She turned and grinned at him. “You don’t need to worry about me. Watch.”

While he stared in horror she closed her eyes and walked along the very edge, so close that at each blind step only a part of her foot met the rock. When he was convinced that she must fall, she turned and sauntered over to him.

“All right, then. Lunch?”

“Lunch, dinner, anything you like — as long as you stay away from that edge.”

“You worry too much, Drake.” She sat down casually at his side. “Can’t you see I could do this sort of thing all day, and never get hurt?”

He believed her, but to his relief she followed his lead and removed her backpack. He looked across to the other side of the plateau, with its easy descent. With any luck Melissa would feel they had done enough climbing for the day.

They began to eat. Even in midwinter, the sunlight at this latitude was intense. It picked out every detail of Melissa’s face: the contented smile, the glow of perfect skin, and the dazzling blue eyes. Drake decided that he had never in his life seen a woman who looked healthier.

He was staring right at her when the change came. She had just crunched a crisp piece of celery. As she swallowed, the corners of her mouth turned down. Her face flushed darker, responding to a sudden rush of blood. The splendid eyes stared fixedly at nothing, then glared all around.

“It has to be,” she said. “It has to be.”

She stood up. While Drake sat frozen she walked back five steps. He was still trying to scramble to his feet when she ran forward and hurled herself over the sheer edge of the cliff.

“Melissa!” He forgot his own fears and ran to the edge.

She was falling, her arms held wide. She did not change her position, and she did not cry out. Drake stared in horror as her blue-clad figure diminished in size. Already she had dropped hundreds of feet. Her pose was a swan dive, perfectly balanced like a high diver in the first phase of descent. But instead of water, beneath her lay nothing but solid rock and sharp-sided boulders.

When nothing in the world could save her, the whole cliff face erupted suddenly from top to bottom. It threw off a cloud of dust atoms like a shaken carpet. Instead of falling or spreading, the particles converged to form a dense gray plume that coalesced further as it swooped after Melissa’s plummeting body. When it was in the right position, it spread to form a gray blanket beneath her.

She must have seen it coming. She began to scream and flail, trying to avoid contact with the gray layer by changing the line of her fall. It was no good. The blanket reached her and folded itself about her. Drake saw her arms, protruding from the swaddling cover and beating at it desperately.

The downward plunge had been arrested. While he watched, the gray cylinder of blanket moved rapidly to the right, away from the main body of the mountain. In less than a minute it had vanished from his sight.

Drake stared down. Melissa was gone, but the rocky landscape at the foot of the cliff seemed to crawl and surge below him like an oily sea. His legs were too weak to support him. He cried out, and dropped to the rough surface of rock and gravel. He scrabbled at it with his fingers, trying to pull himself away from the edge.

He was still sitting, staring blindly into the fierce winter sunlight, when a wingless craft drifted down to his side.

“It’s all right, Drake.” Par Leon was inside the air-car. His voice was apologetic. A stony-faced woman was at his side. “Everything will be all right. We’re going to take you home.”

The woman’s name was Rozi Tegger. Par Leon made it clear, more from his body language than his comments, that she was not a close friend. Both he and Tegger were handling Drake with great care, responding to his dazed questions as the aircar flew them home.

To Drake, only two questions really mattered: Is she alive? Is she all right?

“Melissa Bierly is certainly alive,” Tegger replied. Leon yielded to her the first phase of explanation. “However, she is far from all right.”

“She’s hurt?”

“Not at all. Neither of you was in real danger, though we didn’t want you to know it. You were monitored from the moment that you left the lodge.”

“The hovercar?”

“That, and more than that. And far smaller. The automated safety service makes its own observing and protection units, and there were many billions of them in use all around you today. The ensemble that saved Melissa, after she threw herself off the cliff, is fairly typical. Each unit masses only a fraction of a gram. Each has sensors, flight capability, and real-time communication that allows all units to act in concert. Melissa tried to steer herself away from them and fall headfirst onto the rocks; but in reality she didn’t have a chance.”

“I saw, but I don’t understand. Melissa had everything to live for. Why would she try to kill herself?”

Par Leon and Rozi Tegger stared at each other. The tension in the car could not be missed.

“You have to tell him, you know,” Leon said. “If you don’t, I will. If you weren’t prepared to do this, you never should have started.”

“I never thought it would turn out this way.”

“Nor did I; but it did.”

“I know, I know.” Rozi Tegger sighed. “Very well, I’ll do it.” She turned to Drake. “How much did you learn from Melissa Bierly of her background?”

“I know that she was born one year before I entered the cryowombs. I know that she lived for twenty-four more years, then died and entered the cryowombs herself.”

“And that is all?”

“All I remember.”

“Very well.” Rozi Tegger, like Par Leon, could have been any age. She had thick, chestnut-brown hair, and now she ran her fingers through it. “Let me begin at the real beginning, fifteen years before Melissa Bierly was born.

“The structure of DNA had been known for fifty years, and the first mapping of the human genome had just been completed. Molecular biologists were riding high. A few people were already worrying about the ethical problems involved in playing with human genetic structure, but none of the rules that we have now had been put in place. In fact, to our eyes your original time is most perplexing. Those who felt comfortable about gene manipulation to cure disease were often the same people who were strongly opposed to mandatory genetic selection to avoid disease. Eugenics was a socially unacceptable word.

“When technology flourishes and suitable laws are not in place to constrain its uses, there will surely be trouble.

“A group of scientists with strong social and political goals decided to employ the emerging technology to benefit the human race. They were well intentioned, we do not dispute that. They were also permitted to operate with a freedom unthinkable today. They saw ways to modify the human genome so as to create persons stronger, more intelligent, more long-lived, and more resistant to disease. That is what they did.”

“Superman,” Drake murmured. But he did so in English, and Rozi Tegger frowned at him in confusion.

“Superior men,” Drake added, this time in Universal. “Supermen.”

Tegger nodded. “And superior women. Do I have to say more? We did not change the body of Melissa Bierly upon resurrection, as yours was changed. We did not need to. You saw her, yet you were exposed to little of her full potential. She could run to the top of Birhan, or mountains far higher than that, without breathing equipment and without feeling fatigue. She could spend a winter night naked amid mountaintop snow and ice, and come down unharmed. She could hang from the cliff where we found you by one finger, hour after hour.

“But those are mere physical improvements, and we judge them trivial. Of far greater interest are the mental characteristics of Melissa Bierly and others like her. She has outstanding intellect. In two months she has come to understand more of this time, and what is in it, than most of us. She mastered access to the general data banks as though born to them. She became conversant with a dozen languages, from Economics to Astronautics, and made their cross-connections with ease.