Sophia looked impressed. “Good idea.” She donned one of the plastic helmets, Chase grunting as he tried to force the other onto his head. Nina took a third hard hat as Chase set off.

He was briefly worried that he might have lost track of Fang, but the other Land Cruiser came back into view once they were past the marquee and the neighboring stage. They didn’t seem to be attracting any undue attention from the mine workers they passed.

Chase followed Fang’s vehicle, keeping down to the thirty-kilometer-per-hour speed limit and staying well clear of the passing dump trucks. When they approached the road leading to the airfield, he was surprised when Fang didn’t turn onto it. “Hello, where’s he going?”

Nina followed the path of the road. “Down into the mine, it looks like.”

Chase reduced speed slightly as he continued after Fang, not wanting to get too close. Not that it would be possible to hide that he was following him-apart from the giant trucks, there was little else in the way of traffic. He looked at Sophia. “What’s down here?”

“I have no idea,” she said. “Wearing a hard hat doesn’t make me an expert in diamond mining.”

They continued down the long spiral deeper into the pit. The dump trucks took the longest, shallowest route, but Fang guided his 4×4 down steeper inclines cutting between levels. Chase followed a few hundred yards behind. They were getting close to the bottom of the crater, which was a scene of constant mechanized activity.

Giant mobile excavators, dwarfing even the dump trucks, tore away at the walls of the pit with enormous rotating scoops resembling the blade of a circular saw. The rubble was transported back along conveyors to be collected in hoppers, which then spewed out hundreds of tons at a time into the back of each waiting truck. The noise was horrendous, and clouds of dust swirled in the vortex of wind caused by the crater itself. “Jesus,” said Chase, carefully following Fang’s path between the colossal machines. “They should have these on Robot Wars.”

“Just don’t get too close,” Nina said, cringing at the thump of rock on metal as a boulder larger than their Land Cruiser dropped into the back of one of the trucks. “I don’t want to end up as a red spot on somebody’s wedding ring.”

“A literal blood diamond,” commented Sophia, making Chase laugh. Despite all her other concerns, Nina couldn’t help feeling annoyed that she hadn’t thought of the joke first.

It had been awhile since she’d made him laugh…

All such thoughts vanished in an instant when Chase said, “He’s stopping.” She squinted through the patina of dirt now smearing the windshield to see the other Land Cruiser pull up by a tunnel entrance at the muddy bottom of the pit, away from the roaring machines.

“A mine shaft,” said Sophia, puzzled. “Why would there be a mine shaft? This is an open-cast mine.”

“I thought you weren’t an expert,” Nina said, hardly concealing her sarcasm.

“I’m not, but I do know the definition of ‘open-cast.’” Sophia’s tone was similarly derisive. “This shouldn’t be here.”

“Well, it is,” Chase stated, “and he’s going into it.” They watched as Fang, still holding the briefcase, put on a hard hat and went quickly to the tunnel entrance, where he was met by another man. They exchanged words, then disappeared inside.

Chase stopped next to Fang’s 4×4. “So, what do we do? Wait for him to come out so we can grab the map, or go in after him?”

“We go in,” Sophia said firmly. “Whatever’s in there, it must be connected to whatever my husband’s doing. It’s too out of place to be a coincidence. And Fang might have gone in there to give the pages to someone else. If we lose track of them, we may never get them back.”

“All right. But you two should wait for me in here.”

“I don’t think so,” Nina protested, pointing at the excavators.

“What if the foreman comes over to ask what we’re doing? If someone calls for security, we’re screwed-there’s only one way out of this hole.”

Chase nodded begrudgingly. “Okay, okay. Just… be careful. And if it looks like there’s going to be any trouble, run right back to the car and get out of the pit.”

“What, and leave you behind?” said Nina.

He took out his gun and gave her a patronizing look. “I can take care of myself.”

“And I can’t? Not that I had much choice the other day, seeing as how you’d run off to the other side of the planet-”

“I don’t think this is the appropriate time,” Sophia interrupted sharply. She opened her door and stepped out, forestalling any further discussion. Chase frowned at Nina, then got out himself.

Left alone, Nina banged her fists on her seat in exasperation before she too exited the Land Cruiser.

The tunnel entrance before her was about ten feet wide, an almost perfectly circular hole disappearing into the dusty brown earth. Faint, widely spaced lights hung from the ceiling. It brought back unpleasant memories of the tunnels beneath New York. She tensed at the thought.

“You all right?” Chase asked. He put a hand lightly on her arm.

“I’m fine,” she said, shrugging him away and shouldering her backpack. “Come on. Let’s get my map.”

Chase led the way, using the wooden props supporting the tunnel as cover to check ahead. Fang and the other man were already lost in the darkness.

The ceaseless noise of the excavators faded as they went deeper underground, but Nina heard more mechanical clamor ahead.

“At least nobody’ll hear us coming,” Chase remarked. He could see lights in the distance, a larger space that was the source of the rumbling. Fang and his companion were briefly silhouetted against the electric glare, then they rounded the far end of the tunnel and passed out of sight. “Okay, I think we can move now. But keep to the sides, just in case.”

He increased his pace to a jog, every so often looking back to make sure nobody had entered the tunnel behind them. It didn’t take long for them to reach the other end.

Chase warily peered around the last prop to see a large rectangular chamber. Three more circular tunnels led in different directions deeper underground. How they had been dug was now obvious; a large boring machine squatted on caterpillar tracks near the chamber’s center, its complex array of interlocking conical drill heads covered with jagged metal studs to rip apart the rock and earth.

But that wasn’t the machine responsible for the noise.

Conveyor belts emerged from each of the three tunnels, depositing the clumps of rubble they carried onto a single, broader conveyor that ascended almost twenty feet in the air to feed a huge crusher below. The pulverized ore then entered what Chase took to be some kind of processor. He couldn’t see what went on inside it, only that most of the ore was discarded, spat onto a large pile in one corner of the chamber. Whatever was being mined ended up in black metal drums, a number of which were arranged on a pallet.

Behind the whole affair were several portable cabins, stacked on two levels. A series of yellow-painted catwalks connected them to the crusher assembly.

“What the hell is this?” Chase wondered. “Why would you hide a diamond mine in a diamond mine?”

“I don’t think it has anything to do with diamonds,” said Nina. She crouched, using her thumb and forefinger to pry something out of the wall.

“Jesus,” Chase gasped. Nina held a stone about the size of a pea. It was rough, uncut… but unmistakable.

A diamond.

“I just saw it, right there.” She moved a few feet back down the tunnel, then pointed. “And there’s another one.”

“My husband always did brag about this being the richest mine in the country, maybe even the world,” said Sophia. “If diamonds are that easy to find, it seems he wasn’t joking.”