“Four minutes,” said Krajcek.

Von Daniken traded concerned looks with Myer. The men continued with their search. Myer foraged through the boxes while von Daniken rooted around the papers on the drafting desks.

“Two minutes,” said Krajcek.

Just then, von Daniken remembered the initials in Lammers’s agenda. G.B. He looked at the back of the photograph again. The initials weren’t “C.E.” but “G.B.”

He brought up the photo he’d taken and used the in-camera zoom to read the phone number next to G.B.’s name. Area code 078. The Tessin, the country’s southernmost canton, where the cities of Lugano, Locarno, and Ascona were located. It was his first real lead.

It was then that he saw Kübler standing in the doorway. The man didn’t speak, but walked toward them like an automaton, his eyes fixed to the radiation detector. “RDX,” he said. “The place is thick with it.”

The initials required no explanation. RDX, short for Royal Demolition Explosive, was well known to any law enforcement official involved in counterterrorism. First developed by the British prior to the Second World War, RDX was the prime component in many types of plastic explosives, and the inciting charge used in all nuclear weapons.

Von Daniken felt as if he’d had the wind knocked out of him. A drone, a company that manufactured hyperaccurate guidance systems, and now plastic explosives. “But I don’t see any in here,” he protested. “Where could it be hidden?”

“It’s not here now. I’m just detecting traces. But the readings are fresh.”

“How fresh?”

Kübler studied the display. “By the rate of decay, I’d say twenty-four hours.”

Before Lammers’s dinner with G.B.

“Sixty seconds,” said Krajcek. “I have the watchman’s car three blocks away and closing.”

“Out,” said von Daniken as he furiously snapped photographs of the blueprints. Kübler hustled out of the workshop. Myer followed. Von Daniken moved to the door. It was as he was going to turn off the lights that he saw it.

A baby brother.

At the far end of the room, pushed back on a shelf beneath the counter, was a smaller version of the MAV in Lammers’s office, perhaps half the size-no more than twenty centimeters long, another twenty high. The wings, however, were cut from a different shape, nearly triangular. He observed that they were fixed to a central hinge and flapped up and down, like a bird’s wings.

Caught for a moment between staying and going, he rushed over and grabbed the miniature aircraft. The assembly weighed no more than five hundred grams. Not exactly light as a feather, but pretty damn close.

“Does it fly?” he’d asked Michaela Menz earlier that afternoon.

“Of course,” was the indignant reply. “We launch it from the loading docks.”

Von Daniken noted that the underside of the wings was covered with a light, tensile fabric that was colored a flashy yellow and patterned with a familiar black marking.

Myer pushed his head back into the office. “Goddamn it, man, what are you doing? We have to get out of here!”

Von Daniken held up the MAV. “Look at this.”

“Leave it!” Myer fired back. “What the hell do you want with a toy butterfly, anyway?”

Outside the city of Vienna, in the wooded hamlet of Sebastiansdorf, lights burned in the windows of Flimelen, a traditional Austrian hunting lodge. Built as a retreat for Emperor Franz Josef, the rambling estate had followed its owner to the grave at the close of the First World War. For forty years, it had sat abandoned and uncared for. Windows broken, doors pried loose for firewood, the stones of its foundation removed to build other, less majestic homes, it seemed to have been swallowed whole by the forest itself.

And then in 1965, it was reborn. From one day to the next, workmen arrived and began to restore the decrepit building. New windows were put in. Sturdy doors installed. Farther down the road a guard post was built. Needing a secluded getaway in which to discuss its most confidential affairs, another organization had claimed Flimelen for its own. Not a government, but the creation of many intent on preventing disaster or war.

Four men and one woman sat around a long table in the Great Hall. At the table’s head presided a stiff, unsmiling man of Middle Eastern extraction with a fringe of graying hair and a neatly trimmed mustache. He wore a scholar’s narrow spectacles, and indeed, he held degrees in law and diplomacy from universities in Cairo and New York. Though it was close to midnight, and the others had long since taken off their neckties and loosened their collars, he kept his jacket on, his necktie in the finest order. He viewed his position with the utmost gravity. For his efforts, he had been awarded the Nobel Peace Prize. Few people could boast that the fate of the world depended on him and not be branded an arrogant, bald-faced liar. He was one.

His name was Mohamed ElBaradei. He was the chairman of the International Atomic Energy Agency.

“This can’t be true,” said ElBaradei, running his finger across the report.

“I’m afraid there’s no doubting it,” said the man next to him, Yuri Kulikov, a poker-faced Russian who headed the IAEA’s Department of Nuclear Energy.

“But how?” ElBaradei searched the faces gathered at the table. “If this is so, we’ve failed in our every duty.”

“A program of institutionalized deception,” said Kulikov. “A shell game. For years, we’ve concentrated our inspection efforts in one spot, while they were secretly working in another.”

The men and woman seated beside him came from the top ranks of the secretariat, the professional staff that ran the IAEA. There was Oniguchi, a native of Japan, who headed Nuclear Science and Applications; Brandt, an Austrian and the sole woman in the room, who ran Technical Cooperation; Kulikov; and Pekkonen, the stolid Finn who headed up Safeguards and Verification, the IAEA’s most well-known department.

“There can be no question as to the data’s accuracy,” said Pekkonen. “The sensor was equipped with a next-generation chip capable of pinpointing gamma ray emission signatures with ten times the precision of the older model.”

ElBaradei was not a trained scientist, but twenty years’ work at the IAEA in Vienna had provided a grounding in the principles of nuclear physics. Emissions from radioactive materials like uranium or plutonium give off unique signatures. If accurately measured, those signatures indicate the age and enrichment of the radioactive material, and more importantly, as far as he and the individuals seated around the table were concerned, its intended use.

Uranium in its natural form could not be used to incite a nuclear reaction. It had to be enriched, or pumped up with a particular isotope-uranium-235. The most common means was to process uranium hexafluoride gas through a centrifuge, a rapidly spinning steel drum. Every time the gas was cycled, it became more enriched. To speed up the process, centrifuges were linked one to another so that the gas cascaded from one machine to the next. The path to success was straightforward: the more centrifuges you had, the quicker the uranium could be enriched.

For use in nuclear power plants, the radioactive mineral had to be enriched to thirty percent. For use as a fissile material-that is, to be capable of generating a nuclear reaction-it needed to achieve a level of ninety-three percent. The paper under ElBaradei’s eyes reported gamma ray signatures of an astounding ninety-six percent.

“The butterfly was over the target area for seven days,” Pekkonen went on. “In that time, it sent back thousands of atmospheric measurements. It’s unlikely that they’re all wrong.”

“But these readings are sky-high,” protested ElBaradei. “How could they have hidden it from us for so long?”