"He has a point, sir," said Illya. "Not only was the firing area under constant observation throughout the time, but we were there with the first investigating party no more than three minutes later, and he was still warm. Though under the circumstances..." He paused, and thought better of continuing.

"That was the subject of some conjecture on my part," said Waverly, "and I have reserved judgment during the search for evidence. The identification pairs are perfect—much of his face had been sloughed but his eyes were undamaged, as were the fingerprints of his left hand. And the identification is more than positive; it is perfect."

"How much of the Bertillion was checked?"

"Nearly everything but the face and ears. It didn't check out one hundred percent, but ninety-four is passing when the measurements are four years old."

"Uh-huh." Napoleon nodded. "I think I'd like to take a look at that test again. We made a film off the videotape, didn't we?"

Waverly looked at Illya, who shook his head. "Frankly, sir, I haven't the least idea. The project was dropped after the accident, so there was no reason to save much pertaining to it. King never kept more than the most skeletal notes on paper and carried all the essentials in his head. When that got scrambled, there was no way of going into what he might have done wrong."

"It might still be worth checking. Since we computerized Section Four they save everything but string. I'll put a tracer on it and see what they find."

He took the gray handset from under the edge of the table and tapped a code number on the keys, then spoke in a clear, precise tone, spacing his words carefully. "Search—Particle, Accelerator, Rifle—cross-index King, Joseph. January, 1965." He raised his glance to Napoleon and Illya, shielded the mouthpiece and explained, "Records Retention is experimenting with a voice-programmed retrieval system. Sometimes it works."

He dropped his eyes and raised his voice. "Film," he said, and looked up again. "There is only one entry."

"We'll have to go in there," murmured Solo, and shrugged at Illya's puzzled glance while Waverly addressed the voice-programmed retrieval system as he would a retarded child. "Film. Of final test on P, A, R." He listened a moment and nodded. "Very good. Delivery."

A few seconds later he said, "Waverly here. Your automated filing cabinet has a film clip which I would like sent to my office. Thank you."

He replaced the handset and said, "Something which may or may not fit any of the categories I requested is on its way up. A possibility has just come to mind..."

"A theory?"

"It is a capital mistake to theorize with insufficient data," Waverly quoted. "The evidence pending should, however, prove sufficient."

"And if it proves he could not have gotten out alive?"

Waverly cleared his throat and reached for his pipe. "In that case, Mr. Kuryakin, we reserve judgment. King was—or is—a remarkably clever man, and I do not flatter myself there is no possible trick I could fail to see through."

An alarm bell shattered the momentary silence of the office, and the three looked at each other with wild surmise until Napoleon said, "It's an alarm bell."

By that time Waverly had switched the television monitor to the corridor where the signal had originated. An agent was doubled over in the middle of the hall, near a manual alarm box; as they watched he fell to the floor and tried to crawl towards an open door.

"He's been poisoned," Illya said.

Before the last word left his lips three more alarms sounded, followed in moments by a clamor of others. The telescreen flashed from one hall to another, to women and men stumbling dizzily, clutching at doorhandles, staggering and falling, gasping with pain.

"It's in the air!"

Neck muscles tensed and diaphragms contracted even as their minds realized the symptoms would have already manifested themselves and ordered breathing resumed—though carefully at first.

"No it's not," said Napoleon. "Look. Nobody in the offices is affected." And indeed figures were visible standing just inside open doorways, though some held their heads and leaned heavily or sat down.

"Nobody?" said Illya. "I don't know about you, but my head suddenly feels stuffed up—and I had my annual cold in March."

Napoleon registered sudden concern. "It's my stomach," he said, matter-of-factly. "No, my chest. But it's not getting any worse."

"It may," said Illya. "At any moment."

Chapter 2: "My Teeth Itch."

Napoleon was already on his feet and heading for the door. It zipped open before him, but he paused before venturing past the portal. Then, with Illya just behind him, he stepped cautiously into the deserted hall, filled with the clangor of the alarms. Waverly was at his desk, communication circuits abuzz with questions and generally negative answers.

"It's not radiation anywhere in the electromagnetic spectrum as far as we can tell," was one hedging answer. "At least nothing we can detect."

"The air is still testing pure," came another answer, "at least as pure as it ever does considering where we get it."

"Even if there was somebody invisible running up and down the halls knocking people out, we'd detect him by mass, by body heat, by smell..." said a disconcerted security officer. "There's nobody there—I guarantee that personally!"

As Napoleon stuck his neck out a wave of nausea swept over him. He clenched his teeth, fixed his eyes on a closed door twenty feet away, and put as much effort as he could summon into a dash for it. The panel zipped open a fraction of a second slow and his right shoulder banged painfully into it as he reeled into the conference room and collapsed into a chair, gasping. Illya followed a second later, twisting his body sideways to miss the returning door and letting it close behind him.

"The headache's worse," said Napoleon, catching his breath.

"My teeth itch," said Illya critically. "It's not a gas, it's not radiation...wait a minute. It's not electromagnetic radiation, but look!" He pointed at the inner side of the metal door panel, where cracks were beginning to appear in the painted surface. As they stared, a piece of paint about the size and shape of a postage stamp broke free and fluttered to the floor. Other areas showed signs of letting go their bond to the metal and joining it.

"It's not an earthquake," said Napoleon doubtfully, "but it has many of the same symptoms. What do you think of infrasonics?"

"Personally I dislike them. Intellectually, there's something in what you say. It's not like that thirteen-cycle 'fear' tone you ran across in Rumania, though."

"No, this one is almost audible. I'll bet it's tuned to the width of the corridors here!—they're all the same width and mostly bare-walled. They'd make perfect whaddyacallem."

"Resonant cavities," said Illya. "That would also create a standing wave in the halls." He looked around the room distractedly. "Let's see if there is one."

His eye lit on an ashtray, heaped with the fallout of the morning's briefing. Unsteadily he stood up, gripped the dish, and wobbled towards the door, which obediently zipped open before him and stuck halfway. Illya braced himself against the doorframe and pitched the handful of gray powder into the empty hallway. The stuff separated into a cloud of smoke and began to settle out towards the floor. As it settled it drew into two vertical bands of light and gray, dividing the hall into ghostly thirds.