Abruptly the mike went dead, just as Illya said, "If he reaches the shore, I'll lose him. Can't take that chance."

"I'm going after him," Illya said again, to the silent mike. If Waverly had different ideas it was too late now.

He increased the speed on the U.N.C.L.E. helicopter, passing over the running man, and then turned and took it down, cutting off Dr. Sagine's fight to the opposite shore. He landed, switching off the rotors.

Dr. Sagine veered to the right, running out toward the middle of the lake. Illya dug his U.N.C.L.E. special from his belt and leaped out, running. He chased headlong after the fleeing Dr. Sagine, across the gleaming, bleached-bone whiteness of the crystallized lake.

ACT VII: LAST COMMAND

Napoleon Solo was sitting in the co-pilot s chair of the U.N.C.L.E. jet that had picked him up in Granite River. Eyes closed, he was fighting a losing battle against exhaustion, when Waverly's frantic call came over the radio.

The jet had wound its way down from the Rockies, following the irregular, twisting course of the Colorado River. Their only sighting in the time they had been aloft had been another U.N.C.L.E. search plane. There had, of course, been no sign of Dr. Sagine.

The radio crackled. "Attention, all Squadron B- units. Attention, all Squadron B units. Report your positions immediately. Repeat. Report your positions immediately. Urgent. Red Line urgent."

The sound of Waverly's voice jarred Solo into sudden wakefulness. He sat erect, shaking his head. The pilot, a gaunt, slackjawed Scot named McDuffee, reached for the microphone.

"Control, this is B Leader One reporting. Heading south-southwest, search course above the Colorado River. We have just passed over Grand Canyon, approaching the Nevada border. Over."

There was no instant response. Solo, listening attentively, heard the other U.N.C.L.E. jets relaying their positions. After a moment, Waverly's voice boomed again. "B Leader One, this is Control. Alter your course point-zero-six degrees, due west, full maximum speed. Place all emergency rescue equipment on stand-by readiness. Your destination is Lake Mead. Acknowledge, please."

"Roger, Control," McDuffee said. "What's the exact position?"

Waverly told him what it was. "How long will it take you?"

McDuffee checked his instruments quickly. "Ten minutes, sir," he said. "We're on our way."

Solo grabbed the microphone. "Mr. Waverly," he said. "This is Solo in B Leader One. What's going on at Lake Mead?"

There was a brief pause. Then Waverly said, "Mr. Solo, I thought you were still convalescing. But I am glad you are along. We may need your assistance."

"Lake Mead is formed by Hoover Dam," Solo said. "That's where you sent Illya this morning. What's happening there?"

Waverly said: "I have been trying to raise Mr. Kuryakin on his communicator, but there is no response."

"You think he's hurt, then?"

"Possibly," Waverly said "Though I think not. I don't want him to land on Lake Mead, but I can't reach him."

"Why the rescue equipment?" Solo asked. "And why the urgency?"

"Simply because," Waverly said, his voice tinged with impatience, "if Mr. Kuryakin does not get off the surface of Lake Mead within the next few minutes, he is going to be trapped on a rushing torrent of fresh water instead of solid rock salt."

Solo got it then, touching his mind like an electric shock.

"Good Lord!" he said slowly. "The antidote!"

"Precisely," Waverly said. "It was introduced into the Colorado some time ago at the THRUSH site in Pardee. I have had planes watching its progress. Even in controlled amounts, it decrystallizes the water at a fantastic rate of speed. Most of the Colorado has already been returned to its original state. When the water carrying the antidote reaches Lake Mead..." He paused. "I am sure I needn't explain further."

"No," Solo said. "How much time have we got?"

"Approximately fifteen minutes, maximum, according to the present rate of change. We have to make contact with Mr. Kuryakin before he gets too far away from his helicopter."

"And if we can't?"

"Then I am afraid his fate will be in your hands."

"But it's going to take ten minutes to reach Lake Mead," Solo said. "That only leaves us five minutes to launch a rescue operation. That's not much time."

"I am well aware of the time factor," Waverly said. "We can only hope that Mr. Kuryakin can be raised on his communicator before that necessity arises. Keep your own communicator open to Channel D. If he answers too late to escape by helicopter, then you will have to take over with rescue instructions."

"Yes, sir," he said. "Solo out."

He replaced the microphone, rising. As he did, he saw they had lost altitude. Through the windshield, he could see the Colorado River below, no longer white, now cold and surging through the rock canyons toward Hoover Dam and Lake Mead. He wet his lips, turning to McDuffee.

The U.N.C.L.E. pilot was barking orders to his crew on the jet's communication system. He had set the throttle wide open.

When McDuffee finished, Solo said, "I'm going to supervise the operation if it's needed. See if you can set a new speed record, will you, Mac?"

"As good as done," McDuffee said, but his mouth was tight.

Solo left the cockpit and hurried through the plane to the tail section. He took his communicator from his pocket as he went, thumbing out the antenna. He reported to Waverly on Channel D that he was waiting on stand-by.

Illya Kuryakin still had not acknowledged.

Solo reached the tail section. The crewmen there were already setting up the newly-developed U.N.C.L.E.. aeronautical rescue devices carried in that section. He stood watching them, feeling a tightness in his chest as he listened to the silence from the communicator in his hand.

TWO

Ahead of Illya as he ran, the THRUSH scientist was following a straight course toward the rock-covered shore to the right. Illya Kuryakin had narrowed the distance between them to a hundred feet, and was gaining rapidly. He was younger, more agile, than Dr. Sagine, and he knew that it would only be a matter of seconds before he overtook him.

And that made him careless. He forgot about the gun Dr. Sagine was carrying. In his pursuing dash across the shining salt floor of the lake, Illya's mind was focused on only a single objective, and that was catching the man in front of him before he reached the cover of the shore. He had pushed the existence of the gun completely from his mind.

When Dr. Sagine suddenly halted his flight, turning abruptly, Illya did not immediately understand why he had done so. He slowed himself, a natural reaction, and then he saw the THRUSH scientist's arm stretch out in front of him, and the transitory view of metal, and he knew, almost too late, what the reason was.

He flung himself to the side, his left shoulder connecting solidly with the grainy, unyielding surface, jarring him. The bark of the gun in Dr. Sagine's hand split the morning stillness, and a bullet furrowed salt near Illya's face, spewing brackish chips at his eyes. He rolled twice and came up on to his knees, trying to see where his assailant was, his special held up in his hand. The gun roared again, directly in front of him.

Sagine's second shot took Illya high in the left side of the chest. The force of the impact stunned him, driving him over onto his back. His chest went numb. He lay there, looking up into the pale yellow ball of the sun, and he thought dazedly, He shot me. I'm hurt bad.