"Illya and I will investigate. If everything goes well, we'll return to Kerry's car and drive back to join you. If everything does not go well, you"—he gestured to Kerry—"will press this button on the side of my communicator, say the magic words 'Open Channel D,' and make a full report to Mr. Waverly in New York. You will then follow his instructions. In the meantime, you, Lee, will prevent anyone from entering your house. That includes mail carriers, milkmen, your next-door neighbor, and your best friend. Anyone in this county could be a Thrush agent, and several people probably are. There are also innocent people about, so try not to kill anybody out of hand. But keep them out. Understand?"

Lee nodded.

"Fine. Now, we'll try to report at least every half hour. If two hours go by without a report, assume we're out of action and report to Mr. Waverly."

After seeing the girls safely off, Napoleon and Illya began to follow the track into the woods. It obviously wasn't a well-used thoroughfare; even where no effort had been made to hide it, there were times when the agents had difficulty following it in the waning light. Eventually, however, they rounded a final thicket and found themselves facing a large steel gate, set in the middle of a wire mesh fence that stretched off into the woods on both sides.

A large sign was fastened to the middle of the gate. WARNING! PRIVATE PROPERTY. TRESPASSERS WILL BE PROSECUTED TO THE FULL EXTENT OF THE LAW. Beneath this, in smaller letters, was the name TOTAL HARMONY REALTY UNDERWRITERS SOCIETY OF HURICON.

Illya pointed to the name, spelling out the initial letters. "T.H.R.U.S.H. They certainly advertise their presence, don't they?"

"Probably not expecting anyone but an occasional hunter and wanted something that sounded impressive," Napoleon responded. "Well, I suppose we have our choice: do we pick the lock or simply blast through a section of fence?"

"I wouldn't recommend either," Illya said, pointing to another sign to one side of the gate: WARNING! ELECTRIC FENCE. "You'll note the lock is wired into the electrical system; I suspect that failure on the part of either fence or lock rings an alarm somewhere." He pointed to a push-button set in the gate above the lock. "If you're in a hurry, I suppose we could ring the doorbell and see who answers."

Napoleon careful examined the lock and gate, and stepped back. "All right, mastermind; from the tone of that last remark, I assume you have something in mind."

"Of course. A good secret agent is prepared for any emergency." Illya removed a small package from his jacket pocket and began looking up and down the length of fence. "First, however, we need the proper setting—down that way would be best, I think."

Illya strode off to the left of the path, Napoleon following closely. About a hundred yards from the path, he halted and stared thoughtfully up into the branches of a large oak tree.

"This should do it. They've kept the brush trimmed back from the fence, but they didn't get all the tall trees in the area." He unwrapped his package with proved to be a length of heavy monofilament line with a miniature grapnel attached to one end. Swinging this around his head, he cast into the branches of tree. On the fifth cast, the grapnel caught and a careful test of the line showed it to be hooked solidly.

Napoleon had watched the proceedings with interest. "What's next, kimosabe?" he asked, although he had developed a strong suspicion and his hands were smarting from only the thought.

"Next we go up the line," Illya confirmed, suiting action to words.

When both agents were well up among the branches, Illya unhooked the grapnel. "Now for the hard part," he murmured as he cast the line toward an equally large tree thirty feet away on the opposite side of the fence.

It took patience, and it was almost totally dark by the time he had the line hooked to his satisfaction. Carefully, he tied the end around the trunk of the tree they were in. "Now," he explained cheerfully, "we swing across, hand over hand."

Napoleon felt the thin line again and winced. "There must be an easier way, Tarzan."

"Nonsense, Napoleon, a little exercise is good for you. Tones up the body. Come on, or it'll be so dark we won't be able to find the path again."

Inside the fence, Napoleon rubbed his aching palms. "When I go back, I'm going through that gate, one way or another. Let Thrush sue me for property damage."

By the time they had located the path again, the only light was from a half moon that tended to duck behind small clouds at just the wrong times. The path continued for another quarter of a mile, winding through scrubby woods and up and down hills.

"Looks like something up ahead," Illya said, squinting into the shadows.

Hurrying forward, they came to a large and rather battered shed, with windows knocked out and a roof that sagged dangerously. Here the trail apparently ended. They stared at the shed.

"It doesn't look like my idea of a dirigible hangar," said Illya.

"Let's check it out," Napoleon suggested. "Something made those tracks."

They circled the building warily. It remained enigmatic in the moonlight. The only positive result was to prove that the road definitely ended here at the shed, although the woods didn't.

Holding his U.N.C.L.E. Special ready for action, Napoleon cautiously approached the sagging door of the shed, and kicked it open with a sudden motion.

Nothing happened.

With Illya covering him, he stepped inside. Feeling a little foolish, he lowered his pistol. The shed was empty.

A moment later, Illya entered, and they stared about the interior. There was not even a partition to block the view. The inside of the shed was a large single room, containing nothing but a little dirt on the floor. A scrap of paper on one wall proved, when examined under Illya's flashlight, to be a page from a 1927 calendar.

Napoleon shook his head. "There's something wrong about this. We know this is a Thrush installation; the sign on the fence told us that much."

"You don't suppose there could really be such a company as the Total Harmony Realty Underwriters Society of Horicon, do you?" Illya asked. "What's a Horicon, anyway?"

"A marsh somewhere in the state—a sort of rest stop for geese during migration, I think. And probably a town, too. I remember seeing it on our list of part-time agents. But I somehow doubt the existence of the Society, at least this far from Horicon. No, we're missing something here."

Illya rapped his knuckles on a convenient wall, muttering, "Horicon, Mukwonago, Baraboo, Black Earth—don't we have agents in any normal-sounding towns? Like Minsk, or Pinsk, or Vladivostok?"

"Do that again," requested Napoleon, suddenly intent.

"Do what again? List our agents' addresses?"

"No, hit the wall."

Obligingly, Illya rapped the wall again. Napoleon nodded with satisfaction. "Notice anything?"

"Well, it sounded pretty solid."

"Exactly." Napoleon gave his section of wall a resounding kick. "See that? No give to it; like kicking a brick wall. Now at all in keeping with the rickety appearance of this shed. Maybe we're at the right place after all."

Illya was now peering more closely at the walls. "Notice something else? Look carefully at the walls and roof. See any cracks?"

"You're right. Solid joints everywhere. This place is built much more strongly than its appearance indicates." Napoleon removed a ball-point pen from his shirt pocket, pressed a concealed stud which opened it, and rearranged its contents into the form of a compact drill. "Got the idea from a TV commercial," he commented as the bit bored rapidly into the wood.