AVOICE FROM VERY FAR AWAY SAID, "He's fighting it."

"Is he?"

"Yes. Look."

And then, a moment later, Hall coughed as something was pulled from his throat, and he coughed again, gasped for air, and opened his eyes.

A concerned female face looked down at him. "You okay? It wears off quickly."

Hall tried to answer her but could not. He lay very still on his back, and felt himself breathe. It was a little stiff at first, but soon became much easier, his ribs going in and out without effort. He turned his head and said, "How long?"

"About forty seconds," the girl said, "as nearly as we can figure. Forty seconds without breathing. You were a little blue when we found you, but we got you intubated right away and onto a respirator."

"When was that?"

"Twelve, fifteen minutes ago. Ligamine is short-acting, but even so, we were worried about you… How are you feeling?"

"Okay."

He looked around the room. He was in the infirmary on Level IV. On the far wall was a television monitor, which showed Stone's face.

"Hello," Hall said.

Stone grinned. "Congratulations."

"I take it the bomb didn't?"

"The bomb didn't," Stone said.

"That's good," Hall said, and closed his eyes. He slept for more than an hour, and when he awoke the television screen was blank. A nurse told him that Dr. Stone was talking to Vandenburg.

"What's happening?"

"According to predictions, the organism is over Los Angeles now."

"And?"

The nurse shrugged. "Nothing. It seems to have no effect at all."

"None whatsoever," Stone said, much later. "It has apparently mutated to a benign form. We're still waiting for a bizarre report of death or disease, but it's been six hours now, and it gets less likely with every minute. We suspect that ultimately it will migrate back out of the atmosphere, since there's too much oxygen down here. But of course if the bomb had gone off in Wildfire…"

Hall said, "How much time was left?"

"When you turned the key? About thirty-four seconds."

Hall smiled. "Plenty of time. Hardly even exciting."

"Perhaps from where you were," Stone said. "But down on Level V, it was very exciting indeed. I neglected to tell you that in order to improve the subterranean detonation characteristics of the atomic device, all air is evacuated from Level V, beginning thirty seconds before explosion."

"Oh," Hall said.

"But things are now under control," Stone said. "We have the organism, and can continue to study it. We've already begun to characterize a variety of mutant forms. It's a rather astonishing organism in its versatility. " He smiled. "I think we can be fairly confident that the organism will move into the upper atmosphere without causing further difficulty on the surface, so there's no problem there. And as for us down here, we understand what's happening now, in terms of the mutations. That's the important thing. That we understand."

"Understand," Hall repeated.

"Yes," Stone said. "We have to understand."