After penetrating about an inch, the quiet hum of the drill changed to a shrill whine, then jammed. Napoleon withdrew the drill and looked at the battered tip.

"Very solidly built," he said. "At a guess, I'd say the walls are quarter-inch steel plate, covered on both sides with native lumber to give the appearance of a rickety shed. And since not even Thrush would go to all that expense and trouble for an isolated warehouse, this place is important. Now, if we can just find the proper key..."

Illya was eying a knothole in a board near the top of one of the windows. Suddenly he reached up, inserted his thumb in the hole, and pushed. With a quiet whir of machinery, a steel shutter slid into place across the window opening.

"That's it, then," he announced. "The knotholes are concealed pushbutton controls. I noticed there was one near each window. I think there are a few others."

They found a total of six, scattered at random points throughout the building. "Now, if we just knew what each of them controlled," Illya mused.

"Only one way to find out," said Napoleon, reaching out to press the nearest one.

There was the same quiet hum of well-oiled machinery, and a twenty-foot section of the floor began to descend into the earth.

"Jackpot!" said Napoleon, leaping onto the descending elevator with Illya close behind.

With his U.N.C.L.E. Special in his hand, Napoleon waited as the elevator slowly descended. Illya took out his communicator and brought Kerry and Lee up to date.

When the elevator finally stopped, Napoleon estimated that they had dropped at least two hundred feet. They stepped off into a well-lighted underground passage that traveled only a few yards and then opened into a huge cavern. The cavern was apparently empty of dirigibles, but several pieces of machinery stood about and a huge pile of empty packing crates were pushed against the wall a few feet from them. A small stream trickled across the cavern floor.

Illya had put away his communicator and was drawing his gun. "But how do they get the dirigible out of here?" he asked. "It wouldn't fit in that elevator."

Napoleon stooped and began examining the rocks at their feet. After a few seconds, he straightened and nodded with satisfaction. "This isn't a natural cave," he said.

Illya looked around. "It will do until one comes along."

"No, this is a ravine. Thrush has built a roof over it and apparently covered the roof with dirt and planted grass and trees on it."

"Amazing," Illya murmured; "I never realized Hunding was a Thrush."

"Richard Wagner, Die Walkuüre, and it was a tree inside his house, not on the roof." Napoleon tossed off the identification and returned to speculating on the hanger construction.

"They must have blocked up this end with real ricks and dirt, brace by a steel wall. I wonder how they managed the other end, though. They must have something pretty elaborate in order to get the dirigible in and out."

"Right you are, sonny," came a cracked voice from behind them. "Just drop those guns and I might tell you about it."

The two agents dropped their pistols and turned slowly to face the speaker.

The man was wrinkled with age, but still ramrod-straight, with fierce eyes and a grin revealing broken teeth. Held firmly in the old hands was a weapon Napoleon recognized with respect, even though he had never before seen one outside of a museum: an Ithaca 12-guage double-barreled shotgun with twelve-inch barrels and a hand grip like that of an old dueling pistol.

"They outlawed those thing forty years ago," Napoleon said. "Too convenient for bank robbers."

The old man chuckled. "Well, they were advertised for home defense, and this one works right well. Don't either of you make any sudden moves, or I'll splatter you all over this side of the hanger. Now then, what brings you here?"

"Why, we received a message from Forbes, saying all agents were wanted here," Napoleon improvised smoothly. "We're from the Dubuque Satrapy, but we've been working with the Milwaukee group. I'm afraid we're a little late; we had trouble finding the place."

Napoleon was thinking furiously. This must be the Thrush caretaker. If he was alone here, then the dirigible was either being moved or was out on a trial run. Only one man—surely he and Illya could overpower him. Have to do it carefully, though; at this range, a double-barreled shotgun loaded with buckshot was the deadliest possible weapon.

The caretaker snorted. "You'll not take in old Ezra Sanders that easily. If you belong here, what were you doing with those guns?"

"Nobody answered the gate, and we had to crawl over the fence. We thought something was wrong."

Sanders appeared to be considering the statement. "Might be. Been something wrong with that call button on the gate these past few days; I think Andy pushed it too hard."

Napoleon sighed with relief and shifted position, then stiffened as the Ithaca was jabbed in is direction. "Might be ain't is!" the caretaker snapped. "You two just stay put while I think a bit."

"While you're thinking, could you tell us how they get the dirigible in and out of here?" Illya asked. "They surely don't slide the roof aside."

"Nah, that roof's solid. What we got is a big overhead door at one end. You know, one of them sectional things that slides up on tracks. Camouflaged real nice on the outside; looks like rocks and stuff. Had a hell of a time getting one big enough. But that roof, now that's real rock, with steel below. You could graze cattle up there," he said proudly.

Illya shifted position to ease an overburdened leg, and was rewarded by having the gun swivel to cover him. "Sonny, when I tell a man to stand still, I mean for him to be still," Sanders said.

"Where is everybody?" Napoleon demanded, assuming an authoritative air. "Forbes said this was urgent; why don't you take us to him instead of wasting time talking?" He can identify us."

"Forbes ain't here, and neither is anybody else but me. They took the dirigible out just a few hours ago. They ain't gonna be back, neither, so taking care of you two is up to me. Lessee now, if you're from Dubuque you got identification. Beard's a bureaucrat at heart; all his boys are loaded down with cards and countersigns. Let's see your identity card."

"Certainly," said Napoleon, reaching for his inside coat pocket.

"No sudden moves," said the caretaker. The Ithaca swung to point directly at Napoleon's stomach, and his hand halted abruptly. "Now then," Sanders continued, "just slip that identification out nice and easy, and toss it over to me so I can look at it."

Napoleon slipped his wallet out of his pocket and gingerly tossed it toward the caretaker's feet. At it struck the ground there was a muffled pop and a cloud of gas shot up to engulf the old man. Illya and Napoleon leaped sideways as a double charge of buckshot ripped though the space where they had been standing. Charging forward, Illya grabbed Sanders from behind while Napoleon wrestled the gun away from him. As soon as Napoleon had the gun, both agents released the man and stepped back, leaving the caretaker to stand with his eyes streaming tears and his mouth streaming profanity.

"Good work, Napoleon," Illya said. "I never really thought that tear gas cartridge in the wallet would ever be useful. Powerful stuff." He wiped his own eyes and retreated a trifle further.