Permutation City

"No. Zemansky's organized a hundred people to verify the launch from within. I don't have to be there."

Maria was horrified. "But -- why leave yourself out? Why risk it?"

He turned to her and said placidly, "I'm not splitting myself, not again. I had enough of that on twenty-four Earths. I want one life, one history. One explanation. Even if it has to come to an end."

The program he'd been running beeped triumphantly and flashed up a message. "There's a data port for granting physical interaction with one environment, and it seems to be intact."

Maria said, "Send in a few thousand robots, sweep the place for signs of life."

Durham was already trying it. He frowned. "No luck. But I wonder if . . ."

He created a doorway a few meters to his right; it seemed to lead into a lavishly decorated corridor.

Maria said queasily, "You have seven minutes. The port's not working: if a robot can't materialize . . ."

Durham stood and walked through the doorway, then broke into a run. Maria stared after him. But there was no special danger "in there" -- no extra risk. The software running their models was equally safe, wherever they pretended their bodies to be.

She caught up with Durham just as he reached an ornate curved staircase; they were upstairs in what seemed to be a large two-story house. He clapped her on the shoulder. "Thank you. Try downstairs, I'll keep going up here."

Maria wished she'd disabled all her human metabolic constraints -- but she was too agitated now to try to work out how to make the changes, too awash with adrenaline to do anything but run down corridors bellowing, "Is there anyone home?"

At the end of one passage, she burst through a door and found herself out in the garden.

She looked about in despair. The grounds were enormous -- and apparently deserted. She stood catching her breath, listening for signs of life. She could hear birdsong in the distance, nothing else.

Then she spotted a white shape in the grass, near a flowerbed full of tulips.

She yelled, "Down here!" and hurried toward it.

It was a young man, stark naked, stretched out on the lawn with his head cradled in his hands. She heard breaking glass behind her, and then a heavy thud on the ground; she turned to see Durham pick himself up and limp toward her.

She knelt by the stranger and tried to wake him, slapping his cheeks. Durham arrived, ashen, clearly shorn of his artificial tranquility. He said, "I think I've sprained an ankle. I could have broken my neck. Don't take any risks -- something strange is going on with our physiology; I can't override the old-world defaults."

Maria seized the man by the shoulders and shook him hard, to no effect. "This is hopeless!"

Durham pulled her away. "I'll wake him. You go back."

Maria tried to summon up a mind's-eye control panel to spirit her away. Nothing happened. "I can't connect with my exoself. I can't get through."

"Use the doorway, then. Run!"

She hesitated -- but she had no intention of following Durham into martyrdom. She turned and sprinted back into the house. She took the stairs two at a time, trying to keep her mind blank, then raced down the corridor. The doorway into the evacuation control room was still there -- or at least, still visible. As she ran toward it, she could see herself colliding with an invisible barrier -- but when she reached the frame, she passed straight through.

The clock on the interface window showed twenty seconds to launch.

When she'd insisted on hanging around, Durham had made her set up a program which would pack her into the new Garden-of-Eden in an instant; the icon for it -- a three-dimensional Alice stepping into a flat storybook illustration -- was clearly on display in a corner of the window.

She reached for it, then glanced toward the doorway into Riemann's world.

The corridor was moving, slowly retreating. Slipping away, like the buildings of the City.

She cried out, "Durham! You idiot! It's going to implode!" Her hand shook; her fingers brushed the Alice icon, lightly, without the force needed to signal consent.

Five seconds to launch.

She could clone herself. Send one version off with the rest of Elysium, send one version in to warn him.

But she didn't know how. There wasn't time to learn how.

Two seconds. One.

She bunched her fist beside the icon, and wailed. The map of the giant cube flickered blue-white: the new lattice had begun to grow, the outermost processors were reproducing. It was still part of Elysium -- a new grid being simulated by the processors of the old one -- but she knew the watchdog software wouldn't give her a second chance. It wouldn't let her halt the launch and start again.