Page 135 of Chain Reaction

“Sure,” Julia said.

He picked her up and sat her in the crook of his elbow, soft and weightless. She looked all around, from her new and unaccustomed elevation. Julia got out behind her. She looked calm, but a little tentative. A little shell-shocked.

She said, “General Turner told me you need my help.”

“You OK?” he asked.

“Better than I was,” she said. “Surprised by today, mostly. Surprised is such a small word. Was this really my husband’s life? I didn’t know.”

“It wasn’t his life. He was a thinker. A lab guy. Which is why the fact he came here is so significant.”

Turner and Elwood joined them, a small group on the first yard of gravel. The sun was an hour from hitting the horizon. Amanda batted at Reacher’s hand. She gripped the tip of his forefinger. Less than an hour ago it had been crushing Hennessy’s carotid artery. The tiny soft fingers felt better.

“I have three things on my mind,” Reacher said. “First, we have no technical explanation, even after weeks of expert input. Second, EEF bought one data center but made cosmetic improvements to all five, which is absurd. Who does that? When you paint your house, do you paint four of your neighbors’ houses too? Third, they laid the gravel at night, which is equally absurd. Way more difficult and expensive than it needed to be. Why would they do that?”

“Tell us,” Elwood said.

“They laid the curb by day. The kid from the motel walked over and watched. Just innocent curiosity. He’s interested in what goes on in the neighborhood. But they couldn’t afford for him to see the gravel go down. They didn’t want to draw attention by threatening him or scaring him off, so they laid the gravel at night, while he was asleep.”

“Why?”

“Because the gravel hides the secret.”

“What secret?”

“I think they connected all five data centers together with physical wires.”

Turner looked at Julia Bisley.

“Is that possible?” she asked.

Julia paused a long moment.

“Kind of,” she said. “Not wires. It would have to be fiber. Not in parallel, either. Four centers would each need to feed the fifth. Sequential, like two-step daisy chains. Data packets can’t be in two places at once. They would need to flow from the first to the fifth, from the second to the fifth, from the third to the fifth, and so on. That way each packet would show up in two centers, first one, then the other, nanoseconds apart. Close enough to look like they were in two places at once. Which would be why our map came out the way it did.”

“OK, then,” Turner said.

“But it’s pointless,” Julia said. “Data is heavily encrypted. It would pass through, but they couldn’t do anything with it. They couldn’t read it.”

“Suppose they could?” Reacher said. “We know they hacked a system built by the NSA. Maybe they’re good enough to hack anything.”

“Also pointless because there’s nothing military here. I did some research. There are online communities who piece things together. Two of these centers are for A.I. algorithm training and three are for cryptocurrency mining. They’re all ASICs.”

“What does that mean?”

“It means they’re built with application-specific integrated circuits. Which means the chips are minutely customized for specific tasks, not for general-purpose use. They’re like fine-tuned race-car engines. Super powerful, but no good for driving to the store. These are not everyday server farms. No dusty old war plans are stored here.”

Elwood said, “How would they go about connecting the fiber?”

“It would be easy enough. They would disconnect what’s there and then connect the output port of center one to the input port of center five, and so on, all down the line. They’re physical connections, somewhat intricate, but with the right tools it’s straightforward. But all that is after they get inside. And how would they do that? There are four electronic gate locks and four electronic door locks in their way.”

“They would hack in remotely,” Reacher said. “You’ve seen them do it. They switched off the cameras in your building.”

“This is different. This isn’t some half-assed private landlord. If they bust this level of security, plus data encryption on the internet, plus systems built by the NSA, then they’re seriously elite hackers. Got to be top five in the world. Why would they be here, of all places? It’s a low probability.”

Reacher waved a come-here gesture to the kid in the snowplow, who climbed out and walked over.

Reacher asked him, “Remember the night they laid the gravel?”