As Kaufman’s men turned the clearing into an armed camp, digging foxholes and bunkers, and unloading crates of weapons and ammunition from the helicopter, Norman Lang conducted his ultrasound tests, which confirmed a cavern beneath the temple and a tunnel linking the two. Not the vertical shaft of the well behind the altar, but a steep zigzagging passage that cut through the structure, like a switchback mountain road. It connected to a spot in the altar room, a spot that appeared to lie across the gaping mouth of the well.

Closer investigation revealed a fissure between two of the stones. Kaufman’s men forced the stone upward with a pair of crowbars, raising it an inch at a time, until it jammed against something and would budge no farther.

Lang wedged a two-by-four into the exposed space to brace the stone and then supervised the building of a makeshift bridge above the maw of the pit. He crawled across and peered into the tunnel, using a flashlight.

It was a narrow space, perhaps five feet high, but not much wider than a man’s shoulders. It fell away steeply, looking more like a slide than a walkway, and he saw evidence of a pulley and counterweight system for the stone, but whatever flaxen rope it might have once used had disintegrated long ago.

Minutes later, Lang was back in the tunnel, this time leading Susan Briggs and four of Kaufman’s hired guns. They moved cautiously, with each switchback seeming steeper than the last as the tunnel descended through the temple and into the ground below. Lang began to feel claustrophobic. In truth, he’d been feeling something similar since Kaufman had sucked him into this mess.

For several years he’d been Kaufman’s go-to man for risky projects, and in that time he’d come to realize that Kaufman sometimes used questionable methods to gather information, but he had never expected the events that he’d now become part of: shooting and killing and the taking of hostages. Lang was well aware that his own ego, greed and lack of discernable ethics had made him an easy mark, but this was far more than he’d bargained for.

Still, at this point, what choice did he have? No doubt any attempt to back out would result in an unpleasant end. No, he thought, crossing Kaufman outright would be foolish, especially out here in the jungle, surrounded by killers and thugs. Lang was a realist, at least in the sense of knowing what had to be done to survive, and for now that meant doing as he was ordered, trusting in the fact that Kaufman needed him to study and break down whatever items this project recovered. Once he made it back to the States, his approach might change, but for now he would do what was necessary—and if bodies were left behind, that would be okay as long as his wasn’t among them.

He turned to Susan. “How much farther?”

She stared at him blankly through the plastic of the gas mask. “How would I know?”

Of course she wouldn’t know. It was a stupid question. Why the hell was he even talking to her? He pushed on, sliding and crouching and feeling the burn in his legs—until he stepped out into an open space, a massive chamber where the ceiling pulled up and out of view and the edges ran away from them on either side. It was a deep and echoing place, like a darkened, empty stadium. Words of awe wafted through the air, echoing back at them while their lights skated dimly over distant walls.

They stood far beneath the temple. Directly ahead them lay a wide pool of utterly still, crystal-clear water: a small lake that stretched across the cave for perhaps a five hundred yards. There appeared to be additional land on the far side.

Lang pulled an ELF radio from his belt. ELF stood for Extremely Low Frequency, which was far more adept than standard frequencies at penetrating resistance. The Navy used a similar system to communicate with submarines a thousand feet below the surface. Lang and Kaufman hoped the orange radio with the long antenna would be powerful enough to send a signal through the rock. “We’re at the opening of the main cave,” Lang said, holding down the talk switch, “a good part of which is filled by water.”

Kaufman’s reply came back garbled. “Understand you … a large … filled with … -ter.”

“Affirmative,” Lang replied. There was no answer. He wasn’t sure if Kaufman had received or not. It didn’t matter; they would proceed, complete their preliminary search and then head back out.

As part of that search Lang filmed the area with his camera, repeating his black-light test and performing a few tests with a battery of other devices he carried. Finding nothing of interest, he looked across the water. On the far side of the lake he saw what appeared to be a raised area. Their lights barely reached it but it looked flat and level, unlike the rest of the cave. “We’ve got to find a way across,” he said. “Either that or we’re going to need a boat.”

A quick search revealed a pathway running along the right-hand shore of the lake, and they followed it, sticking to the edge of the water for the first part of the route, with a detour between a forest of stalactites and a formation of what looked like giant mushrooms made of wet stone. Past this outcropping, the path turned back toward the lake and became a narrow strip pinned between the water and the cavern wall. Finally, near the other side at last, it turned outward and crossed the very corner of the lake on what appeared to be a man-made dam. On the right side of the dam lay a group of small pools, arranged in a honeycomb formation. On the left side was the lake.

Lang taped the area with the camcorder. “I count seven of them.”

The circular pools measured about ten feet across. They were divided from one another by retaining walls of the same height as the dam. The water level was identical in each of the pools, though it was several inches higher than that of the lake. Lang wasn’t sure what that meant beyond the fact that the water must flow freely between the group of pools but not between the pools and the lake.

He filmed the formation but the unmoving, black waters gave away little.

“Some kind of construction,” Lang said for the video. “The same type of stone as the dam,” he noted. “Polished stone. Almost ceramic, or volcanic perhaps. No indication as to what they’re for.”

One of Kaufman’s hired soldiers looked at Lang with a smile, then turned to his friends. “Jacuzzi,” he said.

As the others laughed, Lang spotted a more promising site, a recessed area with a wide expanse of flat, smooth stone, a plaza of sorts that had clearly been worked and leveled with tools. “That’s where we need to go,” he said.

Lang traversed the dam with Susan and the mercenaries trailing out behind.

One of the soldiers stopped. “Wait,” he said, training his flashlight more closely on one of the pools. “There is something in there.”

“What do you see?” Lang asked, quite sure it would be nothing of consequence.

“A reflection,” the man said. “Something shiny.”

One of the other mercenaries came up beside the first one. “Munzen,” he said. “Gold munzen.” German for gold coins.

Lang looked at Susan for an explanation.

“The Maya often dumped things in wells,” she told him. “Sacrifices to their spirits. The sinkholes in Mexico are full of offerings. But those are deep, natural structures, not little pools like these.”

“What kind of things did they dump?” one of the soldiers asked.

Lang began to answer but Susan spoke first. “Jewelry and pottery, for the most part, sometimes even people.”

“What about gold?”

“The Maya didn’t have much gold,” Susan said.

The two mercenaries chuckled at that. “Gold, for sure,” the first one said. “Why else would we be here?”

The other mercenaries gathered around separate pools, as if they were staking their own claims. Lang shrugged. How could he fault these men for gold fever when he and Kaufman were after riches of their own? He decided to take a closer look himself and moved to one of the pools in the rear of the formation, around the curve and farthest from the end of the dam.

The soldiers began talking excitedly among themselves. The one who’d first spotted the reflection was wasting no time. His boots and shirt were already off. “I’m going in,” he said.

He undid his belt, and then tore off his pants and underwear without the slightest hint of modesty.

Susan turned away, blushing. Lang wondered if he should be filming. “Europeans,” he said, laughing.

The naked German stood at the edge of the pool, bringing his arms up as if he might do a swan dive. At the last minute he seemed to decide against it and his friends howled in disappointment. “Looks cold,” he said.

Lang turned his gaze back to the well in front of him. He focused his flashlight on it but didn’t see much, certainly nothing metallic. He picked up his camcorder and positioned it on his shoulder. The spotlight was more powerful than his flashlight.

The German was ready to jump now, feet-first.

Lang ignored him, aimed the camera and switched on the floodlight. For a second, the light reflected off of the water and blinded him, but he quickly changed his aim and the glare went away.

On the dam, the others egged their comrade on.

Lang adjusted his lens and the focus cleared, but all he saw was a trail of minuscule bubbles, like the carbonation in a glass of undisturbed soda water. At the sound of a splash, he looked up.

The mercenary had finally jumped in. Holding his nose, he’d plunged in feet-first, to a roar of delight from his friends. He came up seconds later, exhaling a great burst of spray—which quickly became a scream.

For a moment the others laughed, remembering his comment about the water looking cold, but the scream didn’t stop and the man thrashed around violently, eyes shut, frantically searching for the side of the well. His friends froze in their tracks, confused. When they finally realized his trouble was real, they ran to help him.

The man had reached the edge of the pool now. He tried to pull himself out, but the dam’s polished surface offered nothing to grab on to. The others reached for him, clutching his arms and pulling. But he slipped free, shaking violently and screaming.

“What’s happening to him?” Susan yelled.

The soldiers ignored her. One of them stretched out over the water, grabbed the man by the hair and yanked him back to the edge. The others pulled him out of the water and up onto the dam, where he lay, shuddering and convulsing.

His friends stepped back, looks of horror on their faces; the man’s skin was dissolving, melting away from his body, bloody foam oozing from his legs and waist as the rest of his skin blistered before their eyes.

They began to shout at one another, wiping their hands on shirts and trousers, anything they could find, their own skin burning. One grabbed a canteen and poured its contents onto his hands. “Wasser,” he shouted. The others followed suit, attempting to dilute the corrosive water that had splashed onto them.

As the soldiers frantically washed their hands, they moved away from their comrade, and Susan Briggs caught sight of him for the first time. She fell to her knees and gagged, expecting to be sick. She pulled at her mask, desperate to get it off as she suddenly recalled McCarter talking about a pool of acid. She hadn’t seen it. She hadn’t remembered or made the connection.

Sixty feet away, Lang stood transfixed. He could see the soldier rocking in spasms on the floor, shaking as if an electrical current was running through his body and choking on his own tongue as it swelled in his mouth from the caustic water he’d swallowed.

His friends moved toward him one moment and then away the next. One of them picked up his rifle and aimed it, apparently intending to put the man out of his misery, but another soldier held up a hand to stop him. The convulsions had begun to lessen.

Lang watched almost to the end before he found the strength to shut his eyes and turn away. He took a deep breath and opened his eyes again, focusing on the placid black pool in front of him. This time he saw something else besides the thin trail of bubbles: not gold as the dying soldier had seen, but green. A small green disk; two actually. They were eyes.

Black Rain