He heard the inner hum of motors from the earth beneath him. Stacking chair upon table, he pressed his ear to the air conditioning duct grate, but the sounds through the building were like vague, confused whispers always subordinated to the throb of the unexplained engines.

He jumped down from the chair, replaced it as it had been. It occurred to him that listening devices were one of the easiest gimmicks to assemble. He strode to his table of sorted parts. Using the small aluminum cones, he fashioned larger ones from all available aluminum which he then formed into a telescopic rod. With an amplifier from the dismantled sender-listening set, and the reassembled earplugs, he had himself a directional sound pickup.

Returning to the duct-grate, he aimed the cones, inserted the earplug which was connected to the sound amplifier.

He smiled in cold pleasure. While the sounds he was able to pick up through the elaborate air conditioning system were faint, he could by moving the cones locate the direction of each different sound.

He examined the duct-grate closely, but finally had to give up the idea of getting out that way. The grate was very solidly welded into the wall—a first-class piece of modern workmanship.

But that thought gave him a different idea. The air conditioning had been added to Broadmoor Rest comparatively recently, but the building itself was an old one, probably dating back to the last century. A staid, respectable site for a Thrush retreat but perhaps with a few chinks in the armor.

Solo strode to the fireplace in the corner, knelt and looked again at the heavy metal plate which blocked off the chimney. He smiled slightly. It was as he’d hoped: the chimney itself was constructed of brick, so it had been impossible to secure the plate any more firmly than by the use of bolts. And bolts, unlike welding, could be removed comparatively easily.

It took him less than half an hour to get the metal plate out of the way. By the time he finished he was covered with soot that had probably been there for fifty years or more—since whenever the old mansion had been turned into an exclusive private sanitarium, and this room into isolation quarters. Looking into the chimney, he found that it led both downward and upward. Apparently the level he was on wasn’t yet the lowest one at Broadmoor; he’d suspected that, from his use of the directional sound pickup at the air conditioning grate. There had been the muffled sound of engines somewhere below…

He took one last look around the room, at Illya and Barbry, both asleep. Then he shoved the sound-directional detector into the chimney ahead of him and worked his way into it.

Bracing feet and shoulders against the rough walls of the chimney, he inched his way downward into darkness. Loosened soot and dirt cascaded around him; he had to move doubly carefully to avoid stirring so much of it that he’d be unable to breathe. Twice he gulped in lungsful of mostly soot, and barely managed to keep from breaking out into coughing fits. Then the soot would sink into the darkness beneath him and he would breathe in tortured gasps of comparatively clean air.

The passage was apparently the main chimney for this part of the building; Solo passed several branches which apparently led to other sealed-off fireplaces. At one point light entered the shaft, and as Solo reached that place he saw another branch leading to another fireplace, this one not sealed off. No sound came from the room; apparently it was unused. From what he could see from the passageway it seemed to be just a storeroom. He went on, still downward toward the machine sounds, which were growing steadily louder.

At last he reached the bottom. The sounds had by now become a deep drumming which filled the shaft with almost physical waves of sound. There was light here, bright light—another unsealed opening. Solo approached it cautiously, as silently as possible even though he knew any sound he made would almost certainly be lost amid the engine noise below.

Then his feet touched a bed of soft ashes, and he sank into them nearly up to his knees. There was a semi-brittle crust to the ash pile, as though it had lain undisturbed for scores of years. Except for where his feet sank into them, the ashes remained undisturbed.

It was a large burning area, Solo saw—apparently it had been used originally as the main incinerator for the building. Now, with the ashes settled to a depth of only a few feet, the unused incinerator formed a small, shadowed room with an opening about three feet square through which brilliant white light lanced sharply. Solo paused, then knelt slowly, letting his eyes grow accustomed to the light before he risked a look outside.

When he did, he stared out into a hangar-sized area, blindingly white with lights. He couldn’t even guess how far below ground this massive room was, but he knew it must be deep inside the mountain. Electronic controls, computers, switches and testing equipment were banked along the white walls. He moved his gaze slowly until he had passed over the radiation-suited figures to the heart of the immense plant—the place where the separately gathered components had now been assembled into a small but obviously functional atomic device.

He stared at the assembled device, his eyes wide.

As he watched, an abrupt whistle blew through the huge arena scooped from the earth. The white-suited, helmeted engineers and scientists at work in the chamber where the atomic device had been assembled stopped working and lined up to exit the glass enclosed room within the larger plant.

Solo held his breath as the first man stepped through the double set of exit doors. Outside the chamber, they pulled off their helmets.

The impact was like a sharp karate blow in the face to Solo. One’s mind could reel under the incredulous truth being revealed to him.

Abruptly, he remembered why the name of Broadmoor Rest had seemed so familiar to him from U.N.C.L.E. briefings. Again and again over the past two years, reports had come in from parts of the United States, Russia, France, Germany, records of scientists, engineers, physicists—all in sensitive missile work, each suffering mental breakdown, going to one sanitarium or another, but all, he now realized, eventually ending up here at Broadmoor Rest. Though the briefings had mentioned this place often enough to impress its title on his mind, there had been no concentrated reading of the names and professions of the men arriving here in an almost constant stream in the past twenty-four months.

He shook his head. Though often repeated, the idea of mentally ill men and their arrival at Broadmoor had not been noted in any context that would give it meaning—not until now. Those men had certainly been subjected to unnatural pressures, tensions and strains. Many of them crumpled under it, and it didn’t add up to anything except the increased tempo of life in the atomic age. Men’s minds and nerves snapped; they needed hospitalization and treatment—Broadmoor Rest had been internationally respected as one of the best. These men had earned the best possible care; who would suspect they came here not because they were ill at all, but because they had sold out their governments, their families, their careers for the quick fortunes dangled before them by Thrush?

Because here they were.

Every face revealed to Solo by the removal of a helmet was familiar to him from the photos in the U.N.C.L.E. briefings. Every reputation was known to him, along with the facts of mental or nervous breakdown. Wolgang von Shisnagg, from the western zone of Germany, Kurt Helmeric, Pierre Curie de David—the whole long list of the brilliant engineers, scientists.

He slumped there for a long time, hidden in the darkness of the abandoned incinerator shaft, watching the Who’s Who of missile scientists pass by him. It took some moments for him to recover, he who had few illusions left concerning every man and his price.