Leaving some of the agents to guard the prisoners they had taken, Solo led the remainder to the elevators against the left-hand wall. One of the technicians went to the control board behind the partition to the right, found the levers operating the elevators there and brought them all to basement level.

A group of agents rode to each of the three remaining levels of the fortress for search-and-seizure operations. Solo went to the top floor, the laboratory and manufacturing plant.

A state of confusion reigned there. The scientists, workers and guards there were well aware of the U.N.C.L.E. invasion, and were attempting to organize themselves when Solo and the U.N.C.L.E. agents with him emerged from the elevators.

Solo shot one guard, brandishing a machine gun, in the leg, and one of the other operatives winged a white-coated man with a revolver. After that there was no resistance.

Solo, after the THRUSH men had been herded into one section of the laboratory, went immediately to the private lab of Dr. Sagine at the far end. He found it deserted.

"Where is Sagine?" Solo demanded.

The THRUSH men were stony-faced.

Solo singled out a hawk-faced little man with frightened eyes, grabbed him by the scruff of his white-smock and dragged him of to one side.

"Better talk, friend," Solo said. "You will eventually, you know. We have ways..."

It did not take much persuasion on Solo's part to learn that Sagine had left the fortress some time late the previous day, bound for the town of Pardee, in Utah, to supervise the introduction of the salt chemical into the Colorado River. Solo then questioned the man carefully, asking which of the scientists present knew of the formula for the chemical, and of its antidote, and how the antidote was administered. The frightened little man relinquished the answers almost gratefully.

Solo then checked with the balance of the U.N.C.L.E. force on the lower floors. He was told by the leader of each group that everything as under control, that prisoners had been taken.

U.N.C.L.E. now controlled the fortress fully.

One of the U.N.C.L.E. agents in the warehouse also informed Solo that a search had revealed hundreds of jars of chemical there, ready for transportation. The agent had questioned one of the captured guards and had learned that THRUSH had not as yet transferred any out of the fortress. They were waiting to receive word as to the success of the Colorado River venture. As soon as that word had been given, the chemical was to be shipped by helicopter to a hidden THRUSH Air Base near by for distribution throughout the world.

Solo immediately used his communicator to contact Mr. Waverly, waiting in New York, and told him that the assault had been a success. He relayed what the little man had told him about Dr. Sagine, and that his earlier conclusions concerning THRUSH knowledge of the salt chemical and its antidote had been accurate...one of the captured scientists knew the formulas and how they were used and regulated.

"Good," Waverly said, "Mr. Solo, our agents from Salt Lake City have conducted a successful raid on a THRUSH camp in Pardee, Utah. They have confiscated several jars of the salt chemical and what, according to one of the scientists they had captured there, was the antidote. There was no sign of Dr. Sagine, the agents report. If the THRUSH personnel in Pardee knew where he was they weren't talking."

"How about the antidote," Solo queried.

"None of the scientists in the Pardee group professed to know how the antidote was regulated," Waverly said. "Our agents are awaiting instructions."

As Waverly remained on stand-by, Solo questioned the man who had been designated as having knowledge of Dr. Sagine's chemical. The THRUSH man at first refused to tell Solo anything. But when one of the U.N.C.L.E. agents found what appeared to be the formula for the chemical processes in Dr. Sagine's private lab, and when Solo told the man that if they were too late to prevent floods, because of the time it would take for U.N.C.L.E. chemists to learn the proper usage, then the man could be held directly responsible for whatever carnage was wreaked. The THRUSH scientist finally acquiesced, telling Solo everything he knew.

Solo hurriedly relayed the information to Mr. Waverly, just as the scientist had told it to him. Waverly listened carefully, making sure that he had the exact dosage of the antidote to be placed in the water to prevent flooding, and then had Solo wait while he spoke with the agents in Pardee. The antidote would be administered immediately, in the proper amounts, by an U.N.C.L.E. chemist that Waverly had sent to Pardee in anticipation of that very reason the night before.

When Waverly came back on Channel D, Solo said, "What about Dr. Sagine, sir?"

"We don't know where he is at present," Waverly said, "though I have my suspicions. I expect he is checking on the results his chemical has had on the Colorado River. By helicopter, I should think, since that appears to be the method of transportation THRUSH used to reach the camp at Pardee."

"Then he could be anywhere along the Colorado," Napoleon Solo said.

"Yes," Waverly said. "As I told you last night, I have sent Mr. Kuryakin to Hoover Dam. Sagine would logically wish to inspect that most important site. But if he had not gone there, then we have U.N.C.L.E. jets in the air over the entire area along the Colorado north from the Dam. We shall have Dr. Sagine before too long."

Solo allowed himself a small, tired smile.

"It's almost over," he said. "There were times when I wasn't so sure of the outcome."

"Quite so, Mr. Solo," Waverly said laconically. "Quite so."

Solo said, "What do you want me to do now, sir?"

"From the sound of your voice," Waverly said, "I think a hospital bed is in order."

"I'm fine," Solo said wearily.

"Hmm," Waverly said. It was a skeptical sound.

"I'd like to join in the search for Dr. Sagine," Solo said. "There's a small airstrip outside Granite River where one of the jets could land and pick me up."

Waverly seemed to be pondering the request. He said finally, "Very well, Mr. Solo. If you are quite sure you are all right."

"Yes, sir," Solo said. "I'm sure."

He wasn't really sure at all.

FOUR

Illya Kuryakin, piloting the quicker, more durable U.N.C.L.E. helicopter, had drawn to within five hundred feet of the fleeing THRUSH craft when they began firing on him.

Twin bursts of flame erupted from tail guns mounted beneath the cockpit. Illya, reacting instantly, pushed hard left on the throttle, banking. He saw a long white scratch appear in the glass dome above him as one of the bullets slashed past, and felt a rocking jar as another thunked into the landing gear.

He manipulated the throttle, dipping, cutting the speed momentarily, and then opening up again. The tail guns on the THRUSH helicopter spit more flame, but the hail of bullets passed harmlessly above him.

The U.N.C.L.E. helicopter was likewise equipped with artillery, and Illya wrapped his hand around the firing mechanism, thumb touching the button. But he didn't fire. He could see that there were two men in the machine he was pursuing, the pilot and a squat figure seated beside him. He could not identify the second figure from this distance, but he caught fleeting glimpses of a yellowish mane of hair through the glass dome.

From the picture of Dr. Mordecai Sagine that he had seen on the visi-screen in Waverly's office the day before, he had an idea that the perpetrator of the salt chemical was that second man If this were the case, he knew that U.N.C.L.E. would prefer to have Dr. Sagine alive than dead.