"I'm sorry," Stern was saying, "but this isn't my affair. I only signed on to the Professor's team because my girlfriend was going to summer school in Toulouse. I'm not a historian. I'm a scientist. And anyway, I don't think it's safe."

Doniger said, "You don't think the machines are safe?"

"No, the place. The year 1357. There was civil war in France after Poitiers. Free companies of soldiers pillaging the countryside. Bandits, cutthroats, lawlessness everywhere."

Marek nodded. If anything, Stern was understating the situation. The fourteenth century was a vanished world, and a dangerous one. It was a religious world; most people went to church at least once a day. But it was an incredibly violent world, where invading armies killed everyone, where women and children were routinely hacked to death, where pregnant women were eviscerated for sport. It was a world that gave lip service to the ideals of chivalry while indiscriminately pillaging and murdering, where women were imagined to be powerless and delicate, yet they ruled fortunes, commanded castles, took lovers at will and plotted assassination and rebellion. It was a world of shifting boundaries and shifting allegiances, often changing from one day to the next. It was a world of death, of sweeping plagues, of disease, of constant warfare.

Gordon said to Stern, "I certainly wouldn't want to force you."

"But remember," Doniger said, "you won't be alone. We'll be sending escorts with you."

"I'm sorry," Stern kept saying. "I'm sorry."

Finally Marek said, "Let him stay. He's right. It's not his period, and it's not his affair."

"Now that you mention it," Chris said, "I've been thinking: It's not my period, either. I'm much more late thirteenth than true fourteenth century. Maybe I should stay with David-"

"Forget it," Marek said, throwing an arm over Chris's shoulder. "You'll be fine." Marek treated it like a joke, even though he knew Chris wasn't exactly joking.

Not exactly.

The room was cold. Chilly mist covered their feet and ankles. They left ripples in the mist as they walked toward the machines.

Four cages had been linked together at the bases, and a fifth cage stood by itself. Baretto said, "That's mine," and stepped into the single cage. He stood erect, staring forward, waiting.

Susan Gomez stepped into one of the clustered cages, and said, "The rest of you come with me." Marek, Kate and Chris climbed into the cages next to her. The machines seemed to be on springs; they rocked slightly as each got on.

"Everybody all set?"

The others murmured, nodded.

Baretto said, "Ladies first."

"You got that right," Gomez said. There didn't seem to be any love lost between them. "Okay," she said to the others. "We're off."

Chris's heart began to pound. He felt light-headed and panicky. He balled his hands into fists.

Gomez said, "Relax. I think you'll find it's quite enjoyable." She slipped the ceramic into the slot at her feet, and stood back up.

"Here we go. Remember: everyone very still when the time comes."

The machines began to hum. Chris felt a slight vibration in the base, beneath his feet. The humming of the machines grew louder. The mist swirled away from the bases of the machines. The machines began to creak and squeal, as if metal was being twisted. The sound built quickly, until it was as steady and loud as a scream.

"That's from the liquid helium," Gomez said. "Chilling the metal to superconduction temperatures."

Abruptly, the screaming ended and the chattering sound began.

"Infrared clearance," she said. "This is it."

Chris felt his whole body begin to tremble involuntarily. He tried to control it, but his legs were shaking. He had a moment of panic - maybe he should call it off - but then he heard a recorded voice say, "Stand still - eyes open-"

Too late, he thought. Too late.

"-deep breath - hold it… . Now!"

The circular ring descended from above his head, moving swiftly to his feet. It clicked as it touched the base. And a moment later, there was a blinding flash of light - brighter than the sun - coming from all around him - but he felt nothing at all. In fact, he had a sudden strange sense of cold detachment, as if he were now observing a distant scene.

The world around him was completely, utterly silent.

He saw Baretto's nearby machine was growing larger, starting to loom over him. Baretto, a giant, his huge face with monstrous pores, was bending over, looking down at them.

More flashes.

As Baretto's machine grew larger, it also appeared to move away from them, revealing a widening expanse of floor: a vast plain of dark rubber floor, stretching away into the distance.

More flashes.

The rubber floor had a pattern of raised circles. Now these circles began to rise up around them like black cliffs. Soon the black cliffs had grown so high that they seemed like black skyscrapers, joining overhead, closing off the light above. Finally, the skyscrapers touched one another, and the world was dark.

More flashes.

They sank into inky blackness for a moment before he distinguished flickering pinpoints of light, arranged in a gridlike pattern, stretching away in all directions. It was as if they were inside some enormous glowing crystalline structure. As Chris watched, the points of light grew brighter and larger, their edges blurring, until each became a fuzzy glowing ball. He wondered if these were atoms.

He could no longer see the grid, just a few nearby balls. His cage moved directly toward one glowing ball, which appeared to be pulsing, changing its shape in flickering patterns.

Then they were inside the ball, immersed in a bright glowing fog that seemed to throb with energy.

And then the glow faded, and was gone.

They hung in featureless blackness. Nothing.

Blackness.

But then he saw that they were still sinking downward, now heading toward the churning surface of a black ocean in a black night. The ocean whipped and boiled, making a frothy blue-tinged foam. As they descended to the surface, the foam grew larger. Chris saw that one bubble in particular had an especially bright blue glow.

His machine moved toward that glow at accelerating speed, flying faster and faster, and he had the odd sensation that they were going to crash in the foam, and then they entered the bubble and he heard a loud piercing shriek.

Then silence.

Darkness.

Nothing.

In the control room, David Stern watched the flashes on the rubber floor become smaller and weaker, and finally vanish entirely. The machines were gone. The technicians immediately turned to Baretto and began his transmission countdown.

But Stern kept staring at the spot in the rubber floor where Chris and the others had been.

"And where are they now?" he asked Gordon.

"Oh, they've arrived now," Gordon said. "They are there now."

"They've been rebuilt?"

"Yes."

"Without a fax machine at the other end."

"That's right."

"Tell me why," Stern said. "Tell me the details the others didn't need to be bothered with.”

"All right," Gordon said. "It isn't anything bad. I just thought the others might find it, well, disturbing."

"Uh-huh."

"Let's go back," Gordon said, "to the interference patterns, which you remember showed us that other universes can affect our own universe. We don't have to do anything to get the interference pattern to occur. It just happens by itself."

"Yes."

"And this interaction is very reliable; it will always occur, whenever you set up a pair of slits."

Stern nodded. He was trying to see where this was going, but he couldn't foresee the direction Gordon was taking.

"So we know that in certain situations, we can count on other universes to make something happen. We hold up the slits, and the other universes make the pattern we see, every time."