The Devil Colony (Sigma Force 7)

She waved Kowalski forward. “C’mon. I’ll help you.”

With Painter prying the stone up, it took all three to grip the exposed edge and pull the stone cork out of its hole. Balancing the slab up on its edge, Kowalski rolled it to the chasm wall and leaned it there.

“Satisfied?” he asked Nancy, brushing his hands on his pants.

She refused to respond and turned to the hole. Painter fished out a flashlight from his pack and pointed it down. The beam illuminated a wide shaft, angled steeply as it dropped away.

“They’re steps,” she said, awed.

Steps was a generous term. Carved into the rock were distinct footholds, not much larger than would hold a toe or heel. Still, it was better than nothing. They wouldn’t need ropes.

Kowalski joined them, leaning over the opening. “Phew.” He waved a hand in front of his face. “Stinks.”

Hank nodded. “Sulfur. And warm. Unusual for a blowhole.”

Must be some geothermal activity below . . .

A disconcerting thought, but they had no choice except to continue.

He turned to Nancy. “Would you mind waiting here? If we’re not out within two hours, radio for help.”

She nodded.

“But please give us those two hours,” he stressed, fearing that as soon as they were gone, she’d call her friends at the park service.

“I gave you my word,” she said. “I’ll keep it.”

With his tail tucked between his legs, Kawtch backed away from the hole. The smell and strangeness must have spooked the dog. Painter couldn’t blame him.

Hank held out his dog leash toward the ranger. “Could you keep an eye on Kawtch, too, while you wait?”

“I don’t think I have much choice. He’s not going down there. Probably the smartest of all of us.”

With matters settled, Painter made a quick call to Sigma command, letting Kat and Lisa know the situation here. Once this was done, he ducked and climbed down into the passageway, careful to plant the heel of his boot into each carved hold. He didn’t want to go sliding down to oblivion. He led the way, pointing his flashlight. Kowalski manned the rear with another light.

The tunnel continued down a long way. After several minutes, the hole to the surface shrank to a tiny sunlit dot far behind them. Ahead, the way grew hotter, the air more foul. Painter’s eyes and nostrils burned, an unpleasant sensation that was only exacerbated by the steady wind blowing in his face. He didn’t know how much farther they could go before they’d have to turn back.

“We must be deep beneath the mesa,” Hank estimated. “At least a hundred feet. Feel the walls. The rock has changed from sandstone to the limestone that underlies most of the Colorado Plateau here.”

Painter had noted the change, too. How far down does this go?

Kowalski must have wondered the same. He sucked loudly on the tube to his water pouch, then spat it out and swore. “If we come across a guy with hooves, carrying a pitchfork, we haul ass out of here, right?”

“Or even sooner than that,” Hank said, coughing on the bad air.

Still, Painter trudged onward, until a steady hissing and gentle roaring reached his ears. The beam of his light revealed an end to the tunnel.

Finally.

“Something up ahead,” he warned.

He continued more cautiously, crossing the last few yards, and pushed out into a cavity that was both wondrous and terrifying in its beauty. He moved out of the way so that the others could join him.

Kowalski swore as he stepped out.

Hank covered his mouth, offering up a small, “Dear God . . .”

The tunnel emptied into a large cavern, tall enough to house a five-story apartment building. Overhead, the roof was perfectly domed, as if the chamber had been formed out of a bubble in the limestone. Only this bubble had cracked long ago.

To the left, a wide fracture high up the wall allowed a river to gush forth, pouring down into the cavern in a turgid fall—but it was not a river of water. From the crack, black mud boiled and flowed, popping and spewing a sulfurous steam, as it ran thickly downward. It pooled into a great lake that filled half of the cavern, fed additionally from a dozen trickles weeping out of smaller fissures in the wall. The pool then emptied into a gorge that split the cavern. Down that chasm, a river of seething mud, bubbling and roiling, swept past, until it vanished down a dark gullet on the far side.

“Amazing,” Hank said. “An underground river of mud. This must be one of the geothermal arteries flowing all the way through the Colorado Plateau from the San Francisco range of volcanic peaks.”

But they weren’t the first ones to discover this giant artery.

An arched bridge, built of long, narrow slabs of sandstone, all mortared together, spanned the steaming gorge. The pattern and design were readily identifiable as the handiwork of the ancient Pueblo Indians.

“How did anyone build that down here?” Kowalski asked.

Hank answered, “The old tribes of this region were phenomenal engineers, capable of constructing extensive and complex homes halfway up sheer cliffs. This bridge would be easy for them to make. Still, they must have hand-carried each of those thin slabs down here.”

The professor’s eyes went glassy—either from the sting in the air or from imagining such an engineering feat. Hank moved forward. A jumble of broken rock littered the cavern floor, but some ancient hand had cleared a path to the bridge long ago.

Painter followed, knowing the professor’s goal. A similar path threaded from the far side of the span to a tunnel opening in the opposite wall. It seemed that their journey through this subterranean world wasn’t over yet.

As they approached the bridge, the heat spiked to a blistering degree. The air grew nearly impossible to breathe as its sulfur content swelled. The only reason they’d made it this far was that the continuing breeze sweeping through the cavern flushed the worst of the toxins up the shaft behind them.

“Do you think it’s safe to cross?” Kowalski asked, hanging back with Hank, who looked equally uneasy.

“This bridge has stood here for centuries,” Painter said, “but I’ll go first. Alone. If it looks okay, I’ll have you follow one at a time.”

“Be careful,” Hank said.

Painter intended to be. He stepped to the edge of the bridge. He had a good view down into the chasm. Mud bubbled and spat, splattering the limestone walls to either side of the gorge. It would be instant death to fall down there.

With little choice, he placed one foot on the span, then the other. He stood for a breath. Seemed solid enough, so he took another step then another. He was now over the gorge’s edge. Hearing sandstone grating slightly, settling a bit under his weight, he waited, swallowing his fear. Sweat trickled in streams down his back. His eyes watered and itched.