If the quiet open prairie had not set him right during the afternoon, Melissa did so that night. “The transportation system is all there,” she said, “and according to the reports it’s an excellent one. You can get anywhere in the world in just a few hours. We’ll see it for ourselves when we use it tomorrow. But it’s not heavily used. A few sightseers like us; and that’s about it.”

They had settled into a comfortable lodge, empty except for service machines, and they were eating dinner. It was Drake’s fourth meal with another human being since he had been resurrected. After three years of work together, Par Leon had shyly asked Drake if he would like to have dinner in person every three or four months. Drake took that for what it was, a sincere gesture of approval and friendship.

“So what happened?” he asked Melissa, as their empty plates vanished into the table. “I know that the population is down by a factor of ten from our time, but there still ought to be lots of traffic — people and goods. Why isn’t there?”

She sighed, with the tolerance of a person with a full stomach. Although she was smaller than Drake, she had eaten at least twice as much. But there was no fat on her body. He put it down to her high burn rate and her endless energy.

“You really did tune out for four years, didn’t you?” she said. “It must take a positive effort not to know what’s going on in the world.”

“I was planning to learn a lot about transportation systems, on this planet and off it. But not yet.”

“There’s less to learn than you might imagine. We could have guessed this, too, if we’d bothered to think. Why do people need transportation?”

“To carry goods from where they’re made to where they’re needed. To take people to work, and to let them meet each other.”

“What you’re describing is nowadays called a primitive industrial society. You and I lived at the end of that, though I don’t think we knew it. Automated manufacturing and telework were just about to take off in our time. We are now in a postindustrial, machine-supported society. You don’t need to carry goods when they can be made on the spot from simple raw materials. The manufacturing is all done by machines, smart enough so they don’t need people to watch over them. People still work, but no one goes to work anymore. They don’t need to. You must know that from your own project. You told me you don’t actually see Par Leon more than once a month, and you could get by very well without that.”

“So why is there a transportation system at all?”

“Because a few people want one and use one. Because it doesn’t really cost anything to maintain it — the machines do all that, without a single human being involved. Same as this lodge. When we arrived, our meals were cooked and our beds prepared, and we didn’t even have to request it. It’s an odd thought, but if all the people were to die, the housekeeper here probably wouldn’t notice. It would carry on as usual. I doubt if there’s another person — I mean on the surface — within a hundred miles.”

Drake went to the window and gazed out into the warm African night. It was bright moonlight, and fifty yards away he could see head-high grass swaying as some large invisible animal moved through it.

No other humans within a hundred miles of here. But there was a deeper question. What was he doing here?

He could not give an answer that made sense. Somehow, Melissa Bierly’s requests carried the weight of absolute commands. He did not know how to refuse. If she told him to go outside and face hungry lions, he was sure that he would do it.

And there was another question. What was she doing here? Her desire to see the world made sense only if she was looking for something — or running from something.

He could not imagine what; but later, when they were lying side by side in the lodge’s quiet bedroom, he heard her

sighs. Melissa was moaning softly in her sleep. And every few minutes, until he finally fell asleep himself, he heard the sound of grinding teeth.

Morning restored Melissa’s cheerfulness and drive. She announced that she had changed her mind. She wanted to head upward, to the top of the peak that loomed to the northeast, before they used the transportation system and flew to South America.

“Birhan?” Drake had called up a large-scale map and asked for an optimal route. Now he called up a topographic map. “Are you sure? It’s a brute. According to this it rises above thirteen thousand feet. We won’t be able to breathe.”

“I’ll breathe for both of us.” Melissa was bursting with energy. “I’ll help you, and we won’t go all the way to the top. Just enough to get a view. Come on, let’s go.”

The housekeeper had anticipated their need for packaged food, just as it had provided breakfast and had a car ready. It knew which maps Drake had demanded, and it had decided that Birhan was not within a day’s walk for a human.

The hovercar moved smoothly, about three feet above the surface, and made almost no noise. It handled all kinds of terrain with ease, water as well as land. When they drifted across the rocky near-dry course of a broad river, Drake looked up from the display that was tracing out their path.

“This is the Blue Nile. I wonder what happened to it.”

“Diverted, four hundred years ago.” As usual, Melissa knew everything. “It was once completely dry. It looks as though the old dams are breaking down. No one needs them anymore.”

The ground was rising steadily, and the hovercar was following the upward slope effortlessly. So far as Drake was concerned he would have been happy to ride all the way to the snow-capped peak ahead. Melissa had other ideas.

“This will do.” She stopped the car. “We’re at eight thousand feet. Let’s head for that, and eat when we get there. The car will stay here.”

She was pointing, not at the mountain but at the display. It showed a small flattened area where the hillside leveled off about two thousand feet above them. It could be approached easily from one side, but the contour lines suggested that the other edge ended in a sheer thousand-foot drop.

Melissa jumped lightly down from the car. Drake did the same, less lightly. He flexed his shoulders. Already he was aware that his lungs were working harder.

They started up. Melissa seemed to have an instinct for the easiest route, and rather than competing, Drake stayed two paces behind and followed her lead. He was afraid that it would be worse than the day before, but Melissa held to a slow, steady pace that he could live with. They were both wearing heavier clothing. Melissa had on thick blue pants and a padded jacket that exactly matched the color of her eyes. Drake wondered how the lodge housekeeper had made or found the color — how it even knew the color.

Today, at this altitude, warm clothes were necessary. Drake felt the tingling in his ears. The breeze at his back was chilly, but it seemed to help by pushing him along.

Helped for a while, at least. He was still relieved when they breasted the final rise and emerged onto the little plateau. Melissa did not stop, but went walking over to the far side of it.

“There,” she said. “That’s why we’re here. That’s Africa.”

She was pointing out to the west. Drake came to her side, then at once stepped back, appalled. The view was incredible. He could see what seemed like hundreds of miles across hills and plains. But they were standing at the very edge of a sheer cliff. It was so steep, it could not be natural. Someone, sometime, for some inexplicable reason, had sheered the whole mountain side to a rock face that dropped vertically without ledges or breaks to a boulder-strewn chasm a thousand feet below.

“Be careful, Melissa.” He backed farther and sat down. There was a gusty wind blowing on the plateau, and to be anywhere near the edge was terrifying.