“What the hell was that?” Joe looked at the stylus, still vibrating free. A red line led off the paper. “The Dragon went off all by itself.”

“Don’t move!” Harvey began sketching on his clipboard.

Joe was close enough to Harvey to see him draw an outline of the room, the position of each man around the Dragon, equations, a curve of criticality. There was a foul greasiness to the air, a taste of melted paraffin.

Joe still wanted to finish what he was going to say, but the moment had gone. Imploded. Oppy knew it; the blue gaze said it. That was the color of Oppy’s eyes, Joe thought: ion-blue.

“You set me up.”

“I asked you to tell the truth and you did,” Oppy answered.

“I’m not done.”

“Yes, you are.”

Harvey stared up from his scribbling. “You did it!” he told Joe.

“Me?”

“The core was already near the margin of criticality. The human body is composed mostly of water—hydrogen dioxide—which reflects the neutrons. Oppy and I didn’t matter. You’re bigger. When you leaned over the Dragon, you triggered the counters.”

“You’re a more unpredictable factor than I’d thought,” Oppy said.

“It doesn’t matter,” Harvey said, “we got the data.”

“Well, are we radioactive now?” Joe asked.

“We’re fine,” Harvey said. “Nothing really happened.”

“Nothing really happened,” Oppy agreed.

They looked at Joe with twin scientific detachment, a sudden, palpable line between them and him. He stared back, for the first time his mind fully engaged. It was obvious that Oppy had won. What was interesting was Harvey’s surrender, his relief about it.

“You know,” Harvey said and turned to Oppy, “it occurs to me that the bomb would probably be flown to Japan. What if the plane crashed? Maybe I should run the Dragon in salt water.”

Even his Southwestern tonalities seemed to change subtly, to ape unconsciously Oppy’s Eastern croak. His stance shifted, his enthusiasm grew.

The effort of winning Harvey back had taken a toll on Oppy. Each crisis appeared to take an ounce of flesh, and now he looked cadaverous and more determined than ever. He nodded proudly, encouraging the flow of ideas that was purely Harvey, until Harvey asked, “You really wanted me to count down Trinity?”

“I wanted an American physicist to do it,” Oppy answered, “and my first thought was you. An American voice.”

“Listen.” Joe broke the mood.

Oppy snapped, “What?”

“Just listen.”

Omega was hidden in tall pines, amid the calls of jays and canyon wrens, the wind tugging at treetops. It took a moment to hear the siren.

“Fire,” Harvey said.

They counted the blasts together. Oppy wore an ironic smile, as if disaster were only to be expected.

“Tech Area,” said Joe.