The 6th Extinction (Sigma Force 10)

“Professor,” Gray said, “we’re running low on diesel. How much farther is this Back Door substation?”

Harrington lifted his face, his complexion wan and tired, his eyes glassy with anxiety. It looked like he had aged decades during the journey from Hell’s Cape. “Not far. The Back Door is at the opposite end of the Coliseum. Can’t miss it.”

Something screeched loudly, then struck the top of the cruiser. Claws dragged along the roof—before falling away again.

We’d better reach it soon.

Harrington cast a worried glance toward his daughter—then leaned over, clutched Gray’s knee, and whispered with some heat. “If something goes wrong, you’ll get her out of here.”

“I’ll do my best,” he promised.

His words seemed to offer Harrington little solace. To distract the man, he sat next to him.

Gray motioned to indicate the bulk of the cruiser. “So what was Admiral Byrd doing down here?”

“I think he came looking for a secret Nazi sub base—and found this place instead. All I can say for sure is that he arrived in Antarctica in 1946, a year after the end of World War II. He was accompanied by thirteen ships, over twenty aircraft, and almost five thousand men.”

“Five thousand . . . why that many?”

“It was called Operation Highjump. The official story was that Highjump was a polar training exercise, coupled with a mission to map the continent, but most of his expedition’s objectives were kept top secret. It led later to a series of atomic blasts down here. I think the bigwigs who oversaw Byrd’s expedition had been trying to bottle this place up. It’s said that Byrd was never really the same after that expedition, that he was a changed man, more reclusive, sickly. Some blamed it on the time he spent alone on the ice years before, but I wonder if it wasn’t this place.”

One only had to stare at Harrington’s haunted, scared eyes to understand what he meant.

“Maybe we should never have found these caverns again,” the professor said. “Maybe we should have heeded Darwin’s wisdom to keep this secret buried and untouched.”

Kowalski hollered from up front. “Better come see this!”

The urgency in his voice drew them all to their feet. They piled up into the front cab. Harrington dropped heavily into the passenger seat.

Past the windshield, a vast swampland blocked the way ahead, flowing with streams, pools, and a scatter of waterfalls. The great petrified forest behind them dwindled down to a handful of lonely sentinels out there. Overhead, stalactites pointed down from the roof.

Across this swampland spread vast fields of the phosphorescent reeds, lighting even the darkness beyond the reach of their headlamps. Strange creatures moved everywhere across this macabre field. Wading birds took off on leathery wings, fleeing the arrival of the growling, smoking beast of a cruiser. Lumbering shadows slumped through the reeds, their presence only discernible by their passage. Along the banks, other creatures slithered, hopped, or crawled out of their way. All the while, screams, caterwauls, and piping songs pierced their steel cocoon, as if life down here continually challenged this noisy trespasser into their midst.

But none of this was what caused Kowalski to call out.

Gray gaped at the sight before him.

My God . . .

Throughout this flooded savannah moved a herd of massive beasts, a hundred or more in number, each the size of a woolly mammoth. They moved mostly on all fours, though occasionally one would rise up on its hind legs and lumber in an ursine fashion for a few steps, likely surveying its surroundings for danger, before dropping back down. Their faces had short proboscises, like dwarf trunks of an elephant. These prehensile appendages would snatch at the reeds, pulling them up and gnashing them slowly, methodically, like a cow chewing a cud.

“See that moss growing along their flanks,” Stella said.

Gray squinted. He had thought the great shaggy mats hanging from their muscular bodies were fur, like found on mammoths. Only this growth softly glowed in a kaleidoscope of colors.

“We believe the moss has a symbiotic relationship with these beasts, which we named Pachycerex ferocis. The Pachyceri use their body heat to trigger those changes in colors, using it as a way to communicate among the herd.”

“Like fireflies in a meadow,” Jason said, earning a smile from Stella.

Kowalski was less enamored. “Only looks like these fireflies could stomp you to death.” He glanced over to the professor in the neighboring seat. “What about us? Is it safe to continue?”

“Just go slow. The headlamps will likely confuse them enough to let us pass.”

For a species that communicated in soft glows, the herd probably thought the cruiser was yelling at them, like some tone-deaf and deformed member of their species.

“They’ve never truly bothered us in the past,” Harrington continued. “But I’ve never seen such numbers in one place. We’ve spotted a few here and there, and they leave us alone, especially if we stay brightly lit.”

“Maybe it’s mating season,” Stella said. “And this is their breeding ground.”

“In that case,” Kowalski said, “nobody out there better get the wrong idea about us and decide to put the moves on this boxy lady of ours. Getting flattened by a horny elephant is not the way I’m planning on dying.”

“Do what the professor says,” Gray warned. “Move out, but set a cautious pace.”

Kowalski grumbled under his breath as he put the cruiser into gear. They headed through the shallows, making a wide circling arc to stay clear of the deeper pools of the flooded terrain. The Pachyceri meandered out of their path, a few snorting at them, as if rebuking them for the rude intrusion. They rolled past one tall enough to peer into the side of the cab, eyeballing the strangers inside.

“Nosy guy,” Kowalski said, glancing back for approval. “Get it . . . nosy.”

Stella and Jason both groaned.

Gray kept a watch on the rearview mirrors, making sure none of the beasts decided to challenge them, worried that even the stout cruiser might not survive a full-on assault by one or more of these giant creatures.

As he kept guard, a flash of light caught his attention in the mirror, much brighter than the herd’s glow. It came from farther back, where the petrified forest grew thicker. Then he spotted another set of lights to the left, like a pair of xenon-glowing eyes. And a moment later, a third pair joined the other two.

Gray’s fingers tightened on the seatback in front of him.