Only occasionally, when they were waiting for something, did he notice a difference. The forceful, all-competent manner changed. The blue eyes became frenzied and crazy, and dark shadows crossed her face like demons.

It was happening now. They were at the surface, and the giant elevator doors were ready to release them to the outside air. Melissa should have been bubbling over with energy and excitement. Instead she was withdrawn, staring at the floor a few feet in front of them as if she saw all the devils of Hell in the pattern of tiles. It was Drake who was wide-eyed and curious, too absorbed to worry about the change in Melissa. Even the doors themselves aroused his interest. They had not opened, like normal doors, but seemed to dissolve to gray mist and then quietly vanish. Was this what the induced teaching meant, when it referred to “the transforming technology provided by a mastery of molecular bonds”?

He stared through the doors as they silently faded. Half a dozen possibilities filled his mind as to what he might see outside: a world completely paved over, with roads and vehicles everywhere? vast amounts of airborne traffic of strange and unfamiliar design, flying above his head? postnuclear devastation? gigantic buildings, arcologies in which half a million people could live? shimmering heat, as global warming ruled; or sheeted ice and visible breath, the precursors to some new Ice Age held at bay in his own time only by the widespread burning of fossil fuels? Or maybe the ozone layer was lost, and sunlight was now so fierce and strong in ultraviolet radiation that unshielded skin would turn purple black within minutes.

All these, and more, had been confidently predicted.

Drake looked. He saw an endless prairie, dotted in the distance with small clumps of trees. Of humans, and human influence, there was no sign. Melissa came to his side and took his hand. He glanced at her and saw that she was back once more to her usual confident self. She began to lead the way, walking toward that far-off blue-gray skyline.

As they went, Melissa explained. She had returned to her normal manner instantly, as soon as the doors were fully

open and the surface beyond was visible.

“I could certainly see the signs in my time,” she said, “and I’d be surprised if they weren’t already visible in yours. If I was asked to provide a single word for what started the change, I’d give one that I’ve never seen quoted: glass. Before people had glass, there was a time when they didn’t have buildings at all. They lived outside, in the middle of whatever was out there — animals of all sizes, from fleas to elephants. They might not have liked it, but they couldn’t do a thing about it. As time went on people learned to make buildings and could live indoors. But if you wanted to see what you were doing, there had to be holes in the walls to let in light. You could make the holes small, so the elephants and wolves and bears couldn’t get in. But there was no way of making the holes big enough to let light in, yet small enough to keep insects and spiders and wood lice and centipedes out. People still expected to live in the middle of bugs of all kinds. So they squashed them, or encouraged them — spiders will keep your house free of flies — or just put up with them.

“But then cheap, good-quality glass became available. You could make windows that let the light in and kept the bugs out. And that’s when people started to think that spiders and cockroaches and ants were ‘dirty,’ and even ‘unnatural.’ I’ve known women who would scream if they found a decent-sized spider in their bathroom. And as for doing this—”

She reached down to the tall grass at their feet, and stood up again holding a big grasshopper gently in her cupped hands. “I knew people who wouldn’t touch a harmless bug like this, not if you paid them. Don’t you think it’s peculiar, even the word dirty changed its meaning. We’re walking on dirt. Dirt is everywhere. It’s totally natural. The ground is made of dirt. But when you live in a totally artificial environment, shielded from the outside, you never see real earth. ‘Dirty’ things become completely unnatural, and you avoid them. The good news is, when people wanted less and less to go outside, because it was full of beetles and gnats and worms and earwigs and leeches, they were willing to let the surface become more like the way it used to be before humans took over.” She bent down, released the grasshopper, and pointed away to their left. “Not just grasshoppers and bees and flies, either.

Go twenty to thirty kilometers that way, you’ll find gazelles and wildebeest and cheetahs. Maybe lions, too.”

“Are we in the tropics? Or has the climate changed?” One other confident prediction of Drake’s own time had been that in another generation all the hoofed wildlife and the big predators would be gone.

“We’re in what used to be Africa, about ten degrees north of the equator. It’s what you would call Ethiopia. There has been some climate change, too. Think of this as just like Serengeti, even though it isn’t.” Melissa pointed again, this time upward toward the afternoon sun. “One reason it’s not too hot, it’s midwinter and we’re fifteen hundred meters above sea level. Feel it in your lungs?” And, as Drake drew in a deep breath of thin but warm and pollen-laden air, she added, “Come on. You’ve been stuck inside for four years, or maybe it’s five hundred and four. Let’s see what sort of job they did when they tuned up your body.”

She had given up the usual gray dress in favor of bright pink shorts and a red T-shirt. Her legs were shapely but well muscled. She began to run toward the nearest grove of trees, maybe a mile and a half away. After a moment Drake set out in pursuit. They were each carrying a backpack, which when Drake had put it on seemed to weigh next to nothing. Within the first quarter of a mile he changed his mind. He could feel it bouncing up and down on his back, the straps cutting into his shoulders. How could a meal weigh nothing when it was on the inside of you, and so much when you were carrying it on the outside?

He began to pant harder and felt in his calves and thighs the first pain of fatigue and oxygen starvation. The altitude made a tremendous difference, far more than he would have expected, and he had not taken regular exercise since he was thawed. His new body was supposed to make it unnecessary. He forced himself to run for another couple of minutes, then he had to stop. He had forgotten what it was like to be physically exhausted. He dropped heavily to the ground, and lay there panting on the dry, grassy soil.

All the time that he was running, Melissa had steadily increased her lead. She went all the way to the trees, circled them, and headed back at the same speed. She came to where he lay and stood by him with her legs wide apart and her hands on her hips.

Drake rolled on to his back and stared up at her. “What did they do with your body?”

“Not a thing. This is the original me.” She squatted at his side. She wasn’t even panting. “Now do you agree that it was a good idea to get you away from work for a while?”

“If it doesn’t kill me when my heart gives out.”

“It won’t. Any problems like that would have been taken care of. Come on.” She reached down and helped him rise to his feet. “We have to keep going if we want to get to a monitor lodge before darkness.”

That sounded to Drake like an excellent idea. Lions might be twenty kilometers away. But how far were they likely to travel when they were hunting?

Melissa didn’t seem worried, although fast and fit as she was she could not outspeed a hungry lion. On the other hand, it occurred to Drake that she didn’t have to. All she had to do was run faster than him.

Drake’s idea of Earth’s future transportation system, if he had had one at all, was vague, busy, and grandiose — the chaotic vehicle mix of the late twentieth century, extrapolated to become faster, busier, and more tangled.