Links led Darling into his cubicle, a drab, sterile space. The only decorations were a 3-D topographical map of Oahu and, hanging from a thumbtack, a lipstick-smudged Chinese air-pollution-filter mask.

“So this is where the magic happens?” Darling asked dryly.

“There’s damn little magic happening here, I’m afraid,” said Links soberly. “We still don’t have much of a clue how they’re tagging our subs.” The opening missile strikes that had hit the Pacific carriers had been a shock to the fleet, but the way the enemy had found and destroyed the Navy’s submarines was a more disturbing mystery. The U.S. intelligence community had known the Chinese were catching up in surface-ship construction, but they believed that, under the sea, the U.S. had an asymmetric advantage. Ever since the Cold War, if an American sub didn’t want to be found, you couldn’t find it. But somehow the other side had figured out how to make the ocean transparent and thus deadly to the sub fleet that was supposed to give the U.S. its overwhelming edge.

Darling sat down and, picking up on Links’s sober mood, said quietly, “Tell me more.”

“I don’t even know where to begin,” said Links. “I keep thinking of what this lecturer once told us, back in training. He was old-guard CIA, had done Afghanistan both times, during the Cold War and then again after 9/11. He compared the intelligence task to solving a jigsaw puzzle, except that you didn’t get the box cover, so you didn’t know what the final picture was. And you got only a few pieces at a time, not all of them. And even worse, you always got a bunch of pieces from some other puzzle thrown in.”

“Start with the detection, and then the targeting,” Darling suggested.

“We spend all our time looking backward, trying to understand how,” said Links. “One argument is that the Directorate is using its own subs to shadow ours. And we just keep failing to detect them somehow.”

Darling stiffened in his chair as he recalled losing the John Warner to a Chinese ballistic missile.

“No way,” he said. “The Directorate sub we were following was too far away from the Warner to be able to get any kind of pinpoint tracking. And there were no transmission traces. If their sub had communicated the Warner’s position back to Hainan, we would have caught it. Besides, that sub was too busy running from us to do anything. About the time the Stonefish were firing, it was sinking. We got it, that’s one thing I am certain of.”

“Could they have used your comms to track the Warner, maybe even gotten into ATHENA?” asked Links. “Did you pick up anything like that?”

“Nope, nothing. Have you thought about big-data collection from environmental sensors, like how those fishermen kept detecting our Trident missile subs off Bremerton a few years back? Or what about space-based underwater detection? Tracking the IR or even something like the Bernoulli effect, from the water distortion?” said Darling. “Maybe a Ouija board?”

“We’ve run them all down. The sensor one is out, as you have to seed the area beforehand. There’s no trace of that, plus the Chinese are picking up our sub traffic everywhere, no matter where we go. The Oregon paid the price for us testing that theory off the Aleutians. Space-based detection is the working theory, but no one knows how the Chinese could manage that either. NAASW is looking at synthetic aperture radar as an option for undersea detection,” said Links. “During the Cold War, there were some attempts to make that work in tracking Soviet boomers, but nothing stuck. More important, they can’t cover an ocean area without broadcasting enough energy down from space that we’d pick it up.”

“How about the other way around?” Darling suggested. “How about magnetic detection of the sub’s hulls? That’s the working theory at the analysis section we have set up down at the B-ring urinal.”

“No, that’s another Cold War tech that was tried and failed,” said Links. “It just doesn’t work from space. There’s too much backscatter to pull out anything metallic at that range. They’d be plinking pretty much every piece of metal on the sea floor with Stonefish warheads. Plus, you also have the mystery of how they were able to track the subs and the carriers but couldn’t pinpoint the escort ships,” said Links.

“Maybe the escorts weren’t worth the trouble? Maybe the Chinese didn’t have enough missiles?” said Darling.

“No way. You think they’d try to save a few bucks if they could take out all of our Aegis ships?” said Links.

“So if that’s the case, it’s something that’s letting them track the nukes,” said Darling.

“Yep, which puts us at, as we call it in the intelligence community, square one,” said Links.

“So the real question is, what’s so special about a nuclear reactor?” said Darling. “If you want to find one from really far away, you have to be able to collect whatever it emits. But, shit, at range it’s never going to emit anything more than low-level Cherenkov rays.”

“What did you say?” Links asked with a catch in his voice.

“Cherenkov rays,” said Darling. “Did you sleep through the nuclear physics class at the Naval Academy? It’s what gives nuclear reactors their blue glow, something about charged particles passing through the medium that surrounds the nuclear reaction at different speeds than light. Some Russian named Cherenkov discovered them like a hundred years ago. He won the Nobel Prize for it.”

“Star Trek. You bastard,” whispered Links to himself. He tossed his wallet onto the desk with a shaking hand. “Lunch is on me. I’ve got to run, got an idea.”

“Whatever, man. Your DIA analyst better be worth it.” Darling picked up the wallet and was just beginning to stand when he heard the security door shut with a heavy thud.

“Ms. Shin, please, over here,” said the voice box, translating the guard’s Chinese into English. The guard was male, but the device had been set to speak in a digitized voice that matched the gender of the person being spoken to. Carrie wasn’t sure if it was a joke or if some Directorate scientist had concluded that if a woman heard a female voice coming out of a burly, armed male Directorate marine, she would somehow find it more reassuring than a male’s voice.

“Okay, okay,” Carrie said. She put her arms out and threw her head back, cruciform-style, her long hair reaching to her waist.

“We have selected you for extra assurance measures,” the marine said. He stood at about her height but had around twice her mass in muscle. The telltale acne and thick neck showed how he had gotten so big. So many of their marines had that look.

“Do you understand?” said the voice box.

“Yep,” said Carrie.

“The Directorate appreciates your compliance,” said the device. That was the latest phrase the voice boxes were spitting out. She couldn’t tell if it was what the guard had actually said or if it was just a stock phrase from an automated setting.

The chem swabs tickled when they ran down her arms and legs. It felt like a spider exploring her.

“I am complete,” said the voice box.

She opened her eyes. The swab had not turned red, as it would have if it had detected explosives. Instead, it was a light brown. The guard looked quizzically at the swab, unsure of what the earthy substance was.

“It’s okay,” said Carrie. “It’s makeup, from my arm. I cut myself cooking.” She ran her fingers across her cheeks as if putting on foundation and flashed a smile.

The voice box translated for the marine, who nodded, paused, and then muttered a phrase she could barely hear.

“Thank you for your compliance,” the box said. By this time the marine was looking to the next person in line.

She walked away slowly, calming herself, unconsciously rubbing the thin scabs on her arm. At least this check hadn’t been as bad as the checkpoint at the bus station; there, the guard made her bend over and speak directly into the voice box on his belt. She caught a glimpse of Waikiki Beach across the street and for a moment she found herself thinking of her fiancé, the sunset walk on his birthday. The wind had been up that night.