On the radio, Kramer was saying, "And if you rebuild part of the town, then you could also rebuild part of the outer castle wall, where it is adjacent to the town. That section there." She was pointing to a low, ragged wall running northsouth across the site.

The Professor said, "Well, I suppose we could. . . ."

"And," Kramer continued, "you could extend the wall to the south, where it goes into the woods over there. You could clear the woods, and rebuild the tower."

Stern and Chris looked at each other.

"What's she talking about?" Stern said. "What tower?"

"Nobody's even surveyed the woods yet," Chris said. "We were going to clear it at the end of the summer, and then have it surveyed in the fall."

Over the radio, they heard the Professor say, "Your proposal is very interesting, Ms. Kramer. Let me discuss it with the others, and we'll meet again at lunch."

And then in the field below, Chris saw the Professor turn, look directly at them, and point a stabbing finger toward the woods.

Leaving the open field of ruins behind, they climbed a green embankment, and entered the woods. The trees were slender, but they grew close together, and beneath their canopy it was dark and cool. Chris Hughes followed the old outer castle wall as it diminished progressively from a waist-high wall to a low outcrop of stones, and then finally to nothing, disappearing beneath the underbrush.

From then on, he had to bend over, pushing aside the ferns and small plants with his hands in order to see the path of the wall.

The woods grew thicker around them. He felt a sense of peace here. He remembered that when he had first seen Castelgard, nearly the entire site had been within forest like this. The few standing walls were covered in moss and lichen, and seemed to emerge from the earth like organic forms. There had been a mystery to the site back then. But that had been lost once they cleared the land and began excavations.

Stern trailed along behind him. Stern didn't get out of the lab much, and he seemed to be enjoying it. "Why are all the trees so small?" he said.

"Because it's a new forest," Chris said. "Nearly all the forests in the Perigord are less than a hundred years old. All this land used to be cleared, for vineyards."

"And?"

Chris shrugged. "Disease. That blight, phylloxera, killed all the vines around the turn of the century. And the forest grew back." And he added, "The French wine industry almost vanished. They were saved by importing vines that were phylloxera-resistant, from California. Something they'd rather forget."

As he talked, he continued looking at the ground, finding a piece of stone here and there, just enough to enable him to follow the line of the old wall.

But suddenly, the wall was gone. He'd lost it entirely. Now he would have to double back, pick it up again.

"Damn."

"What?" Stern said.

"I can't find the wall. It was running right this way"  -  he pointed with the flat of his hand - " and now it's gone."

They were standing in an area of particularly thick undergrowth, high ferns intermixed with some kind of thorny vine that scratched at his bare legs. Stern was wearing trousers, and he walked forward, saying, "I don't know, Chris, it's got to be around here. . . ."

Chris knew he had to double back. He had just turned to retrace his steps when he heard Stern yell.

Chris looked back.

Stern was gone. Vanished.

Chris was standing alone in the woods.

"David?"

A groan. "Ah . . . damn."

"What happened?"

"I banged my knee. It hurts like a mother."

Chris couldn't see him anywhere. "Where are you?"

"In a hole," Stern said. "I fell. Be careful, if you come this way. In fact . . ." A grunt. Swearing. "Don't bother. I can stand. I'm okay. In fact  -  hey."

"What?"

"Wait a minute."

"What is it?"

"Just wait, okay?"

Chris saw the underbrush move, the ferns shifting back and forth, as Stern headed to the left. Then Stern spoke. His voice sounded odd. "Uh, Chris?"

"What is it?"

"It's a section of wall. Curved."

"What are you saying?"

"I think I'm standing at the bottom of what was once a round tower, Chris."

"No kidding," Chris said. He thought, How did Kramer know about that?

"Check the computer," the Professor said. "See if we have any helicopter survey scans  -  infrared or radar  -  that show a tower. It may already be recorded, and we just never paid attention to it."

"Late-afternoon infrared is your best bet," Stern said. He was sitting in a chair with an ice pack on his knee.

"Why late afternoon?"

"Because this limestone holds heat. That's why the cavemen liked it so much here. Even in winter, a cave in Perigord limestone was ten degrees warmer than the outside temperature."

"So in the afternoon . . ."

"The wall holds heat as the forest cools. And it'll show up on infrared."

"Even buried?"

Stern shrugged.

Chris sat at the computer console, started hitting keys. The computer made a soft beep. The image switched abruptly.

"Oops. We're in e-mail."

Chris clicked on the mailbox. There was just one message, and it took a long time to download. "What's this?"

"I bet it's that guy Wauneka," Stern said. "I told him to send a pretty big graphic. He probably didn't compress it."

Then the image popped up on the screen: a series of dots arranged in a geometric pattern. They all recognized it at once. It was unquestionably the Monastery of Sainte-M��re. Their own site.

In greater detail than their own survey.

Johnston peered at the image. He drummed his fingers on the tabletop. "It's odd," he said finally, "that Bellin and Kramer would both just happen to show up here on the same day."

The graduate students looked at each other. "What's odd about it?" Chris said.

"Bellin didn't ask to meet her. And he always wants to meet sources of funding."

Chris shrugged. "He seemed very busy."

"Yes. That's the way he seemed." He turned to Stern. "Anyway, print that out," he said. "We'll see what our architect has to say."

Katherine Erickson  -  ash-blond, blue-eyed, and darkly tanned  -  hung fifty feet in the air, her face just inches below the broken Gothic ceiling of the Castelgard chapel. She lay on her back in a harness and calmly jotted down notes about the construction above her.

Erickson was the newest graduate student on the site, having joined the project just a few months before. Originally, she had gone to Yale to study architecture, but found she disliked her chosen field, and transferred to the history department. There, Johnston had sought her out, convincing her to join him the way he had convinced all the others: "Why don't you put aside these old books and do some real history? Some hands-on history?"

So, hands-on it was  -  hanging way up here. Not that she minded: Kate had grown up in Colorado and was an avid climber. She spent every Sunday climbing the rock cliffs all around the Dordogne. There was rarely anyone else around, which was great: at home, you had to wait in line for the good pitches.

Using her pick, she chipped off a few flakes of mortar from different areas to take back for spectroscopic analysis. She dropped each into one of the rows of plastic containers, like film containers, that she wore over her shoulders and across her chest like a bandolier.

She was labeling the containers when she heard a voice say, "How do you get down from there? I want to show you something."

She glanced over her shoulder, saw Johnston on the floor below. "Easy," she said. Kate released her lines and slid smoothly to the ground, landing lightly. She brushed strands of blond hair back from her face. Kate Erickson was not a pretty girl  -  as her mother, a homecoming queen at UC, had so often told her  -  but she had a fresh, all-American quality that men found attractive.

"I think you'd climb anything," Johnston said.

She unclipped from the harness. "It's the only way to get this data."

"If you say so."

"Seriously," she said. "If you want an architectural history of this chapel, then I have to get up there and take mortar samples. Because that ceiling's been rebuilt many times  -  either because it was badly made and kept falling in, or because it was broken in warfare, from siege engines."

"Surely sieges," Johnston said.

"Well, I'm not so sure," Kate said. "The main castle structures  -  the great hall, the inner apartments  -  are solid, but several of the walls aren't well constructed. In some cases, it looks like walls were added to make secret passages. This castle's got several. There's even one that goes to the kitchen! Whoever made those changes must have been pretty paranoid. And maybe they did it too quickly." She wiped her hands on her shorts. "So. What've you got to show me?"

Johnston handed her a sheet of paper. It was a computer printout, a series of dots arranged in a regular, geometric pattern. "What's this?" she said.

"You tell me."

"It looks like Sainte-M��re."

"Is it?"

"I'd say so, yes. But the thing is . . ."

She walked out of the chapel, and looked down on the monastery excavation, about a mile away in the flats below. It was spread out almost as clearly as the drawing she held in her hand.

"Huh."

"What?"

"There's features on this drawing that we haven't uncovered yet," she said. "An apsidal chapel appended to the church, a second cloister in the northeast quadrant, and . . . this looks like a garden, inside the walls. . . . Where'd you get this picture, anyway?"

The restaurant in Marqueyssac stood on the edge of a plateau, with a view over the entire Dordogne valley. Kramer looked up from her table and was surprised to see the Professor arriving with both Marek and Chris. She frowned. She had expected to have a private lunch. She was at a table for two.

They all sat down together, Marek bringing two chairs from the next table. The Professor leaned forward and looked at her intently.

"Ms. Kramer," the Professor said, "how did you know where the rectory is?"

"The rectory?" She shrugged. "Well, I don't know. Wasn't it in the weekly progress report? No? Then maybe Dr. Marek mentioned it to me." She looked at the solemn faces staring at her. "Gentlemen, monasteries aren't exactly my specialty. I must have heard it somewhere."

"And the tower in the woods?"

"It must be in one of the surveys. Or the old photographs."

"We checked. It's not."

The Professor slid the drawing across the table to her. "And why does an ITC employee named Joseph Traub have a drawing of the monastery that is more complete than our own?"

"I don't know. . . . Where did you get this?"

"From a policeman in Gallup, New Mexico, who is asking some of the same questions I am."

She said nothing. She just stared at him.

"Ms. Kramer," he said finally. "I think you're holding out on us. I think you have been doing your own analysis behind our backs, and not sharing what you've found. And I think the reason is that you and Bellin have been negotiating to exploit the site in the event that I'm not cooperative. And the French government would be only too happy to throw Americans off their heritage site."

"Professor, that is absolutely not true. I can assure you - "

"No, Ms. Kramer. You can't." He looked at his watch. "What time does your plane go back to ITC?"

"Three o'clock."

"I'm ready to leave now."

He pushed his chair away from the table.

"But I'm going to New York."

"Then I think you'd better change your plans and go to New Mexico."

"You'll want to see Bob Doniger, and I don't know his schedule. . . ."

"Ms. Kramer." He leaned across the table. "Fix it."

As the Professor left, Marek said, "I pray God look with favor upon your journey and deliver you safe back." That was what he always said to departing friends. It had been a favorite phrase of the Count Geoffrey de la Tour, six hundred years before.

Some thought Marek carried his fascination with the past to the point of obsession. But in fact it was natural to him: even as a child, Marek had been strongly drawn to the medieval period, and in many ways he now seemed to inhabit it. In a restaurant, he once told a friend he would not grow a beard because it was not fashionable at the time. Astonished, the friend protested, "Of course it's fashionable, just look at all the beards around you." To which Marek replied, "No, no, I mean it is not fashionable in my time." By which he meant the thirteenth and fourteenth centuries.

Many medieval scholars could read old languages, but Marek could speak them: Middle English, Old French, Occitan, and Latin. He was expert in the fine points of period dress and manners. And with his size and athletic prowess, he set out to master the martial skills of the period. After all, he said, it was a time of perpetual war. Already he could ride the huge Percherons that had been used as destriers, or warhorses. And he was reasonably skilled at jousting, having spent hours practicing with the spinning tournament dummy called the quintain. Marek was so good with a longbow that he had begun to teach the skill to the others. And now he was learning to fight with a broadsword.

But his detailed knowledge of the past put him oddly out of touch with the present. The Professor's sudden departure left everyone on the project feeling bereft and uneasy; wild rumors flew, especially among the undergraduates: ITC was pulling its funding. ITC was turning the project into Medieval Land. ITC had killed somebody in the desert and was in trouble. Work stopped; people just stood around talking.

Marek finally decided he'd better hold a meeting to squelch the rumors, so in the early afternoon, he called everyone together under the big green tent outside the storehouse. Marek explained that a dispute had arisen between the Professor and ITC, and the Professor had gone back to ITC headquarters to clear it up. Marek said it was just a misunderstanding, which would be resolved in a few days. He said they would be in constant touch with the Professor, who had arranged to call them every twelve hours; and that he expected the Professor to return soon, and things to be normal once again.

It didn't help. The deep sense of unease remained. Several of the undergraduates suggested the afternoon was really too hot to work, and better suited for kayaking on the river; Marek, finally sensing the mood, said they might as well go.

One by one, the graduate students decided to take the rest of the day off, too. Kate appeared, with several pounds of metal clanking around her waist, and announced she was going to climb the cliff behind Gageac. She asked Chris if he wanted to come with her (to hold her ropes  -  she knew he would never climb), but he said he was going to the riding stables with Marek. Stern declared he was driving to Toulouse for dinner. Rick Chang headed off to Les Eyzies to visit a colleague at a Paleolithic site. Only Elsie Kastner, the graphologist, remained behind in the storehouse, patiently going over documents. Marek asked if she wanted to come with him. But she told him, "Don't be silly, Andre," and kept working.

The Equestrian Center outside Souillac was four miles away, and it was here that Marek trained twice a week. In the far corner of a little-used field, he had set up an odd T-shaped bar on a revolving stand. At one end of the T-bar was a padded square; at the other end, a leather teardrop that looked like a punching bag.

This was a quintain, a device so ancient that it had been drawn by monks at the edges of illuminated manuscripts a thousand years earlier. Indeed, it was from just such drawings that Marek had fashioned his own version.

Making the quintain had been simple enough; it was much more difficult to get a decent lance. This was the kind of problem Marek faced again and again in experimental history. Even the simplest and most common items from the past were impossible to reproduce in the modern world. Even when money was no object, thanks to the ITC research fund.

In medieval times, tournament lances were turned on wood lathes more than eleven feet long, which was the standard length of a jousting lance. But wood lathes of that size hardly existed anymore. After much searching, Marek located a specialty woodworking plant in northern Italy, near the Austrian border. They were able to turn out lances of pine to the dimensions he specified, but were astonished to hear he wanted an initial order of twenty. "Lances break," he told them. "I'll need a lot of them." To deal with splinters, he fitted a piece of screening to the faceplate of a football helmet. When he wore this helmet riding, he drew considerable attention. He looked like a demented beekeeper.

Eventually, Marek succumbed to modern technology, and he had his lances turned in aluminum, by a company that made baseball bats. The aluminum lances had better balance and felt more authentic to him, even though they were wrong for the period. And since splintering was no longer a problem, he could just wear a standard riding helmet.

Which was what he was wearing now.

Standing at the end of the field, he waved to Chris, who was over by the quintain. "Chris? Ready?"

Chris nodded and set the T-bar at right angles to Marek. He waved. Marek lowered his lance, and spurred his horse forward.

Training with the quintain was deceptively simple. The rider galloped toward the T-bar, attempting to strike the padded square with the tip of his lance. If he succeeded, he set the T-bar spinning, obliging him to spur his mount past before the leather bag swung around and hit him in the head. In the old days, Marek knew, the bag had been heavy enough to knock a young rider from his mount. But Marek made it just heavy enough to deliver a stinging rebuke.

On his first run, he hit the pad squarely, but he was not quick enough to avoid the bag, which boxed him on the left ear. He reined up, and trotted back. "Why don't you try one, Chris?"

"Maybe later," Chris said, repositioning the T-bar for the next run.

Once or twice in recent days, Marek had gotten Chris to try a run at the quintain. But he suspected that was only because of Chris's sudden recent interest in all aspects of horsemanship.

Marek turned his charger, reared, and charged again. When he first began, galloping full tilt toward a foot-square target had seemed absurdly difficult. Now he was getting the hang of it. He generally hit the target four out of five times.

The horse thundered ahead. He lowered his lance.

"Chris! Hallo!"

Chris turned, and waved to the girl riding up on horseback. At that moment, Marek's lance hit the pad, and the leather bag swung around, knocking Chris flat on his face.

Chris lay there, stunned, hearing peals of girlish laughter. But she quickly dismounted and helped him to his feet again. "Oh Chris, I'm sorry to laugh," she said in her elegant British accent. "It was all my fault, in any case. I oughtn't to have distracted you."

"I'm all right," he said, a little sulky. He brushed dirt from his chin and faced her, managing to smile.

As always, he was struck by her beauty, especially at this moment, her blond hair backlit in the afternoon sun so her perfect complexion seemed to glow, setting off her deep violet eyes. Sophie Rhys-Hampton was the most beautiful woman he had ever met in his life. And the most intelligent. And the most accomplished. And the most seductive.

"Oh, Chris, Chris," she said, brushing his face with cool fingertips. "I really do apologize. There, now. Any better?"

Sophie was a student at Cheltenham College; twenty years old, four years younger than he. Her father, Hugh Hampton, was a London barrister; he owned the farmhouse that the project rented for the summer. Sophie had come down to stay with friends in a farmhouse nearby. One day she had come round to collect something from her father's study. Chris had seen her, and promptly walked into a tree trunk.

Which seemed to have set the tone for their relationship, he thought ruefully. She looked at him now and said, "I'm flattered I have this effect on you, Chris. But I worry for your safety." She giggled, and kissed him lightly on the cheek. "I called you today."

"I know, I got tied up. We had a crisis."

"A crisis? What constitutes an archaeological crisis?"

"Oh, you know. Funding hassles."

"Oh yes. That ITC bunch. From New Mexico." She made it sound like the ends of the earth. "Do you know, they asked to buy my father's farm?"

"Did they?"

"They said they needed to rent it for so many years ahead, they might as well buy it. Of course he said no."

"Of course." He smiled at her. "Dinner?"

"Oh, Chris. I can't tonight. But we can ride tomorrow. Shall we?"

"Of course."

"In the morning? Ten o'clock?"

"All right," he said. "I'll see you at ten."

"I'm not interrupting your work?"

"You know you are."

"It's quite all right to do it another day."

"No, no," he said. "Ten o'clock tomorrow."

"Done," she said, with a dazzling smile.

In fact, Sophie Hampton was almost too pretty, her figure too perfect, her manner too charming to be quite real. Marek, for one, was put off by her.

But Chris was entranced.

After she rode away, Marek charged by again. This time Chris got out of the way of the swinging quintain. When Marek trotted back, he said, "You're being jerked around, my friend."

"Maybe," Chris said. But the truth was, he didn't care.

The next day found Marek at the monastery, helping Rick Chang with the excavations into the catacombs. They had been digging here for weeks now. And it was slow going, because they kept finding human remains. Whenever they came upon bones, they stopped digging with shovels, and switched to trowels and toothbrushes.

Rick Chang was the physical anthropologist on the team. He was trained to deal with human finds; he could look at a pea-sized piece of bone and tell you whether it came from the right wrist or the left, male or female, child or adult, ancient or contemporary.

But the human remains they were finding here were puzzling. For one thing, they were all male; and some of the long bones had evidence of battle injuries. Several of the skulls showed arrow wounds. That was how most soldiers had died in the fourteenth century, from arrows. But there was no record of any battle ever fought at the monastery. At least none that they knew of.

They had just found what looked like a bit of rusted helmet when Marek's cell phone rang. It was the Professor.

"How is it going?" Marek said.

"Fine, so far."

"Did you meet with Doniger?"

"Yes. This afternoon."

"And?"

"I don't know yet."

"They still want to go forward with the reconstruction?"

"Well, I'm not sure. Things are not quite what I expected here." The Professor seemed vague, preoccupied.

"How's that?"

"I can't discuss it over the line," the Professor said. "But I wanted to tell you: I won't be calling in the next twelve hours. Probably not for the next twenty-four hours."

"Uh-huh. Okay. Everything all right?"

"Everything is fine, Andre."

Marek wasn't so sure. "Do you need aspirin?" That was one of their established code phrases, a way to ask if something was wrong, in case the other person couldn't speak freely.

"No, no. Not at all."

"You sound a little detached."

"Surprised, I would say. But everything's fine. At least, I think it's fine." He paused, then, "And what about the site? What's going on with you?"

"I'm with Rick at the monastery now. We're digging in the catacombs of quadrant four. I think we'll be down later today, or tomorrow at the latest."

"Excellent. Keep up the good work, Andre. I'll talk to you in a day or two."

And he rang off.

Marek clipped the phone back on his belt and frowned. What the hell did all that mean?

The helicopter thumped by overhead, its sensor boxes hanging beneath. Stern had kept it for another day, to do morning and afternoon runs; he wanted to survey the features that Kramer had mentioned, to see exactly how much showed up in an instrument run.

Marek wondered how it was going, but to talk to him, he needed a radio. The nearest one was in the storehouse.

"Elsie," Marek said as he walked into the storehouse. "Where's the radio to talk to David?"

Of course, Elsie Kastner didn't answer him. She just continued to stare at the document in front of her. Elsie was a pretty, heavyset woman who was capable of intense concentration. She sat in this storehouse for hours, deciphering the handwriting on parchments. Her job required her to know not only the six principal languages of medieval Europe, but also long-forgotten local dialects, slang and abbreviations. Marek felt lucky to have her, even though she stayed aloof from the rest of the team. And she could be a little strange at times. He said, "Elsie?"

She looked up suddenly. "What? Oh, sorry, Andre. I'm just, uh, I mean a little . . ." She gestured to the parchment in front of her. "This is a bill from the monastery to a German count. For putting up his personal retinue for the night: twenty-nine people and thirty-five horses. That's what this count was taking with him through the countryside. But it's written in a combination of Latin and Occitan, and the handwriting is impossible."

Elsie picked up the parchment and carried it to the photography stand in the corner. A camera was mounted on a four-legged stand above the table, with strobe lights aiming from all sides. She set the parchment down, straightened it, arranged the bar code ID at the bottom, put a two-inch checkerboard ruler down for standardization, and snapped the picture.

"Elsie? Where's the radio to talk to David?"

"Oh, sorry. It's on the far table. It's the one with the adhesive strip that says DS."

Marek went over, pressed the button. "David? It's Andre."

"Hi, Andre." Marek could hardly hear him with the thumping of the helicopter.

"What've you found?"

"Zip. Nada. Absolutely nothing," Stern said. "We checked the monastery and we checked the forest. None of Kramer's landmarks show up: not on SLS, or on radar, infrared, or UV. I have no idea how they made these discoveries."

They were galloping full tilt along a grassy ridge overlooking the river. At least, Sophie was galloping; Chris bounced and jolted, hanging on for dear life. Ordinarily, she never galloped on their outings together, in deference to his lesser ability, but today she was shrieking with delight as she raced headlong across the fields.

Chris tried to stay with her, praying she would stop soon, and finally she did, reining up her snorting and sweaty black stallion, patting it on the neck, waiting for him to catch up.

"Wasn't that exciting?" she said.

"It was," he said, gasping for breath. "It certainly was that."

"You did very well, Chris, I must say. Your seat is improving."

All he could do was nod. His seat was painful after all the bouncing, and his thighs ached from squeezing so hard.

"It's beautiful here," she said, pointing to the river, the dark castles on the far cliffs. "Isn't it glorious?"

And then she glanced at her watch, which annoyed him. But walking turned out to be surprisingly pleasant. She rode very close to him, the horses almost touching, and she leaned over to whisper in his ear; once she threw her arm around his shoulder and kissed him on the mouth, before glancing away, apparently embarrassed by her moment of boldness.

From their present position, they overlooked the entire site: the ruins of Castelgard, the monastery, and on the far hill, La Roque. Clouds raced overhead, moving shadows across the landscape. The air was warm and soft, and it was quiet, except for the distant rumble of an automobile.

"Oh, Chris," she said, and kissed him again. When they broke, she looked away in the distance, and suddenly waved.

A yellow convertible was winding up the road toward them. It was some sort of racing car, low-slung, its engine growling. A short distance away, it stopped, and the driver stood up behind the wheel, sitting on the back of the seat.

"Nigel!" she cried happily.

The man in the car waved back lazily, his hand tracing a slow arc.

"Oh Chris, would you be a dear?" Sophie handed Chris the reins of her horse, dismounted, and ran down the hill to the car, where she embraced the driver. The two of them got in the car. As they drove off, she looked back at Chris and blew him a kiss.

The restored medieval town of Sarlat was particularly charming at night, when its cramped buildings and narrow alleys were lit softly by gas lamps. On the rue Tourny, Marek and the graduate students sat in an outdoor restaurant under white umbrellas, drinking the dark red wine of Cahors into the night.

Usually, Chris Hughes enjoyed these evenings, but tonight nothing seemed right to him. The evening was too warm; his metal chair uncomfortable. He had ordered his favorite dish, pintade aux c��pes, but the guinea hen tasted dry, and the mushrooms were bland. Even the conversation irritated him: usually, the graduate students talked over the day's work, but tonight their young architect, Kate Erickson, had met some friends from New York, two American couples in their late twenties  -  stock traders with their girlfriends. He disliked them almost immediately.

The men were constantly getting up from the table to talk on cell phones. The women were both publicists in the same PR firm; they had just finished a very big party for Martha Stewart's new book. The group's bustling sense of their own self-importance quickly got on Chris's nerves; and, like many successful business people, they tended to treat academics as if they were slightly retarded, unable to function in the real world, to play the real games. Or perhaps, he thought, they just found it inexplicable that anyone would choose an occupation that wouldn't make them a millionaire by age twenty-four.

Yet he had to admit they were perfectly pleasant; they were drinking a lot of wine, and asking a lot of questions about the project. Unfortunately, they were the usual questions, the ones tourists always asked: What's so special about that place? How do you know where to dig? How do you know what to look for? How deep do you dig and how do you know when to stop?

"Why are you working there? What's so special about that place, anyway?" one of the women asked.

"The site is very typical for the period," Kate said, "with two opposing castles. But what makes it a real find is that it has been a neglected site, never previously excavated."

"That's good? That it was neglected?" The woman was frowning; she came from a world where neglect was bad.

"It's very desirable," Marek said. "In our work, the real opportunities arise only when the world passes an area by. Like Sarlat, for instance. This town."

"It's very sweet here," one of the women said. The men stepped away to talk on their phones.

"But the point," Kate said, "is that it's an accident that this old town exists at all. Originally, Sarlat was a pilgrimage town that grew up around a monastery with relics; eventually it got so big that the monastery left, looking for peace and quiet elsewhere. Sarlat continued as a prosperous market center for the Dordogne region. But its importance diminished steadily over the years, and in the twentieth century, the world passed Sarlat by. It was so unimportant and poor that the town didn't have the money to rebuild its old sections. The old buildings just remained standing, with no modern plumbing and electricity. A lot of them were abandoned."

Kate explained that in the 1950s, the city was finally going to tear the old quarter down and put up modern housing. "Andre Malraux stopped it. He convinced the French government to put aside funds for restoration. People thought he was crazy. Now, Sarlat's the most accurate medieval town in France, and one of the biggest tourist attractions in the country."

"It's nice," the woman said, vaguely. Suddenly, both men returned to the table together, sat down, and put their phones in their pockets with an air of finality.

"What happened?" Kate said.

"Market closed," one explained. "So. You were saying about Castelgard. What's so special about it?"

Marek said, "We were discussing the fact that it's never been excavated before. But it's also important to us because Castelgard is a typical fourteenth-century walled town. The town is older than that, but between 1300 and 1400 most of its structures were built, or modified, for greater defense: thicker walls, concentric walls, more complicated moats and gates."

"This is when? The Dark Ages?" one of the men said, pouring wine.

"No," Marek said. "Technically, it's the High Middle Ages."

"Not as high as I'm going to be," the man said. "So what comes before that, the Low Middle Ages?"

"That's right," Marek said.

"Hey," the man said, raising his wineglass. "Right the first time!"

Starting around 40 B.C., Europe had been ruled by Rome. The region of France where they now were, Aquitaine, was originally the Roman colony of Aquitania. All across Europe, the Romans built roads, supervised trade, and maintained law and order. Europe prospered.

Then, around A.D. 400, Rome began to withdraw its soldiers and abandon its garrisons. After the empire collapsed, Europe sank into lawlessness, which lasted for the next five hundred years. Population fell, trade died, towns shrank. The countryside was invaded by barbarian hordes: Goths and Vandals, Huns and Vikings. That dark period was the Low Middle Ages.

"But toward the last millennium  -  I mean A.D. 1000  -  things began to get better," Marek said. "A new organization coalesced that we call the feudal system  -  although back then, people never used that word."

Under feudalism, powerful lords provided local order. The new system worked. Agriculture improved. Trade and cities flourished. By A.D. 1200, Europe was thriving again, with a larger population than it had had during the Roman Empire. "So the year 1200 is the beginning of the High Middle Ages  -  a time of growth, when culture flourished."

The Americans were skeptical. "If it was so great, why was everybody building more defenses?"

"Because of the Hundred Years War," Marek said, "which was fought between England and France."

"What was it, a religious war?"

"No," Marek said. "Religion had nothing to do with it. Everyone at the time was Catholic."

"Really? What about the Protestants?"

"There were no Protestants."

"Where were they?"

Marek said, "They hadn't invented themselves yet."

"Really? Then what was the war about?"

"Sovereignty," Marek said. "It was about the fact that England owned a large part of France."

One of the men frowned skeptically. "What are you telling me? England used to own France?"

Marek sighed.

He had a term for people like this: temporal provincials  -  people who were ignorant of the past, and proud of it.

Temporal provincials were convinced that the present was the only time that mattered, and that anything that had occurred earlier could be safely ignored. The modern world was compelling and new, and the past had no bearing on it. Studying history was as pointless as learning Morse code, or how to drive a horse-drawn wagon. And the medieval period  -  all those knights in clanking armor and ladies in gowns and pointy hats  -  was so obviously irrelevant as to be beneath consideration.

Yet the truth was that the modern world was invented in the Middle Ages. Everything from the legal system, to nation-states, to reliance on technology, to the concept of romantic love had first been established in medieval times. These stockbrokers owed the very notion of a market economy to the Middle Ages. And if they didn't know that, then they didn't know the basic facts of who they were. Why they did what they did. Where they had come from.

Professor Johnston often said that if you didn't know history, you didn't know anything. You were a leaf that didn't know it was part of a tree.

The stock trader continued, pushing in the stubborn way that some people did when confronted with their own ignorance: "Really? England used to own part of France? That doesn't make any sense. The English and French have always hated each other."

"Not always," Marek said. "This was six hundred years ago. It was a completely different world. The English and French were much closer then. Ever since soldiers from Normandy conquered England in 1066, all the English nobility were basically French. They spoke French, ate French food, followed French fashions. It wasn't surprising they owned French territory. Here in the south, they had ruled Aquitaine for more than a century."

"So? What was the war about? The French decided they wanted it all for themselves?"

"More or less, yes."

"Figures," the man said, with a knowing nod.

Marek lectured on. Chris passed the time trying to catch Kate's eye. Here in candlelight, the angles of her face, which looked hard, even tough, in sunlight, were softened. He found her unexpectedly attractive.

But she did not return his look. Her attention was focused on her stockbroker friends. Typical, Chris thought. No matter what they said, women were only attracted to men with power and money. Even manic and sleazy men like these two.

He found himself studying their watches. Both men wore big, heavy Rolexes, but the metal watchbands were fitted loosely, so the watches flopped and dangled down their wrists, like a woman's bracelet. It was a sign of indifference and wealth, a casual sloppiness that suggested they were permanently on vacation. It annoyed him.

When one of the men began to play with his watch, flipping it around on his wrist, Chris finally could stand it no longer. Abruptly, he got up from the table. He mumbled some excuse about having to check on his analyses back at the site, and headed down the rue Tourny toward the parking lot at the edge of the old quarter.

All along the street, it seemed to him that he saw only lovers, couples strolling arm in arm, the woman with her head on the man's shoulder. They were at ease with each other, having no need to speak, just enjoying the surroundings. Each one he passed made him more irritable, and made him walk faster.

It was a relief when he finally got to his car, and drove home.

Nigel!

What kind of an idiot had a name like Nigel?

The following morning, Kate was again hanging in the Castelgard chapel when her radio crackled and she heard the cry "Hot tamales! Hot tamales! Grid four. Come and get it! Lunch is served."

That was the team's signal that a new discovery had been made. They used code words for all their important transmissions, because they knew local officials sometimes monitored them. At other sites, the government had occasionally sent agents in to confiscate discoveries at the moment they were first found, before the researchers had a chance to document and evaluate them. Although the French government had an enlightened approach to antiquities  -  in many ways better than Americans  -  individual field inspectors were notoriously inconsistent. And, of course, there was often some feeling about foreigners appropriating the noble history of France.

Grid four, she knew, was over at the monastery. She debated whether to stay in the chapel or to go all the way over there, but finally she decided to go. The truth was that much of their daily work was dull and uneventful. They all needed the renewed enthusiasm that came with the excitement of discoveries.

She walked through the ruins of Castelgard town. Unlike many others, Kate could rebuild the ruins in her mind, and see the town whole. She liked Castelgard; this was a no-nonsense town, conceived and built in time of war. It had all the straightforward authenticity that she had found missing in architecture school.

She felt the hot sun on her neck and her legs and thought for the hundredth time how glad she was to be in France, and not sitting in New Haven at her cramped little workspace on the sixth floor of the A & A Building, with big picture windows overlooking fake-colonial Davenport College and fake-Gothic Payne Whitney Gym. Kate had found architecture school depressing, she had found the Arts and Architecture Building very depressing, and she had never regretted her switch to history.

Certainly, you couldn't argue with a summer in southern France. She fitted into the team here at the Dordogne quite well. So far it had been a pleasant summer.

Of course, there had been some men to fend off. Marek had made a pass early on, and then Rick Chang, and soon she would have to deal with Chris Hughes as well. Chris took the British girl's rejection hard  -  he was apparently the only one in the Perigord who hadn't seen it coming  -  and now he was behaving like a wounded puppy. He'd been staring at her last night, during dinner. Men didn't seem to realize that rebound behavior was slightly insulting.

Lost in her thoughts, she walked down to the river, where the team kept the little rowboat that they used to ferry across.

And waiting there, smiling at her, was Chris Hughes.

"I'll row," he offered as they climbed into the boat. She let him. He began to pull across the river in easy strokes. She said nothing, just closed her eyes, turned her face up to the sun. It felt warm, relaxing.

"Beautiful day," she heard him say.

"Yes, beautiful."

"You know, Kate," he began, "I really enjoyed dinner last night. I was thinking maybe - "

"That's very flattering, Chris," she said. "But I have to be honest with you."

"Really? About what?"

"I've just broken up with someone."

"Oh. Uh-huh. . . ."

"And I want to take some time off."

"Oh," he said. "Sure. I understand. But maybe we could still - "

She gave him her nicest smile. "I don't think so," she said.

"Oh. Okay." She saw that he was starting to pout. Then he said, "You know, you're right. I really think it's best that we just stay colleagues."

"Colleagues," she said, shaking hands with him.

The boat touched the far shore.

At the monastery, a large crowd was standing around at the top of grid four, looking down into the excavation pit.

The excavation was a precise square, twenty feet on a side, going down to a depth of ten feet. On the north and east sides, the excavators had uncovered flat sides of stone arches, which indicated the dig was now within the catacomb structure, beneath the original monastery. The arches themselves were filled in with solid earth. Last week, they had dug a trench through the north arch, but it seemed to lead nowhere. Shored up with timbers, it was now ignored.

Now all the excitement was directed to the east arch, where in recent days they had dug another trench under the arch. Work had been slow because they kept finding human remains, which Rick Chang identified as the bodies of soldiers.

Looking down, Kate saw that the walls of the trench had collapsed on both sides, the earth falling inward, covering the trench itself. There was now a great mound of earth, like a landslide, blocking further progress, and as the earth collapsed, brownish skulls and long bones  -  lots of them  -  had tumbled out.

She saw Rick Chang down there, and Marek, and Elsie, who had left her lair to come out here. Elsie had her digital camera on a tripod, snapping off shots. These would later be stitched together in the computer to make 360-degree panoramas. They would be taken at hourly intervals, to record every phase of the excavation.

Marek looked up and saw Kate on the rim. "Hey," he said. "I've been looking for you. Get down here."

She scrambled down the ladder to the earthen floor of the pit. In the hot midafternoon sun, she smelled dirt, and the faint odor of organic decay. One of the skulls broke free and rolled to the ground at her feet. But she didn't touch it; she knew the remains should stay as they were until Chang removed them.

"This may be the catacombs," Kate said, "but these bones weren't stored. Was there ever a battle here?"

Marek shrugged. "There were battles everywhere. I'm more interested in that." He pointed ahead to the arch, which was without decoration, rounded and slightly flattened.

Kate said, "Cistercian, could even be twelfth century. . . ."

"Okay, sure. But what about that?" Directly beneath the central curve of the arch, the collapse of the trench had left a black opening about three feet wide.

She said, "What are you thinking?"

"I'm thinking we better get in there. Right away."

"Why?" she said. "What's the hurry?"

Chang said to her, "It looks like there's space beyond the opening. A room, maybe several rooms."

"So?"

"Now it's exposed to the air. For the first time in maybe six hundred years."

Marek said, "And air has oxygen."

"You think there's artifacts in there?"

"I don't know what's in there," Marek said. "But you could have considerable damage within a few hours." He turned to Chang. "Have we got a snake?"

"No, it's in Toulouse, being repaired." The snake was a fiber optic cable that could be hooked to a camera. They used it to view otherwise inaccessible spaces.

Kate said, "Why don't you just pump the room full of nitrogen?" Nitrogen was an inert gas, heavier than air. If they pumped it through the opening, it would fill the space up, like water. And protect any artifacts from the corrosive effects of oxygen.

"I would," Marek said, "if I had enough gas. The biggest cylinder we've got is fifty liters."

That wasn't enough.

She pointed to the skulls. "I know, but if you do anything now, you'll disturb - "

"I wouldn't worry about these skeletons," Chang said. "They've already been moved out of position. And they look like they were mass-graved, after a battle. But there isn't that much we can learn from them." He turned and looked up. "Chris, who's got the reflector?"

Up above, Chris said, "Not me. I think they were last used here."

One of the students said, "No, it's over by grid three."

"Let's get it. Elsie, are you about finished with your pictures?"

"Pushy, pushy."

"Are you, or not?"

"One minute more."

Chang was calling to the students above, telling them to bring the reflectors. Four of them ran off excitedly.

Marek was saying to the others, "Okay, you people, I want flashlights, I want excavation packs, portable oxygen, filter headsets, lead lines, the works  -  now."

Through the excitement, Kate continued to eye the opening beneath the arch. The arch itself looked weak to her, the stones held loosely together. Normally, an arch kept its shape by the weight of the walls pressing in on the center stone, the keystone of the arch. But here, the whole upper curve above the opening could just collapse. The landslide of earth underneath the opening was loose. She watched pebbles break free and trickle down here and there. It didn't look good to her.

"Andre, I don't think it's safe to climb over that. . . ."

"Who's talking about climbing over? We'll lower you from above."

"Me?"

"Yeah. You hang from above the arch, and then go inside." She must have looked stricken, because he grinned. "Don't worry, I'll go with you."

"You realize, if we're wrong . . ." She was thinking, We could be buried alive.

"What's this?" Marek said. "Losing your nerve?"

That was all he had to say.

Ten minutes later, she was hanging in midair by the edge of the exposed arch. She wore the excavation backpack, which was fitted with an oxygen bottle on the back and had two flashlights dangling like hand grenades from the waist straps. She had her filter headset pushed up on her forehead. Wires ran from the radio to a battery in her pocket. With so much equipment she felt clunky, uncomfortable. Marek stood above her, holding her safety line. And down in the pit, Rick and his students were watching her tensely.

She looked up at Marek. "Give me five." He released five feet of line, and she slid down until she was lightly touching the dirt mound. Little rivulets of earth trickled away beneath her feet. She eased herself forward.

"Three more."

She dropped to hands and knees, giving the mound her full weight. It held. But she looked up at the arch uneasily. The keystone was crumbling at the edges.

"Everything all right?" Marek called.

"Okay," she said. "I'll go in now."

She crawled back toward the gaping hole at the arch. She looked up at Marek, unhooked the flashlight. "I don't know if you can do this, Andre. The dirt may not support your weight."

"Very funny. You don't do this alone, Kate."

"Well, at least let me get in there first."

She flicked on her light, turned on her radio, pulled down her headset so she was breathing through filters, and crawled through the hole, into the blackness beyond.

The air was surprisingly cool. The yellow beam of her flashlight played on bare stone walls, a stone floor. Chang was right: this was open space beneath the monastery. And it seemed to continue for some distance, before dirt and collapsed rubble blocked the far passage. Somehow this chamber had not been filled with dirt like the others. She shone her light up at the roof, trying to see its condition. She couldn't really tell. Not great.

She crept forward on hands and knees, then began to descend, sliding a little, down the dirt toward the ground. Moments later, she was standing inside the catacombs.

"I'm here."

It was dark around her, and the air felt wet. There was a dank odor that was unpleasant, even through the filters. The filters took out bacteria and viruses. At most excavation sites, no one bothered with masks, but they were required here, because plague had come several times in the fourteenth century, killing a third of the population. Although one form of the epidemic was originally transmitted by infected rats, another form was transmitted through the air, through coughs and sneezes, and so anybody who went into an old, sealed space had to worry about -

She heard a clattering behind her. She saw Marek coming through the hole above. He began to slide, so he jumped to the ground. In the silence afterward, they heard the soft sounds of pebbles and earth, trickling down the mound.

"You realize," she said, "we could be buried alive in here."

"Always look on the bright side," Marek said. He moved forward, holding a big fluorescent light with reflectors. It illuminated a whole section of the room. Now that they could see clearly, the room appeared disappointingly bare. To the left was the stone sarcophagus of a knight; he was carved in relief on the lid, which had been removed. When they looked inside the sarcophagus, it was empty. Then there was a rough wooden table leaning against a wall. It was bare. An open corridor going down to their left, ending in a stone staircase, which led upward until it disappeared in a mound of dirt. More mounds of earth in this chamber, over to the right, blocking another passageway, another arch.

Marek sighed. "All this excitement . . . for nothing."

But Kate was still worried about the earth breaking free and coming into the room. It made her look closely at the earth mounds to the right.

And that was why she saw it.

"Andre," she said. "Come here."

It was an earth-colored protrusion, brown against the brown of the mound, but the surface had a faint sheen. She brushed it with her hand. It was oilcloth. She exposed a sharp corner. Oilcloth, wrapping something.

Marek looked over her shoulder. "Very good, very good."

"Did they have oilcloth then?"

"Oh yes. Oilcloth is a Viking invention, perhaps ninth century. Quite common in Europe by our period. Although I don't think we have found anything else in the monastery that's wrapped in oilcloth."

He helped her dig. They proceeded cautiously, not wanting the mound to come down on them, but soon they had it exposed. It was a rectangle roughly two feet square, wrapped with oil-soaked string.

"I am guessing it's documents," Marek said. His fingers were twitching in the fluorescent light, he wanted to open it so badly, but he restrained himself. "We'll take it back with us."

He slipped it under his arm and headed back toward the entrance. She gave one last look at the earth mound, wondering if she had missed something. But she hadn't. She swung her light away and -