"There's got to be something else."

"Think of it this way. What we're building here is a secret weapon, right? You're my secret weapon. Your other choice is the stockade, if you want to go back there."

"You're a lunatic, Captain."

"What can you do about it?"

Heart shot? At this range, a round would punch out the captain's heart, aorta, half a lung. Joe let the gun hang straight down. Fired. The elk's legs jerked once, like a spasm in a dream. It stretched its neck across his feet. Its eye faded and died.

"I'll expect a report later on anything Oppenheimer says, conversations with Groves especially, anything political in particular." Augustino hadn't flinched. He took the deep, satisfied breath of a man turning home. "The usual."

5

The car was a blue Buick sedan with a V8 engine and gray plush interior. In the back were Brigadier General Leslie Groves and Oppy; in front, Klaus Fuchs, a field radio, and, at the wheel, Joe. The inside of the windows beaded with sweat. Outside, all of New Mexico seemed to tip from Los Alamos, mesa turning to foothills of black nut pines, pinons, on white snow.

The general's whole body looked tucked, badly, into his uniform. Groves was a tall man, his gray hair was vigorous and wavy, his moustache bristled and his eyes were bright as steel, but below the collar, starched khaki and overcoat bulged everywhere under the pressure of soft fat. General Groves was fond of Los Alamos. His domain extended from the giant production plants of Hanford, Washington, and Oak Ridge, Tennessee, to the original labs in Chicago, but they were run by Union Carbide and DuPont or the pain-in-the-ass Europeans in Chicago, whereas Los Alamos was his personal duchy and run by his inspired choice, Oppenheimer, and was the real heart and soul of the project, the greatest scientific effort in the history of mankind. The Buick, the best car in the motor pool, was always set aside for him when he came and he was always driven by Joe. Other brass and VIPs who had come from Washington with the general referred to Joe as "Groves' Indian". The story got around that even the President had asked Groves about his "Indian companion".

Oppy wore an old Army greatcoat that could have been wrapped round him twice and a pork pie hat that emphasized the narrowness of his skull. His hands fidgeted because the general allowed no smoking in the car. Klaus Fuchs sat practically at attention in an overcoat and fedora, rimless glasses that seemed to flatten his eyes.

Groves hadn't wanted anyone from the British Mission, they thought Los Alamos was Oxford, but as Oppy said when he picked up the general, Fuchs wasn't really British.

"I'm going to see the President tomorrow," Groves said. "He's going to ask me why we need a test. We have barely enough uranium for a single bomb, and hardly any plutonium at the moment. Why should we waste any of it on a test, he'll ask."

"There are two separate devices," Oppy said slowly and patiently, not because Groves was stupid but because the general was not naturally articulate and these were the simple words Oppy wanted passed to Roosevelt. "There is the uranium device, which has basically a gun-barrel design. We don't expect to have enough refined uranium until July and a little thereafter, but we're confident the device will work. Then there is the plutonium device, which has a complicated 'implosion' design. By July, we expect to have enough plutonium for two bombs, and by August enough plutonium for two more bombs, and by September plutonium for two more, but we have no certainty the design will work. It's the plutonium device we have to test, and it's the armoury of plutonium devices that will end the war, not the single detonation of our uranium device. You can tell the President that choosing a test site is a sign of confidence."

"We're depending heavily on this site being right," the general said. "The alternative test sites are some islands off California, sand bars off Texas, some dunes in Colorado. The last place I want to hide an atomic blast in is California."

"That depends on how big it is, of course," Oppy said.

"Well, how big will it be?" Groves demanded,

"Five hundred tons of TNT is the current estimate of the yield," Fuchs answered. He was part of the Theoretical Group estimating the blast.

"Couldn't it be much larger?"

"Theoretically, it could be five thousand tons, fifty thousand tons. Almost no limit."

"Five hundred is a start." Groves was mollified. "I'm going to tell the President we're going to set it off on the Fourth of July."

"Wonderful," Oppy said.

Too bad we missed Christmas, Joe thought. Maybe this was the time to tell the general that the head of security on the Hill was of the considered opinion that Joe Stalin's special agent was Robert Oppenheimer and they ought to pull off the road and get the whole thing sorted out. Even if there was nobody capable of taking Oppy's place and even if test, bomb and ultimate victory had to be scuttled.

Maybe this wasn't the time. Perhaps this was the best time to be a dumb sergeant, the "Indian companion".

As soon as they hit the highway at Esperanza, Joe put his foot down. The wartime speed limit was 35 mph, but the general always preferred to cruise at 85. Petrol rationing had largely emptied the roads and the prow of the Buick could roll on two-lane tarmac, sometimes narrowing to one lane, with wide shoulders for slow-moving donkey trains, carts, wagons.

Santa Fe passed as an electric glow under an ash-coloured sky. An Army hospital was pumping money into the town. Signs offered drinks, boots, curios.

As Oppy and Groves droned on about problems of the isolation of isotopes and allotropic states of plutonium, Joe wondered why he had gone to bed with Mrs Augustino. Was it her he wanted? Some other woman? Any woman?

Like a conscience a state trooper's motorcycle emerged, siren wailing, from behind a sign that said, "War Bonds Are Bullets!"

The general's travels were secret; it was understood he didn't want to talk to any local justice of the peace. Joe floored the accelerator. New Mexican troopers had black uniforms and black bikes. At 100 mph, the dark silhouette became a dot in the rear view mirror. Swaying on passenger straps, Groves and Oppy went on talking about construction schedules. Fuchs spoke only when asked, otherwise he was as quiet as a drawer. Information on hand but only when demanded.

In the fields, the breeze rattled rows of chili, unpicked because a farmer could walk into Boeing's Albuquerque office and keep on straight to Seattle to build B-29s and draw more money in a month than he'd ever seen in a year.

"Explode. Implode. Two apparently contradictory events at the same moment," Oppy was saying. "I wouldn't suggest trying to explain it to the President. Still, it is a sweet concept."

Past Albuquerque and through the lower valley, crossing the Rio so often it seemed a dozen rivers, Oppy and Groves discussed problems ranging from plutonium assembly to sugar for the commissary. The car pressed against a headwind towards gray clouds that built and receded at the same time. At Antonio, a farming town of dimly lit windows, they left the highway for an eastbound single lane of frayed tarmac, crossed the Rio one last time and entered a vast, tilted basin of scrub and low cactus. There, the clouds moved forward and snow began to fall, lightly to begin with, tracing the wind, more heavily as the sun was covered, packing on the wipers and coating the headlights.

"If Hitler had the bomb…" Groves said. "We get reports that this winter offensive of the Germans is just to stall while he finishes some secret weapon. Suddenly he has jet-propelled planes, new rockets."

"If Hitler has the device, he'll use it on the Russians," Oppy said.