THE VOICE IN GERTRUDE'S EARPHONES said, "Infrared shows a building to the north. It must be the monastery, so I am starting the count-down: ten, nine, eight, seven..."

On seven Gertrude pulled the first lever. There was a smooth sliding noise as the charge of explosive slipped under her seat.

"Six, five, four, three..."

Gertrude pulled the second lever firing the explosive bolts. The canopy shot away.

"Two, one, go!"

Gertrude pulled the third lever, firing the explosive charge under her seat. She felt an intense jolt as she was ejected from the jet plane. She had bailed out at 40,000 feet and 600 mph. Hitting thin air at 600 mph is a little like making a 100 foot dive into ice water. There was an intense deceleration and, despite the supposedly perfect aerodynamic balance of the ejection seat, she went into a spin.

The bright moon and stars were flashing blurs in her sight. The spin slowed and Gertrude pulled the fourth lever, separating herself from the ejection seat. She tumbled free and assumed the normal skydiving position. She was falling in total darkness; the ground below showed no lights, no hint of how far she had to fall. There was no choice but to hope the automatic release was accurate. If she panicked and pulled the manual release, she could die of exposure during the long fall.

Her parachute should open five minutes after ejection, but it seemed she had been falling half the night. It was not pleasant to think of what would happen if the automatic were miss-set. It took considerable will power to keep her hand off the manual release as time dragged on.

There was a sudden snap and swish. CIA parachutes are designed to open without a loud and possibly betraying pop. The chute did not jerk Gertrude, but with a steadily increasing pull it slowed her fall to a gentle downward drift. Gertrude wished she could see: if she was drifting straight down, well and good but if there was a ground wind her landing would be dangerous.

Fortunately the ground Gertrude hit was fairly flat, for there was a strong ground wind. Gertrude lacked the skill needed to collapse her chute and it dragged her along the rocky ground like a wild horse. She pulled furiously at the parachute disconnect lever, but nothing happened. In despair she pulled the manual release level and was promptly disconnected from her chute. It was a good thing Gertrude had trusted the automatic release, since she had confused the levers for opening the parachute and for disconnecting from the parachute.

Gertrude lay on the ground catching her breath and having unkind thoughts about the Air Force. Here she was a poor hard working spy, and they had given her a bailout system with six levers. There were, let's see, 720 different sequences in which one could pull the levers, one sequence which was extremely dangerous and 719 which were instantly fatal.

Still, there was one good thing about the ejection system: it included a back pack oxygen system. With a mean elevation of 14,000 feet, Tibet was justly called the roof of the world. Now it was time for Gertrude to find out if she could breathe here. When the Chief decided Gertrude should go to Tibet because she could speak the language, he had expected his subordinates to arrange such details as breathing. The best the CIA doctor could do was to teach Gertrude an adaption procedure, which would protect her from shock due to sudden change. Gertrude removed her oxygen mask and began the procedure.

Her ugly body was quite strong, and Gertrude was confident it would meet these new demands. Midway through the adaption procedure she began to feel some doubts. Perhaps the makeup man had been right after all. Gertrude and he had disagreed as to the best disguise. Gertrude held that the best was the least. Since she was stocky, and had brown eyes and black hair, all she needed to look like a native was skin coloring and a slight touch to make her cheekbones more prominent. The makeup man had insisted on making Gertrude into an old woman. That way her breathing trouble and weakness would be less conspicuous. At the time Gertrude had been insulted, now she was thankful.

Dawn came at these high altitudes suddenly, like thunder from the east. Gertrude gazed about at the desolate tundra, a vast rocky barren waste. Though bitter cold it was not frozen for lack of water.

This was the Chang Tang. The lawless nomads who dwelt in this great flatland had never been subdued by the Dalai Lama's government or its Chinese Communist successor. It was strange that men could live in this hostile land, stranger still that they should fight over it. The air on the planet Mars was considerably thinner, but Mars was no colder nor dryer than the Chang Tang.

A spy's first business is to avoid detection. Gertrude walked after her parachute which had not blown far. As she wadded it between a pair of rocks, she decided this first part of the mission was probably a success. The Chinese radar network around Tibet was full of holes and outdated. It was not at all likely they had spotted her plane, which had the latest stealth system. Her arrival might be betrayed by the ejection seat, but it was a mottled dull brown and would not be noticed from any distance.

The only remaining problem was the oxygen pack, which she had planned to hide but would probably need. With a little work Gertrude contrived to hide it under the shapeless sheepskin robes she wore. It was a little like hiding a large sign saying: "I am an American Spy, Please shoot me" under her robes. Still if the Chinese Communist troop she met did not suspect her, all would be well. If they did decide she was suspicious, they could probably not search her, but kill her out-hand.

Gertrude's local contact was in a monastery ten miles to the south. As Gertrude began her hike, she reviewed her possible cover stories.   How could she reach her contact without creating suspicion, without attracting attention. Did she dare claim to be a blood relative? There might be total lack of resemblance.

All she knew about her contact was his location, his name, Jar Quinan, and his code word. To identify herself to him she was to say: "It is time for the rising of the moon." He would reply: "The poppy does not grow on the roof of the world."

What business would plausibly bring an old woman to this remote monastery? It would be better if her business could be explained in a few words. Gertrude's Tibetan was not completely without accent. One scheme came to mind. Stagger up to the first monk she saw, gasp Jar Quinan's name and pretend to faint.

After three miles Gertrude paused and breathed oxygen for a few minutes. She didn't feel any need for the oxygen but the doctor had recommended this procedure. She hiked another three miles, thinking hard but finding no satisfactory plan. Pretending to faint might work but it lacked style.

Suddenly she spotted the monastery. There was a mountain four or five miles to the south-southwest. Halfway up the mountain on the side of a sheer cliff stood a large black stone building. The spot was so inaccessible that an eagle would have trouble building a nest there. How the monks built the monastery was a mystery; how Gertrude was to get there was a greater mystery.

It was time to use oxygen again, but the danger of being seen was too great. She walked on, fumbling in her robes for her binoculars. The silly things didn't want to focus; Gertrude's fingers seemed to be thumbs. At last the image became sharp but she had trouble holding the binoculars steady. Gertrude sensed that she was becoming clumsy, unco-ordinated, but this triggered no sense of alarm. There appeared to be a well at the foot of the mountain. Gertrude returned the glasses to their hiding place in her robes, nearly dropping them in the process. She walked on toward the well.

With each step her stride became more irregular, her balance more uncertain. Fog was slowly closing in on her brain. There was an important problem she must solve, something to do with her business at the monastery, but what? She reeled, staggering toward the well. There were three figures in black around the well. As Gertrude approached them, she gasped: "Please, Jar Quinan", and fell limply to the ground.

Darkness quickly filled her mind.