Breathing a little heavily in the Andean air, and still dazed at the

　　urgency with which he had been whisked southward

via jet bomber

,

　　Dr. Luis Craig walked across packed earth toward a powerful-looking

　　helicopter which, he had just been told, was to take him on the last

　　leg of his trip. He listened tiredly to the unctuous words of his

　　escort, a Lieutenant Rabar who wore the uniform of this Latin American

　　nation's Air Force and who was to fly the helicopter.

　　Shouts erupted behind them, at the edge of the field. Something snarled

　　at his left ear. The sound was familiar, though not recently so: the

　　crack of a rifle. He hit the dirt.

　　Another bullet came searching, but now the shouts got themselves

　　organized into crisp Spanish. Sidearms and at least two automatic

　　weapons blatted. There were no more rifle shots. Cautiously, he raised

　　his head to look at the knot of uniformed men where the sniper had been.

　　Rabar stepped forward, offering a hand. "Are you all right, Doctor?"

　　Craig ignored the hand and got up without help. "Quite, thank you." He

　　had disliked Rabar from the moment of introduction; and now it was in

　　his mind that Rabar had stepped carefully away from him _before_ the

　　first bullet came.

　　As casually as he could, he walked to the aluminum ladder hung upon

　　the helicopter's side and hauled himself up. He stopped in the hatch,

　　dignity forgotten, startled at the disparity of the three men already

　　in the ship.

　　Directly across the cabin sat a gaunt scarecrow of a man in a black

　　priest's cassock. An oxygen mask dangled on his thin chest, suggesting

　　a bloated crucifix. The long, swarthy face was pockmarked, dour and

　　without animation at the moment, except for fierce black eyes that

　　burned steadily into Craig's own. Craig thought of a condor, perched

　　near some nearly ready meal. He was immediately ashamed of the thought.

　　Forward of the priest sat a brown Indian. His face mirrored dignified

　　resignation to being carried in this hellish contraption to horrible

　　death, or worse.

　　Occupying the only seat on the hatch side was a tautly uniformed man

　　who eyed Craig coldly.

　　The priest spoke. His voice was deep and gently strong, caressing the

　　Spanish syllables like a great soft bell. "We are abject, Doctor. We

　　had tried very hard ... but there are fanatics."

　　"Eh?" said Craig. "Oh. Well, I am unhurt, as you can see."

　　"For which, thanks to the Almighty. Our humblest apologies. You speak

　　Spanish exceptionally well, Doctor."

　　Wondering if there were a question behind the compliment, Craig said,

　　"My mother was Mexican." He did not think it necessary to add that he'd

　　grown up near the border, and had once spent two years as an exchange

　　Professor of Physics at the Mexican university.

　　The priest nodded once. "I see. It was thoughtful of your government

　　to choose you. And more than kind of you to come. But, forgive me;

　　the shooting has made me forget my manners. This--" indicating the

　　uniformed man--"is General Noriega." He laid a hand on the shoulder of

　　the Indian. "And this one prefers to answer to the name Dientes."

　　Craig looked at the brown face with interest. Archeology was one of his

　　hobbies, and in this part of the world ... 'Dientes' was Spanish for

　　'teeth,' he mused. Abruptly, under his gaze, the immobile face split

　　into a wide nervous smile revealing the source of the nickname. They

　　were large, even and very white.

　　"And I," the priest was saying, "am called Father Brulieres. Won't you

　　seat yourself?"

　　Craig tensed in surprise. The name Brulieres had been very much in the

　　news of late. A priest by that name had led the movement which put the

　　present government in power--and was still reputedly, the man who

　　actually ran it.

　　Craig realized he was still perched awkwardly halfway into the cabin.

　　Mumbling something, he squeezed his bulky mountain gear through the

　　hatch and took the empty seat beside the priest.

　　Rabar came in, closing the hatch behind him, and went forward to the

　　pilot's seat. He glanced around at his passengers.

　　It seemed to Craig that he was more interested in faces than in the

　　condition of seat belts. Rabar worked at switches and buttons. Engines

　　coughed, then roared. From overhead came the rising "whoosh" of the

　　vanes. The craft shivered and lifted.

　　They went on oxygen at once, and Craig, under the eyes of the other

　　passengers, was glad to put the breather over at least part of his

　　face. Imitating the others he pulled down the earflaps of his helmet.

　　It seemed to have built-in radio, as he could hear Rabar advising

　　them to strap in. A moment later, clearing his throat, he discovered

　　that his breather contained a mike. He was surprised at such advanced

　　electronics here.

　　They were quickly closed in by mighty cliffs. Below them, a river

　　tumbled wildly. Where it could find root-holds, fantastic greenery

　　burgeoned, but it did little to disguise the menacing rock. The

　　cabin's plastic windows gave all too clear a view.

　　Turning from the window beside him, Craig found his eyes wandering to

　　the insignia pinned to the priest's cassock. Of elegantly wrought gold,

　　it was the same emblem he'd noticed on buildings, vehicles and other

　　government property here. It looked like a set of football goalposts

　　with the uprights moved in close together, leaving the crossbar

　　extending to the sides.

　　The priest caught his look and gave him what might be intended for a

　　smile. "You wonder about our emblem? It represents the Church and State

　　standing--what is the expression in your own language?--'four-square'

　　together."

　　"Oh." Craig realized that the symbol was simply a cross with two

　　posts instead of one. He felt a little annoyed. His own government

　　had told him enough to make him eager to come on this job, but they'd

　　also warned him emphatically not to discuss politics or religion.

　　He supposed the United States needed friends wherever they could be

　　found, but a dictatorship wasn't his notion of a good alternative to

　　Bolshevism.

　　He realized that the warning had point. He didn't know how ruthless

　　these people might be, but the shooting back at the airfield hadn't

　　been any game of marbles. For that matter, the whole country, or what

　　he'd seen of it, had an armed-camp air.

　　He decided the thing to do was to concentrate on the scientific reason

　　for his visit, and now was as good a time to start as any. He leaned

　　toward Brulieres, then realized that wasn't necessary. "Er--are you at

　　liberty to tell me anything about the explosion?"

　　Brulieres eyed him for a moment, and again there was the hint of a

　　smile. "We could hardly be secretive with _you_, Doctor. You are the

　　expert. How much were you told?"

　　"Just that there'd been a nuclear explosion of unknown origin. They

　　said there was something spectacular about it."

　　"Spectacular? _Si!_ Your government was gracious enough to accept

　　our request for technical help without demanding details. Security

　　is very difficult, as you comprehend." Brulieres looked absent for

　　a moment. "The explosion occurred at a spot famous in pre-Christian

　　legends, which is why friend Dientes accompanies us. He is considered

　　_experto_." The intense eyes turned upon the Indian, with a hint of

　　mischief. "Not that he fails to be a good Christian as well."

　　The Indian crossed himself nervously.

　　"The explosion," Brulieres went on, "seems to have uncovered some very

　　ancient tunnels. We wish to explore them, but we felt we needed a

　　nuclear physicist along. Especially since there appears the possibility

　　that the explosion originated from the tunnels."

　　Craig heard Noriega clear his throat. Brulieres glanced at Noriega. "It

　　has also been suggested," the priest said, "that the uncovering of the

　　tunnels is coincidental, and that the explosion was of foreign origin."

　　Craig thought that over, and was annoyed. "That does not seem likely,"

　　he said, a little stiffly. "Nobody is tossing live warheads around."

　　Noriega spoke for the first time. His voice was crisp and rather high.

　　"You can perhaps speak for your own nation, Doctor Craig; but others

　　too possess missiles."

　　Brulieres interposed, "You no doubt know, Doctor, that a communist

　　putsch very nearly took over this country. The present government has

　　been compelled to very strict measures against a further attempt.

　　Therefore we are not popular with the communist nations."

　　Craig waved a hand impatiently. "Yes, I know that, but...." He realized

　　he was being careless. "I only wish to approach my investigation with

　　an open mind. You say the tunnels were ancient? Incan, perhaps?"

　　Brulieres shook his head slowly. "They were hardly capable of anything

　　on this scale. One cannot speak so surely of those who preceded the

　　Incas in this place."

　　Craig pondered, and felt his pulse move faster. "How much have you

　　learned so far?"

　　"What can be seen from the air. We will be the first to land, if you

　　decide it is safe."