Chris Hughes said, "What's wrong with a Bic?"

"Not correct for the period. You can't take plastic back there." Gordon returned to the kit. "Then we have basic first aid, nothing fancy. Anti-inflammatory, antidiarrhea, antispasmodic, antipain. You don't want to be vomiting in a castle," he said. "And we can't give you pills for the water."

Stern took all this in with a sense of unreality. Vomiting in a castle? he thought. "Listen, uh - "

"And finally, an all-purpose pocket tool, including knife and picklock." It looked like a steel Swiss army knife. Gordon put everything back in the kit. "You'll probably never use any of this stuff, but you've got it anyway. Now let's get you dressed."

Stern could not shake off his persistent sense of unease. A kindly, grandmotherly woman had gotten up from her sewing machine and was handing them all clothing: first, white linen undershorts  -  sort of boxer shorts, but without elastic  -  then a leather belt, and then black woolen leggings.

"What're these?" Stern said. "Tights?"

"They're called hose, dear."

There was no elastic on them, either. "How do they stay up?"

"You slip them under your belt, beneath the doublet. Or tie them to the points of your doublet."

"Points?"

"That's right, dear. Of your doublet."

Stern glanced at the others. They were calmly collecting the clothes in a pile as each article was given to them. They seemed to know what everything was for; they were as calm as if they were in a department store. But Stern was lost, and he felt panicky. Now he was given a white linen shirt that came to his upper thigh, and a larger overshirt, called a doublet, made of quilted felt. And finally a dagger on a steel chain. He looked at it askance.

"Everyone carries one. You'll need it for eating, if nothing else."

He put it absently on top of the pile, and poked through the clothing, still trying to find the "points."

Gordon said, "These clothes are intended to be status-neutral, neither expensive nor poor. We want them to approximate the dress of a middling merchant, a court page, or a down-at-the-heels nobleman." Stern was handed shoes, which looked like leather slippers with pointed toes, except they buckled. Like court jester's shoes, he thought unhappily.

The grandmotherly woman smiled: "Don't worry, they have air soles built in, just like your Nikes."

"Why is everything dirty?" Stern said, frowning at his overshirt.

"Well, you want to fit in, don't you?"

They changed in a locker room. Stern watched the other men. "How exactly do we, uh . . ."

"You want to know how you dress in the fourteenth century?" Marek said. "It's simple." Marek had stripped off all his clothes and was walking around naked, relaxed. The man was bulging with muscles. Stern felt intimidated as he slowly took off his trousers.

"First," Marek said, "put on your undershorts. This is very nice quality linen. They had good linen in those days. To hold the shorts up, tie your belt around your waist and roll the top of the undershorts around the belt a couple of times, so it holds. All right?"

"Your belt goes under your clothes?"

"That's right. Holding up your shorts. Next, put on your hose." Marek began to pull on his black wool tights. The hose had feet at the bottom, like a child's pajamas. "They have these strings at the top, you see?"

"My hose is baggy," Stern said, tugging them up, poking at the knees.

"That's fine. These aren't dress hose, so they aren't skintight. Next, your linen overshirt. Just pull it over your head and let it hang down. No, no, David. The slit at the neck goes in the front."

Stern pulled his arms out and twisted the shirt around, fumbling.

"And finally," Marek said, picking up a felt outershirt, "you put on your doublet. Combination suit coat and windbreaker. You wear it indoors and out, never take it off except when it is very hot. See the points? They're the laces, under the felt. Now, tie your hose to the points of the doublet, through the slits in your overshirt."

Marek managed this in only a few moments; it was as if he'd done it every day of his life. It took Chris much longer, Stern noted with satisfaction. Stern himself struggled to twist his torso, to tie the knots at his backside.

"You call this simple?" he said, grunting.

"You just haven't looked at your own clothes lately," Marek said. "The average Westerner in the twentieth century wears nine to twelve items of daily clothing. Here, there are only six."

Stern pulled on his doublet, tugging it down over his waist, so it came to his thighs. In doing so, he wrinkled his undershirt, and eventually Marek had to help him straighten it all out, as well as lace his hose tighter.

Finally, Marek looped the dagger and the chain loosely around Stern's waist, and stood back to admire him.

"There," Marek said, nodding. "How do you feel?"

Stern wriggled his shoulders uncomfortably. "I feel like a trussed chicken."

Marek laughed. "You'll get used to it."

Kate was finishing dressing when Susan Gomez, the young woman who had taken the trip back, came in. Gomez was wearing period clothes and a wig. She tossed another wig to Kate.

Kate made a face.

"You have to wear it," Gomez said. "Short hair on a woman is a sign of disgrace, or heresy. Don't ever let anyone back there see your true hair length."

Kate pulled on the wig, which brought dark blond hair to her shoulders. She turned to look in the mirror, and saw the face of a stranger. She looked younger, softer. Weaker.

"It's either that," Gomez said, "or cut your hair really short, like a man. Your call."

"I'll wear the wig," Kate said.

Diane Kramer looked at Victor Baretto and said, "But this has always been a rule, Victor. You know that."

"Yes, but the problem," Baretto said, "is that you're giving us a new mission." Baretto was a lean, tough-looking man in his thirties, an ex-ranger who had been with the company for two years. During that time, he had acquired a reputation as a competent security man, but a bit of a prima donna. "Now, you're asking us to go into the world, but you won't let us take weapons."

"That's right, Victor. No anachronisms. No modern artifacts going back. That's been our rule from the beginning." Kramer tried to conceal her frustration. These military types were difficult, particularly the men. The women, like Gomez, were okay. But the men kept trying to, as they put it, "apply their training" to the ITC trips back, and it never really worked. Privately, Kramer thought it was just a way for the men to conceal their anxiety, but of course she could never say that. It was difficult enough for them to take orders from a woman like her in the first place.

The men also had more trouble keeping their work secret. It was easier for women, but the men all wanted to brag about going back to the past. Of course, they were forbidden by all sorts of contractual arrangements, but contracts could be forgotten after a few drinks in a bar. That was why Kramer had informed them all about the existence of several specially burned nav wafers. These wafers had entered the mythology of the company, including their names: Tunguska, Vesuvius, Tokyo. The Vesuvius wafer put you on the Bay of Naples at 7:00 a.m. on August 24, A.D. 79, just before burning ash killed everyone. Tunguska left you in Siberia in 1908, just before the giant meteor struck, causing a shock wave that killed every living thing for hundreds of miles. Tokyo put you in that city in 1923, just before the earthquake flattened it. The idea was if word of the project became public, you might end up with the wrong wafer on your next trip out. None of the military types were quite sure whether any of this was true, or just company mythology.

Which was just how Kramer liked it.

"This is a new mission," Baretto said again, as if she hadn't heard him before. "You're asking us to go into the world  -  to go behind enemy lines, so to speak  -  without weapons."

"But you're all trained in hand-to-hand. You, Gomez, all of you."

"I don't think that's sufficient."

"Victor - "

"With all due respect, Ms. Kramer, you're not facing up to the situation here," Baretto said stubbornly. "You've already lost two people. Three, if you count Traub."

"No, Victor. We've never lost anybody."

"You certainly lost Traub."

"We didn't lose Dr. Traub," she said. "Traub volunteered, and Traub was depressed."

"You assume he was depressed."

"We know he was, Victor. After his wife died, he was severely depressed, and suicidal. Even though he had passed his trip limit, he wanted to go back, to see if he could improve the technology. He had an idea that he could modify the machines to have fewer transcription errors. But apparently, his idea was wrong. That's why he ended up in the Arizona desert. Personally, I don't think he ever really intended to come back at all. I think it was suicide."

"And you lost Rob," Baretto said. "He wasn't any damn suicide."

Kramer sighed. Rob Deckard was one of the first of the observers to go back, almost two years earlier. And he was one of the first to show transcription errors. "That was much earlier in the project, Victor. The technology was less refined. And you know what happened. After he'd made several trips, Rob began to show minor effects. He insisted on continuing. But we didn't lose him."

"He went out, and he never came back," Baretto said. "That's the bottom line."

"Rob knew exactly what he was doing."

"And now the Professor."

"We haven't lost the Professor," she said. "He's still alive."

"You hope. And you don't know why he didn't come back in the first place."

"Victor - "

"I'm just saying," Baretto said, "in this case the logistics don't fit the mission profile. You're asking us to take an unnecessary risk."

"You don't have to go," Kramer said mildly.

"No, hell. I never said that."

"You don't have to."

"No. I'm going."

"Well, then, those are the rules. No modern technology goes into the world. Understood?"

"Understood."

"And none of this gets mentioned to the academics."

"No, no. Hell no. I'm professional."

"Okay," Kramer said.

She watched him leave. He was sulking, but he was going to go along with it. They always did, in the end. And the rule was important, she thought. Even though Doniger liked to give a little speech about how you couldn't change history, the fact was, nobody really knew  -  and nobody wanted to risk it. They didn't want modern weapons, or artifacts, or plastic to go back.

And they never had.

Stern sat with the others on hard-backed chairs in a room with maps. Susan Gomez, the woman who had just returned in the machine, spoke in a crisp, quick manner that Stern found rushed.

"We are going," she said, "to the Monastery of Sainte-M��re, on the Dordogne River, in southwestern France. We will arrive at 8:04 a.m. on the morning of Thursday, April 7, 1357  -  that's the day of the Professor's message. It's fortunate for us, because there's a tournament that day in Castelgard, and the spectacle will draw large crowds from the surrounding countryside, so we won't be noticed."

She tapped one map. "Just for orientation, the monastery is here. Castelgard is over here, across the river. And the fortress of La Roque is on the bluffs here, above the monastery. Questions so far?"

They shook their heads.

"All right. The situation in the area is a little unsettled. As you know, April of 1357 puts us roughly twenty years into the Hundred Years War. It's seven months after the English victory at Poitiers, where they took the king of France prisoner. The French king is now being held for ransom. And France, without a king, is in an uproar.

"Right now, Castelgard is in the hands of Sir Oliver de Vannes, a British knight born in France. Oliver has also taken over La Roque, where he is strengthening the castle's defenses. Sir Oliver's an unpleasant character, with a famously bad temper. They call him the 'Butcher of Crecy,' for his excesses in that battle."

"So Oliver is in control of both towns?" Marek said.

"At the moment, yes. However, a company of renegade knights, led by a defrocked priest called Arnaut de Cervole - "

"The Archpriest," Marek said.

"Yes, exactly, the Archpriest  -  is moving into the area, and will undoubtedly attempt to take the castles from Oliver. We believe the Archpriest is still several days away. But fighting may break out at any time, so we will work quickly."

She moved to another map, with a larger scale. It showed the monastery buildings.

"We arrive approximately here, at the edge of the For��t de Sainte-M��re. From our arrival point, we should be able to look right down on the monastery. Since the Professor's message came from the monastery, we will go directly there first. As you know, the monastery takes its main meal of the day at ten o'clock in the morning, and the Professor is likely to be present at that time. With luck, we'll find him there and bring him back."

Marek said, "How do you know all this? I thought nobody's ever gone into the world."

"That's correct. No one has. But observers close to the machines have still brought back enough that we know the background at this particular time. Any other questions?"

They shook their heads no.

"All right. It is very important we recover the Professor while he is still at the monastery. If he moves to either Castelgard or La Roque, it will be much more difficult. We have a tight mission profile. I expect to be on the ground between two and three hours. We will stay together at all times. If any of us is separated from the others, use your earpieces to get together again. We will find the Professor, and come right back. Okay?"

"Got it."

"You'll have two escorts, myself and Victor Baretto, over there in the corner. Say hello, Vic."

The second escort was a surly man who looked like an ex-marine  -  a tough and able man. Baretto's period clothes were more peasantlike, loose-fitting, made of a fabric like burlap. He gave a nod and a slight wave. He seemed to be in a bad mood.

"Okay?" Gomez said. "Other questions."

Chris said, "Professor Johnston has been there three days?"

"That's right."

"Who do the locals think he is?"

"We don't know," Gomez said. "We don't know why he left the machine in the first place. He must have had a reason. But since he is in the world, the simplest thing for him would be to pose as a clerk or scholar from London, on a pilgrimage to Santiago de Compostela in Spain. Sainte-M��re is on the pilgrimage route, and it is not unusual for pilgrims to break their trip, to stay a day or a week, especially if they strike up a friendship with the Abbot, who is quite a character. The Professor may have done that. Or he may not. We just don't know."

"But wait a minute," Chris Hughes said. "Won't his presence there change the local history? Won't he influence the outcome of events?"

"No. He won't."

"How do you know?"

"Because he can't."

"But what about the time paradoxes?"

"Time paradoxes?"

"That's right," Stern said. "You know, like going back in time and killing your grandfather, so that you can't be born and couldn't go back and kill your grandfather - "

"Oh, that." She shook her head impatiently. "There are no time paradoxes."

"What do you mean? Of course there are."

"No, there aren't," came a firm voice behind them. They turned; Doniger was there. "Time paradoxes do not occur."

"What do you mean?" Stern said. He was feeling put out that his question had been so roughly treated.

"The so-called time paradoxes," Doniger said, "do not really involve time. They involve ideas about history that are seductive but wrong. Seductive, because they flatter you into thinking you can have an impact on the course of events. And wrong, because of course, you can't."

"You can't have an impact on events?"

"No."

"Of course you can."

"No. You can't. It's easiest to see if you take a contemporary example. Say you go to a baseball game. The Yankees and the Mets  -  the Yankees are going to win, obviously. You want to change the outcome so that the Mets win. What can you do? You're just one person in a crowd. If you try to go to the dugout, you will be stopped. If you try to go onto the field, you will be hauled away. Most ordinary actions available to you will end in failure and will not alter the outcome of the game.

"Let's say you choose a more extreme action: you'll shoot the Yankee pitcher. But the minute you pull a gun, you are likely to be overpowered by nearby fans. Even if you get off a shot, you'll almost certainly miss. And even if you succeed in hitting the pitcher, what is the result? Another pitcher will take his place. And the Yankees will win the game.

"Let's say you choose an even more extreme action. You will release a nerve gas and kill everyone in the stadium. Once again, you're unlikely to succeed, for all the reasons you're unlikely to get a shot off. But even if you do manage to kill everybody, you still have not changed the outcome of the game. You may argue that you have pushed history in another direction  -  and perhaps so  -  but you haven't enabled the Mets to win the game. In reality, there is nothing you can do to make the Mets win. You remain what you always were: a spectator.

"And this same principle applies to the great majority of historical circumstances. A single person can do little to alter events in any meaningful way. Of course, great masses of people can 'change the course of history.' But one person? No."

"Maybe so," Stern said, "but I can kill my grandfather. And if he's dead then I couldn't be born, so I would not exist, and therefore I couldn't have shot him. And that's a paradox."

"Yes, it is  -  assuming you actually kill your grandfather. But that may prove difficult in practice. So many things go wrong in life. You may not meet up with him at the right time. You may be hit by a bus on your way. Or you may fall in love. You may be arrested by the police. You may kill him too late, after your parent has already been conceived. Or you may come face to face with him, and find you can't pull the trigger."

"But in theory . . ."

"When we are dealing with history, theories are worthless," Doniger said with a contemptuous wave. "A theory is only valuable if it has the ability to predict future outcomes. But history is the record of human action  -  and no theory can predict human action."

He rubbed his hands together.

"Now then. Shall we end all this speculation and be on our way?"

There were murmurs from the others.

Stern cleared his throat. "Actually," he said, "I don't think I'm going."

Marek had been expecting it. He'd watched Stern during the briefing, noticing the way he kept shifting in his chair, as if he couldn't get comfortable. Stern's anxiety had been steadily growing ever since the tour began.

Marek himself had no doubts about going. Since his youth, he had lived and breathed the medieval world, imagining himself in Warburg and Carcassonne, Avignon and Milan. He had joined the Welsh wars with Edward I. He had seen the burghers of Calais give up their city, and he had attended the Champagne Fairs. He had lived at the splendid courts of Eleanor of Aquitaine and the Duc de Berry. Marek was going to take this trip, no matter what. As for Stern -

"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."

"Okay. . . ."

"And, if we transmit through a wormhole, the person is always reconstituted at the other end. We can count on that happening, too."

There was a pause.

Stern frowned.

"Wait a minute," he said. "Are you saying that when you transmit, the person is being reconstituted by another universe?"

"In effect, yes. I mean, it has to be. We can't very well reconstitute them, because we're not there. We're in this universe."

"So you're not reconstituting. . . ."

"No."

"Because you don't know how," Stern said.

"Because we don't find it necessary," Gordon said. "Just as we don't find it necessary to glue plates to a table to make them stay put. They stay by themselves. We make use of a characteristic of the universe, gravity. And in this case, we are making use of a characteristic of the multiverse."

Stern frowned. He immediately distrusted the analogy; it was too glib, too easy.

"Look," Gordon said, "the whole point of quantum technology is that it overlaps universes. When a quantum computer calculates  -  when all thirty-two quantum states of the electron are being used  -  the computer is technically carrying out those calculations in other universes, right?"

"Yes, technically, but - "

"No. Not technically. Really."

There was a pause.

"It may be easier to understand," Gordon said, "by seeing it from the point of view of the other universe. That universe sees a person suddenly arrive. A person from another universe."

"Yes. . . ."

"And that's what happened. The person has come from another universe. Just not ours."

"Say again?"

"The person didn't come from our universe," Gordon said.

Stern blinked. "Then where?"

"They came from a universe that is almost identical to ours  -  identical in every respect  -  except that they know how to reconstitute it at the other end."

"You're joking."

"No."

"The Kate who lands there isn't the Kate who left here? She's a Kate from another universe?"

"Yes."

"So she's almost Kate? Sort of Kate? Semi-Kate?"

"No. She's Kate. As far as we have been able to tell with our testing, she is absolutely identical to our Kate. Because our universe and their universe are almost identical."

"But she's still not the Kate who left here."

"How could she be? She's been destroyed, and reconstructed."

"Do you feel any different when this happens?" Stern said.

"Only for a second or two," Gordon said.

Blackness.

Silence, and then in the distance, glaring white light.

Coming closer. Fast.

Chris shivered as a strong electric shock rippled through his body, and made his fingers twitch. For a moment, he suddenly felt his body, the way one feels clothes when you first put them on; he felt the encompassing flesh, felt the weight of it, the pull of gravity downward, the pressure of his body on the soles of his feet. Then a blinding headache, a single pulse, and then it was gone and he was surrounded by intense purple light. He winced, and blinked his eyes.

He was standing in sunlight. The air was cool and damp. Birds chirruped in the huge trees rising above him. Shafts of sunlight came down through the thick foliage, dappling the ground. He was standing in one beam. The machine stood beside a narrow muddy path that wound through a forest. Directly ahead, through a gap in the trees, he saw a medieval village.

First, a cluster of farm plots and huts, plumes of gray smoke rising from thatched roofs. Then a stone wall and the dark stone roofs of the town itself inside, and finally, in the distance, the castle with circular turrets.

He recognized it at once: the town and the fortress of Castelgard. And it was no longer a ruin. Its walls were complete.

He was here.

CASTELGARD

"Nothing in the world is as

certain as death."

JEAN FROISSART, 1359

37:00:00

Gomez hopped lightly out of the machine. Marek and Kate stepped slowly out of their cages, seemingly dazed as they looked around. Chris climbed out, too. His feet touched the mossy ground. It was springy underfoot.

Marek said, "Fantastic!" and immediately moved away from the machine, crossing the muddy path for a better look at the town. Kate followed behind him. She still seemed to be in shock.

But Chris wanted to stay close to the machine. He turned slowly, looking at the forest. It struck him as dark, dense, primeval. The trees, he noticed, were huge. Some of them had trunks so thick, you could hide three or four people behind them. They rose high into the sky, spreading a leafy canopy above them that darkened most of the ground below.

"Beautiful, isn't it?" Gomez said. She seemed to sense that he was uneasy.

"Yes, beautiful," he answered. But he didn't feel that way at all; something about this forest struck him as sinister. He turned round and round, trying to understand why he had the distinct feeling that something was wrong with what he was seeing  -  something was missing, or out of place. Finally, he said, "What's wrong?"

She laughed. "Oh, that," she said. "Listen."

Chris stood silently for a moment, listening. There was the chirp of birds, the soft rustle of a faint breeze in the trees. But other than that . . .

"I don't hear anything."

"That's right," Gomez said. "It upsets some people when they first arrive. There's no ambient noise here: no radio or TV, no airplanes, no machinery, no passing cars. In the twentieth century, we're so accustomed to hearing sound all the time, the silence feels creepy."

"I guess that's right." At least, that was exactly how he was feeling. He turned away from the trees and looked at the muddy path, a sunlit track through the forest. In many places, the mud was two feet deep, churned by many hooves.

This was a world of horses, he thought.

No machine sounds. Lots of hoofprints.

He took a deep breath, and let it out slowly. Even the air seemed different. Heady, bright-feeling, as if it had more oxygen in it.

He turned, and saw that the machine was gone. Gomez appeared unconcerned. "Where's the machine?" he said, trying not to sound worried.

"It drifted."

"It drifted?"

"When the machines are fully charged, they're a little unstable. They tend to slide off the present moment. So we can't see them."

"Where are they?" Chris said.

She shrugged. "We don't know, exactly. They must be in another universe. Wherever they are, they're fine. They always come back."

To demonstrate, she held up her ceramic marker and pressed the button with her thumbnail. In increasingly bright flashes of light, the machine returned: all four cages, standing exactly where they had been a few minutes before.

"Now, it'll stay here like this for maybe a minute, maybe two," Gomez said. "But eventually it will drift again. I just let them go. Gets 'em out of the way."

Chris nodded; she seemed to know what she was talking about. But the thought that the machines drifted made Chris vaguely uneasy; those machines were his ticket back home, and he didn't like to think that they behaved according to their own rules and could disappear at random. He thought, Would anybody fly on an airplane if the pilot said that it was "unstable"? He felt a coolness on his forehead, and he knew in a moment he would break out in a cold sweat.

To distract himself, Chris picked his way across the path, following the others, trying not to sink into the mud. On solid ground again, he pushed through thick ground cover, some kind of dense waist-high plant, like rhododendron. He glanced back at Gomez: "Anything to worry about in these woods?"

"Just vipers," she said. "They're usually in the lower branches of the trees. They fall down on your shoulders and bite you."

"Great," he said. "Are they poisonous?"

"Very."

"Fatal?"

"Don't worry, they're very rare," she said.

Chris decided not to ask any more questions. Anyway, by now he had reached a sunlit opening in the foliage. He looked down and saw the Dordogne River two hundred feet below him, twisting through farmland, and looking, he thought, not very different from the way he was used to seeing it.

But if the river was the same, everything else in this landscape was different. Castelgard was entirely intact, and so was its town. Beyond the walls were farming plots; some of the fields were being plowed now.

But his attention was drawn to the right, where he looked down on the great rectangular complex of the monastery  -  and the fortified mill bridge. His fortified bridge, he thought. The bridge he had been studying all summer -

And unfortunately, looking very different from the way he had reconstructed it in the computer.

Chris saw four water wheels, not three, churning in the current that ran beneath a bridge. And the bridge above was not a single unified structure. There seemed to be at least two independent structures, like little houses. The larger was made of stone and the other of wood, suggesting the structures had been built at different times. From the stone building, smoke belched in a continuous gray plume. So maybe they really were making steel there, he thought. If you had water-powered bellows, then you could have an actual blast furnace. That would explain the separate structures, too. Because mills that ground grain or corn never permitted any open fire or flame inside  -  not even a candle. That was why grinding mills operated only during daylight hours.

Absorbed in the details, he felt himself relax.

On the far side of the muddy path, Marek stared at the village of Castelgard with a slow sense of astonishment.

He was here.

He felt light-headed, almost giddy with excitement as he took in the details. In the fields below, peasants wore patched leggings and tunics in red and blue, orange and rose. The vivid colors stood out against the dark earth. Most of the fields were already planted, their furrows closed over. This was early April, so the spring planting of barley, peas, oats and beans  -  the so-called Lenten crops  -  would be nearly finished.

He watched a new field being plowed, the black iron blade hauled by two oxen. The plow itself turned the earth of the furrow neatly on both sides. He was pleased to see a low wooden guard mounted above the blade. That was a moldboard, and it was characteristic of this particular time.

Walking behind the plowman, a peasant sowed seed with rhythmic sweeps of his arm. The sack of seed hung from his shoulder. A short distance behind the sower, birds fluttered down to the furrow, eating the seed. But not for long. In a nearby field, Marek saw the harrower: a man riding a horse that dragged a wooden T-frame weighted down by a large rock. The harrower closed the furrows, protecting the seed.

Everything appeared to move in the same gentle, steady rhythm: the hand throwing seed, the plow turning the furrow, the harrow scraping the ground. And there was almost no sound in the still morning, just the hum of insects and the twitter of birds.

Beyond the fields, Marek saw the twenty-foot-high stone wall encircling the town of Castelgard. The stone was a dark, weathered gray. In one section, the wall was being repaired; the new stone was lighter in color, yellow-gray. Masons were hunched over, working quickly. Atop the wall itself, guards in chain mail strode back and forth, sometimes pausing to stare nervously into the distance.

And rising above everything, the castle itself, with its circular towers and black stone roofs. Flags fluttered from the turrets. All the flags showed the same emblem: a maroon-and-gray shield with a silver rose.

It gave the castle a festive appearance, and indeed, in a field just outside the town walls, a large wooden viewing stand, like bleachers, was being erected for the tournament. A crowd had already begun to gather. A few knights were there, horses tied beside the brightly colored striped tents that were pitched all around the tournament field itself. Pages and grooms threaded their way among the tents, carrying armor, and water for the horses.

Marek took it all in and gave a long, satisfied sigh.

Everything he saw was accurate, down to the smallest detail. Everything was real.

He was here.

Kate Erickson stared at Castelgard with a sense of puzzlement. Beside her, Marek was sighing like a lover, but she wasn't sure why. Of course, Castelgard was now a lively village, restored to its former glory, its houses and castle complete. But overall, the scene before her didn't look that different from any rural French landscape. Perhaps a little more backward than most, with horses and oxen instead of tractors. But otherwise . . . well, it just wasn't that different.

Architecturally, the biggest difference she saw in the scene before her and the present was that all the houses had lauzes roofs, made of stacked black stone. These stone roofs were incredibly heavy and required a great deal of internal bracing, which was why houses in the Perigord no longer used them, except in tourist areas. She was accustomed to seeing French houses with ocher roofs of curved Roman tile, or the flat tile of the French style.

Yet here, lauzes roofs were everywhere. There was no tile at all.

As she continued to look at the scene, she slowly noticed other details. For example, there were a lot of horses: really a lot, when you considered the horses in the fields, the horses at the tournament, the horses ridden on the dirt roads, and the horses put out to pasture. There must be a hundred horses in her view right now, she thought. She couldn't remember seeing so many horses at one time, even in her native Colorado. All kinds of horses, from beautiful sleek warhorses at the tournament to barnyard nags in the fields.

And while many of the people working in the fields were drably dressed, others wore colors so brilliant they almost reminded her of the Caribbean. These clothes were patched and patched again, but always in a contrasting color, so that the patchwork was visible even from a distance. It became a kind of design.

Then, too, she became aware of a clear demarcation between the relatively small areas of human habitation  -  towns and fields  -  and the surrounding forest, a dense, vast green carpet, stretching away in all directions. In this landscape, the forest predominated. She had the sense of encompassing wilderness, in which human beings were interlopers. And minor interlopers at that.

And as she looked again at the town of Castelgard itself, she sensed there was something odd that she couldn't put her finger on. Until she finally realized, there were no chimneys!

No chimneys anywhere.

The peasant houses simply had holes in the thatched roofs from which smoke issued. Within the town, the houses were similar, even though their roofs were stone: the smoke issued from a hole, or from a vent in a wall. The castle lacked chimneys, too.

She was looking at a time before chimneys appeared in this part of France. For some reason this trivial architectural detail made her shiver with a kind of horror. A world before chimneys. When had chimneys been invented, anyway? She couldn't remember exactly. Certainly by 1600, they were common. But that was a long time from now.

This "now," she reminded herself.

Behind her, she heard Gomez say, "What the hell do you think you're doing?"

Kate looked back and saw that the surly guy, Baretto, had arrived. His single cage was visible on the other side of the path, a few yards back in the woods.

"I'll do what I damn well want to do," he said to Gomez.

He had pulled up his burlap tunic, revealing a heavy leather belt with a holstered pistol and two black grenades. He was checking the pistol.

"If we're going into the world," Baretto said, "I'm going to be prepared."

"You're not bringing that stuff with you," Gomez said.

"The hell I'm not, sister."

"You're not. You know that's not allowed. Gordon would never permit modern weapons to be taken into the world."

"But Gordon's not here, is he?" Baretto said.

"Look, goddamn it," Gomez said, and she pulled out her white ceramic marker, waving it at Baretto.

It looked as if she was threatening to go back.

36:50:22

In the control room, one of the technicians at the monitors said, "We're getting field bucks."

"Oh, really? That's good news," Gordon said.

"Why?" Stern said.

"It means," Gordon said, "that someone is headed back in the next two hours. Undoubtedly your friends."

"So they will get the Professor and be back here within two hours?"

"Yes, that's exactly - " Gordon broke off, staring at the undulating image on the monitor. A little undulating surface, with a spike that stuck up. "Is that it?"

"Yes," the technician said.

"But the amplitude's much too large," Gordon said.

"Yes. And the interval's getting shorter. Fast."

"You mean someone is coming back now?"

"Yeah. Soon, it looks like."

Stern glanced at his watch. The team had been gone only a few minutes. They couldn't have recovered the Professor so quickly.

"What does that mean?" Stern asked him.

"I don't know," Gordon said. The truth was, he didn't like this development at all. "They must be having some sort of trouble."

"What kind of trouble?"

"This soon, it's probably mechanical. Maybe a transcription error."

Stern said, "What's a transcription error?"

The technician said, "I'm calculating an arrival in twenty minutes fifty-seven seconds." He was measuring the field strengths, and the pulse intervals.

"How many are coming back?" Gordon said. "All of them?"

"No," the technician said. "Just one."

36:49:19

Chris Hughes couldn't help it; he was anxious again. Despite the cool morning air, he was sweating, his skin cold, his heart pounding. Listening to Baretto and Gomez argue did nothing to increase his confidence.

He went back to the path, stepping around the pools of thick mud. Marek and Kate were coming back, too. They all stood a little apart from the argument.

"All right, all right, goddamn it," Baretto was saying. He took off his weapons and put them carefully on the floor of his cage. "All right. Does that satisfy you?"

Gomez was still speaking quietly, barely a whisper. Chris couldn't hear her.

"It's fine," Baretto said, almost snarling.

Gomez again spoke softly. Baretto was grinding his teeth. It was very uncomfortable to be standing there. Chris moved a few steps farther away, turning his back to the argument, waiting for it to be over.

He was surprised to see that the path sloped downward rather steeply, and he could see through a break in the trees to the flatland below. The monastery was there  -  a geometric arrangement of courtyards, covered passageways, and cloisters, all built of beige stone, surrounded by a high stone wall. It looked like a dense, compact little city. It was surprisingly close, perhaps a quarter of a mile. No more than that.

"Screw it, I'm walking," Kate said, and she started down the path. Marek and Chris looked at each other, then followed after her.

"You people stay in sight, damn it," Baretto called to them.

Gomez said, "I think we'd better go."

Baretto put a restraining hand on her arm. "Not until we get something cleared up," he said. "About how things are handled on this expedition."

"I think it's pretty well cleared up," Gomez said.

Baretto leaned close and said, "Because I didn't like the way you . . ." And the rest was too low to hear, just the furious hiss of his voice.

Chris was grateful to move around the curve in the path and leave them behind.

Kate started at a brisk walk, feeling the tension leave her body as she moved. The argument left her feeling cramped and edgy. A few paces behind her, she heard Chris and Marek talking. Chris was anxious, and Marek was trying to calm him down. She didn't want to hear it. She picked up the pace a little. After all, to be here, in these fantastic woods, surrounded by these huge trees . . .

After a minute or two, she had left Marek and Chris behind, but she knew they were near enough, and it was nice to be alone. The woods around her felt cool and relaxing. She listened to the chitter of birds and the sound of her own feet padding along on the path. Once she thought she heard something else, too. She slowed a bit to listen.

Yes, there was another sound: running feet. They seemed to be coming from farther down the path. She heard someone panting, gasping for breath.

And also a fainter sound, like the rumble of distant thunder. She was trying to place that rumble when a teenage boy burst around the corner, racing toward her.

The boy was wearing black hose, a bright green quilted jacket and a black cap. He was red-faced with exertion; he'd clearly been running for some time. He seemed startled to find her walking on the path. As he came toward her, he cried, "Aydethee amsel! Grassa due! Aydethee!"

An instant later, she heard his voice translated in her earpiece: "Hide, woman! For the sake of God! Hide!"

Hide from what? Kate wondered. These woods were deserted. What could he mean? Maybe she hadn't understood him right. Maybe the translator wasn't correct. As the boy passed her, he again cried, "Hide!" and shoved Kate hard, pushing her off the path and into the woods. She tripped on a gnarled root, tumbled into the undergrowth. She banged her head, felt sharp pain and a wave of dizziness. She was getting slowly to her feet when she realized what the rumbling sound was.

Horses.

Riding at full gallop toward her.

Chris saw the young boy running up the path, and almost immediately, he heard the sound of pursuing horses. The boy, finally out of breath, stopped for a moment beside them, doubled over, and finally managed to gasp, "Hide! Hide!" before he darted away into the woods.

Marek ignored the boy. He was looking down the path.

Chris frowned. "What is all that about - "

"Now," Marek said, and throwing an arm around Chris's shoulders, he pulled him bodily off the path and into the foliage.

"Jesus," Chris said, "would you mind telling me - "

"Shhh!" Marek put his hand over Chris's mouth. "Do you want to get us killed?"

No, Chris thought, he was clear on that: he did not want to get anybody killed. Charging up the hill toward them were six horsemen in full armor: steel helmets, chain mail and cloth surcoats of maroon and gray. The horses were draped in black cloth studded with silver. The effect was ominous. The lead rider, wearing a helmet with a black plume, pointed ahead and screamed, "Godin!"

Baretto and Gomez were still standing beside the path, just standing there, apparently in shock at what they saw galloping toward them. The black rider leaned over in the saddle and swung his broadsword in an arc at Gomez as he rode past her.

Chris saw Gomez's headless torso, spurting blood, as it toppled to the ground. Baretto, spattered with blood, swore loudly as he ran into the woods. More riders galloped up the hill. Now they were all shouting, "Godin! Godin!" One rider wheeled on his horse, drawing his bow.

The arrow struck Baretto's left shoulder as he ran, the steel point punching through the other side, the impact knocking him to his knees. Cursing, Baretto staggered to his feet again, and finally reached his machine.

He picked up his belt, yanked one of the grenades free, and turned to throw it. An arrow struck him full in the chest. Baretto looked surprised, coughed, and fell back, sprawled in a seated position against the bars. He made a feeble effort to pull the arrow out of his chest. The next arrow passed through his throat. The grenade dropped from his hand.

Back on the path, the horses reared and whinnied, their riders wheeling in circles, shouting and pointing.

There was a bright flash of light.

Chris looked back in time to see Baretto still seated, unmoving, as the machine flashed repeatedly, shrinking in size.

In moments, the machine was gone. The riders now had looks of fear on their faces. The black-plumed rider shouted something to the others, and as a group, they whipped their horses and raced on up the hill, out of sight.

As the black rider turned to go, his horse stumbled over Gomez's body. Cursing, the rider wheeled and reared his horse repeatedly, stomping the body again and again. Blood flew in the air; the horse's forelegs turned dark red. At last the black rider turned, and with a final curse, he galloped up the hill again to rejoin the others.

"Jesus." The suddenness of it, the casual violence -

Chris scrambled to his feet, ran back to the path.

Gomez's body lay in a muddy pool, crushed almost beyond recognition. But one hand was flung outward and lay open on the ground. And next to her hand lay the white ceramic marker.

It was cracked open, its electronic innards exposed.

Chris picked it up. The ceramic fell apart in his hands, bits of white and silver fluttering to the ground, falling into the muddy pool. And in that moment, their situation was clear to him.

Their guides were both dead.

One machine was gone.

Their return marker was shattered.

Which meant they were stuck in this place. Trapped here, without guides or assistance. And with no prospect of ever getting back.