A river approach was likely because the mine’s southern boundary ran directly along the banks of the Arc River. There was even a bridge crossing the river nearby that looked like it went to an abandoned gravel pit that must have worked in conjunction with the mine when it was in operation.

Linc, Eddie, Linda, and Juan were in the conference room, studying the images projected on the big flat-panel monitors.

“Why a mine?” Lincoln asked suddenly.

The others were so deep in their own thoughts, no one had really paid attention.

“What did you say?”

“I said, why put this thing in a mine?”

That was something Cabrillo hadn’t given much thought to, so he had no answer. He called Mark down in his cabin and posed the question to him.

“It’s shielding,” he replied. “Eric and I had considered this when we first realized Bahar had built a quantum computer and were trying to guess a location. You see, the operations inside the machine take place at the atomic scale. It can automatically correct for atomic vibrations because they come at a set rate and frequency. One of the things that could unbalance the computer and cause it to kick out error messages is if it got bombarded by a heavy enough cosmic particle.

“As you know,” he went on, “the earth gets hit tens of trillions of times an hour by subatomic junk winging in from space. A lot of this is deflected by the magnetosphere, and what does get through is generally harmless to us. Though an interesting note, there is a theory posited that some cancers are the result of genetic damage caused by a single cosmic ray hitting a DNA strand.”

Juan knew to let him ramble but still had to grit his teeth.

“Anyway, on the exacting scales the computer works at, an impacting cosmic ray could disrupt the machine’s function catastrophically, so they need to shield it. Here’s the rub. I have no idea why they chose this salt mine. If cosmic radiation is a threat, we would have thought they would have buried it deeply under the densest rock they could find. The best theory Eric and I could come up with is, there might be some other mineral mixed in with the salt to help shield against one particular cosmic ray that would cause the most damage.”

“Okay, thanks,” Juan said, and ended the call before Mark could expound further.

“Sorry I asked,” Linc said sheepishly.

“Listen, why don’t we pick this up again when we have something more concrete to work with? We’ve got a good overview, but to plan the assault we need details.”

Heads nodded around the table, and the meeting broke up.

It wasn’t until after supper that Tiny arrived back aboard with Philip Mercer’s diagrams. Most of the crew were lounging around the dining room, some sipping brandy, others nibbling after-dinner cheeses. Cabrillo, who’d dined with Soleil, decided that this was as good a spot as any to take their first look at the plans and ordered the lights be set on bright. The clubby feel of the room lost some of its luster under a bright halogen stare.

Juan slipped out of his suit coat and loosened his tie. He fiddled with the cap of a Montblanc pen while he waited.

“Hey, gang,” Tiny called jovially when he entered the room. He wasn’t a regular feature aboard the Oregon, so his arrival was greeted warmly. The big pilot never looked so rumpled. His blond hair stuck out in tufts, and there wasn’t a square inch of his white uniform shirt that wasn’t rumpled. In his hand he carried a yellow legal pad and a single rose.

He crossed through the dining hall, shaking hands and slapping backs, until reaching the Chairman. “Tah-dah,” he said with a flourish, and set the pad on the table. He handed the rose to Soleil. “Mercer sends his compliments.”

She smiled.

Cabrillo spun the pad so he could see it. Mercer had written out a several-page description of the facility and the underground conditions. He detailed how over the years the miners had dug too close to the bottom of the river and that they refused to work the lower shafts. Roland Croissard had bought the facility during what he thought was a regular labor dispute. It was only after hiring Mercer and reading his report, and a report by another expert when he didn’t like what had been said in the first, that he realized he’d been swindled.

The first time he’d even visited the place was on the day Mercer delivered his report. Soleil had come with him on a lark.

Water seepage had been manageable, but Mercer calculated that the continued use of explosives deeper in the tunnels would cause the plug of rock between the mine and the river to fail. The flood would be catastrophically fast.

There was a gem among all the technical information, one that Mercer hadn’t disclosed to Croissard, and it was something he doubted many of the original miners remembered.

“There it is,” Juan blurted out when he read it.

“What do you have there?” Max asked. Unlike Juan, who had dressed for dinner, Hanley wore jeans and a western-style checkered shirt, complete with pearl snaps.

“One of the mine’s upper tunnels intersects with a piece of history.”

“Come again?”

“The miners bored their way into an old tunnel that was once part of the Maginot Line. Mercer writes that they had boarded it up, but he took the boards down and checked it out.”

Constructed after World War I as the ultimate defense for the homeland, the French had built a near-continuous wall of underground bunkers and forts along the border with Germany and, to a lesser extent, Italy. The forts had armored turrets that could pop up from the ground like obscene mushrooms and unleash directed cannon and mortar fire. Many of the structures were interlinked so that troops could be shuttled from one to another on subway trains. And some were so large, they were virtually underground cities unto themselves.

The Germans never obliged the French to use their grand fortification. When they invaded in 1940, they hooked through Belgium and Holland and poured into France where the defenses were weakest.

Because the Arc River Valley lacked the strategic protection of the mountains that surrounded it, it was little wonder that the French would have built casements and bunkers there.

“Does he say if he could reach the topside outlet?” Linda asked.

“No. He said he didn’t go that far. But it can’t be too tough to find.”

“I think,” Mark said, “that the bunkers that weren’t turned into museums and tourist attractions were permanently sealed by the French. Just so you know.”

“We can cut our way in with Hypertherm,” Max rebutted confidently. “Like how we cut apart that tanker. What was her name?”

“The Gulf of Sidra,” Juan answered with a shudder. He’d still been aboard when the steel-cutting explosive had burned through the hull like a wire garrote through cheese. He got back to the topic at hand. “This is our back door into the mine in case we need it.”

What followed in the legal pad were hand-drawn plans of each of the mine’s twenty-eight levels. They showed how the salt was excavated in huge rooms where massive pillars had been left in place to support the weight of the rock above. Mercer included information about ventilation shafts and water-removal conduits.

“The level of detail is beyond belief,” he said as he flipped though the pages.

“He has a photographic memory,” Soleil said. “We talked about his work, and he told me he remembers the layout of all the mines he’s ever entered.”

“This information’s a gold mine.” Cabrillo turned to Mark and Eric, who sat next to each other across from Max and Linda. “You guys think Bahar will put the computer on the lowest level?”

“Close, but that mine’s been inactive for years. More than likely the bottom levels have flooded due to groundwater seepage.” Mark cocked his head as he ran some esoteric numbers through his brain. He looked at Soleil. “How long ago did your father buy the mine?”