodded for her to continue.

Lisa pointed to the glow. "It all started here, the oldest organism in the story. Cyanobacteria. Precursors to modern plants. They've penetrated every environmental niche: rock, sand, water, even other organisms." She nodded to Susan. "But that's getting ahead of the story. Let's start here."

"This cavern."

She nodded. "The cyanobacteria invaded this sinkhole, but remember they needed sunlight, and the cavern is mostly dark. The hole above was probably even smaller originally. To thrive here, they needed another source of energy, a food source. And cyanobacteria are innovative little adapters. They had a ready source of food above in the jungle . . . they just needed a way to get to it. And nature is anything if not ingenious at building strange interrelationships."

Lisa related the story she had once told Dr. Devesh Patanjali, about the Lancet liver fluke, how its life cycle utilized three hosts: cattle, snail, and ant.