“No,” she said with sudden forcefulness. “I’ll have time to rest…later.”

Gideon waited.

“You know what happened next. You lived through it, too. The constant moving, the poverty. The…men. I just couldn’t pull it together. My real life ended that day. Ever afterward I felt dead inside. I was a terrible mother. And you…you were so hurt.”

“Don’t you worry, I survived.”

“Are you sure?”

“Of course.” But deep within, Gideon felt a twinge.

Her breathing began to slow, and Gideon felt her grasp relax. Seeing she was going to sleep, he eased her hand from his and placed it on the bedcovers. But when he bent down to kiss her, the hand shot up again, grasping his collar with claw-like fingers. Her eyes pinned his and she said, with manic intensity: “Even the score.”

“What?”

“Do to Tucker what he did to your father. Destroy him. And in the end, make sure he knows why — and by whom.”

“Good God, what are you asking?” Gideon whispered, looking around in sudden panic. “Mom, you don’t know what you’re saying.”

Her voice fell to a whisper. “Take your time. Finish college. Go to graduate school. Study. Watch. Wait. You’ll figure out a way.”

Her hand slowly relaxed and she closed her eyes again, the air seeming to run out of her forever, like a final sigh. And in a way it was; she lapsed into a coma and died two days later.

Those were her last words, words that would resonate endlessly in his mind. You’ll figure out a way.

Gideon Crew emerged from the ponderosa pines into the broad field in front of the cabin. In one hand he carried an aluminum tube containing his fly rod; a canvas bag was slung over his shoulder, two trout inside, nestled in wet grass. It was a beautiful day in early May, the sun mild on the back of his neck. His long legs swept through the meadow, scattering bees and butterflies.

The cabin stood at the far end, hand-adzed logs chinked with adobe, with a rusted tin roof, two windows, and a door. A rack of solar panels poked discreetly above the roofline, next to a broadband satellite dish.

Beyond, the mountainside fell away into the vast Piedra Lumbre basin, the distant peaks of southern Colorado fringing the horizon like so many blue teeth. Gideon worked on “the Hill”—up at Los Alamos National Lab — and spent his weeknights in a cheesy government apartment in a building at the corner of Trinity and Oppenheimer. But he spent his weekends — and his real life — in this cabin in the Jemez Mountains.

He pushed open the cabin door and entered the kitchen alcove. Shrugging off the canvas bag, he took out the cleaned cutthroat trout, rinsed them, and patted them dry. He reached over to the iPod sitting in its dock and, after a moment’s reflection, dialed in Thelonius Monk. The percussive notes of “Green Chimneys” floated from the speakers.

Blending lemon juice and salt, he beat in some olive oil and freshly cracked pepper, then basted the trout with the marinade. Mentally, he checked off the rest of the ingredients of truite à la provençale: onions, tomatoes, garlic, vermouth, flour, oregano, and thyme. Gideon usually ate only one real meal a day, of the highest quality, prepared by himself. It was an almost Zen-like exercise, both in the preparation and the slow consumption. When further sustenance was necessary, it was Twinkies, Doritos, and coffee on the run.

After washing his hands, he walked into the living area and placed the aluminum fly-rod case into an old umbrella stand in one corner. He flopped down on the ancient leather sofa and kicked his feet up, relaxing. A fire, lit for cheeriness rather than warmth, crackled in the large stone fireplace, and the afternoon sun threw yellow light across a pair of elk antlers hanging above it. A bearskin rug covered the floor, and old backgammon and checkers boards hung on the walls. Books lay strewn about on side tables and stacked on the floor, and a wall of shelves at the far end of the room was crammed with volumes stuck in every which way until no space remained.

He glanced toward another alcove, covered by an improvised curtain made from an old Hudson’s Bay point blanket. For a long moment, he didn’t move. He hadn’t checked the system since last week, and he felt disinclined to do it now. He was tired and looking forward to dinner. But it had been a self-imposed duty for so long that it was now a habit, and so at last he roused himself, raked back his long straight black hair with one hand, and slouched over to the blanket, from behind which came a faint humming sound.

He drew back the curtain with some reluctance, the dark space releasing a faint smell of electronics and warm plastic. A wooden desk and a rack of computer equipment greeted his eye, LEDs blinking in the dimness. There were four computers in the rack, of varying makes and sizes, all off-brand or generic, none less than five years old: an Apache server and three Linux clients. For what Gideon was doing, the computers didn’t need to be fast; they just had to be thorough — and reliable. The only brand-new and relatively expensive piece of equipment in the alcove was a high-performance broadband satellite router.

Above the rack was a small, exquisite pencil sketch by Winslow Homer of rocks on the Maine coast. It was the one remaining artifact from his previous profession: the one he simply hadn’t had the heart to sell.

Pulling back a ratty office chair on an octopus of wheels, he seated himself at the small wooden desk, kicked his feet up, dragged a keyboard into his lap, and began typing. A screen popped up with a summary of the search results, informing him he had not been in attendance for six days.

He drilled through to the results window. Immediately he saw that there had been a hit.

He stared at the screen. Over the years, he’d refined and improved his search engine, and it had been almost a year since the last false positive.

Dropping his feet to the floor, heart suddenly hammering in his chest, he hunched over the desk, banging furiously at the keys. The hit was in a table of contents released to the National Security Archives at George Washington University. The actual archival material remained classified, but the table of contents had been released as part of a large, ongoing declassification of Cold War documents under Executive Order 12958.

The hit was his father’s name: L. Melvin Crew. And the title of the archived, still-classified document was A Critique of the Thresher Discrete Logarithm Encryption Standard EVP-4: A Theoretical Back-Door Cryptanalysis Attack Strategy Using a Group of φ-Torsion Points of an Elliptic Curve in Characteristic φ.

“Mother of God,” Gideon murmured as he stared at the screen. No false positive this time.

For years, he’d been hoping for something. But this looked like more than something. It might be the brass ring.

It seemed incredible, unbelievable: could this be the very memo his father had written criticizing Thresher, the memo that General Tucker had supposedly destroyed?

There was only one way to find out.

Midnight. Gideon Crew slouched down the street, hands in his pockets, baseball cap turned backward, filthy shirt untucked beneath a greasy trench coat, baggy pants hanging halfway down his ass, thinking how lucky he was that today was trash day in suburban Brookland, Washington, DC.

He turned the corner of Kearny Street and passed the house: a shabby bungalow with an overgrown lawn surrounded by a white picket fence only partially painted. And, of course, a lovely overflowing trash can sat at the end of the walkway, a fearful stench of rotting shrimp hovering in the muggy air. He paused at the can, looking about furtively. Then he dove in with one hand, digging deep, groping among the garbage as he went. His hand encountered something that felt like french fries and he pulled up a handful, confirmed they were fries, tossed them back.