Stern said, "I agree. This has to be a joke."

"But we're not going to know for sure without a carbon date," Marek said. Carbon-14 would enable them to date both ink and parchment within about fifty years. That would be good enough to settle the question of forgery.

"I'd also like to do thermoluminescence, and maybe a laser activation while we're at it," Stern said.

"You can't do that here."

"No, I'll take it over to Les Eyzies." Les Eyzies, the town in the next valley that was the center of prehistoric studies in southern France, had a well-equipped lab that did carbon-14 and potassium-argon dating, as well as neutron activation and other difficult tests. The field results weren't as accurate as the labs in Paris or Toulouse, but scientists could get an answer in a few hours.

"Any chance you can run it tonight?" Marek said.

"I'll try."

Chris came back to join the group; he had been telephoning the Professor on a cell phone. "Nothing," he said. "I just got his voicemail."

"All right," Marek said. "There's nothing more we can do right now. I assume this message is a bizarre joke. I can't imagine who played it on us - but somebody did. Tomorrow we'll run carbon and date the message. I have no doubt it will prove to be recent. And with all due respect to Elsie, it's probably a forgery."

Elsie started to sputter.

"But in any case," Marek continued, "the Professor is due to call in tomorrow, and we'll ask him. In the meantime, I suggest we all go to bed and get a good night's rest."

In the farmhouse, Marek closed the door softly behind him before turning on the lights. Then he looked around.

The room was immaculate, as he would have expected. It had the tidiness of a monk's cell. Beside the bed stood five or six research papers, neatly stacked. On a desk to the right, more research papers sat beside a closed laptop computer. The desk had a drawer, which he opened and rummaged through quickly.

But he didn't find what he was looking for.

He went next to the armoire. The Professor's clothes were neatly arranged inside, with space between each hanging garment. Marek went from one to the next, patting the pockets, but he still did not find it. Perhaps it wasn't here, he thought. Perhaps he had taken it with him to New Mexico.

There was a bureau opposite the door. He opened the top drawer: coins in a small shallow dish, American dollar bills wrapped in a rubber band, and a few personal objects, including a knife, a pen and a spare watch - nothing out of the ordinary.

Then he saw a plastic case, tucked over to one side.

He brought the case out, opened it up. The case contained eyeglasses. He set the glasses out on the counter.

The lenses were bifocals, oval in shape.

He reached into his shirt pocket and brought out a plastic bag. He heard a creak behind him, and turned to see Kate Erickson coming in through the door.

"Going through his underwear?" she said, raising her eyebrows. "I saw the light under the door. So I had a look."

"Without knocking?" Marek said.

"What are you doing in here?" she said. Then she saw the plastic. "Is that what I think it is?"

"Yes."

Marek took the single bifocal lens out of the plastic bag, holding it with a pair of tweezers, and placed it on top of the bureau, beside the Professor's eyeglasses.

"Not identical," she said. "But I'd say the lens is his."

"So would I."

But isn't that what you always thought? I mean, he's the only one on the site who wears bifocals. The contamination has to be from his eyeglasses."

"But there isn't any contamination," Marek said. "This lens is old."

"What?"

"David says that white edge is bacterial growth. This lens is not modern, Kate. It's old."

She looked closely. "It can't be," she said. "Look at the way the lenses are cut. It's the same in the Professor's glasses and this lens. It must be modern."

"I know, but David insists it's old."

"How old?"

"He can't tell."

"He can't date it?"

Marek shook his head. "Not enough organic material."

"So in that case," she said, "you came to his room because…" She paused, staring at the eyeglasses, then at him. She frowned. "I thought you said that signature was a forgery, Andre."

"I did, yes."

"But you also asked if David could do the carbon test tonight, didn't you."

"Yes…"

"And then you came here, with the glass, because you're worried…" She shook her head as if to clear it. "About what? What do you think is going on?"

Marek looked at her. "I have absolutely no idea. Nothing makes sense."

"But you're worried."

"Yes," Marek said. "I'm worried."

The following day dawned bright and hot, a glaring sun beneath a cloudless sky. The Professor didn't call in the morning. Marek called him twice, but always got his voicemail: "Leave me a message, and I'll call you back."

Nor was there any word from Stern. When they called the lab at Les Eyzies they were told he was busy. A frustrated technician said, "He is repeating the tests again! Three times now!"

Why? Marek wondered. He considered going over to Les Eyzies to see for himself - it was just a short drive - but decided to stay at the storehouse in case the Professor called.

He never called.

In the middle of the morning, Elsie said, "Huh."

"What?"

She was looking at another piece of parchment. "This was the document on the stack right before the Professor's," she said.

Marek came over. "What about it?"

"It looks like there are ink spots from the Professor's pen. See, here, and here?"

Marek shrugged. "He was probably looking at this right before he wrote his note."

"But they're in the margin," she said, "almost like a notation."

"Notation to what?" he said. "What's the document about?"

"It's a piece of natural history," she said. "A description of an underground river by one of the monks. Says you have to be cautious at various points, marked off in paces, so on and so forth."

"An underground river… ." Marek wasn't interested. The monks were the scholars of the region, and they often wrote little essays on local geography, or carpentry, the proper time to prune orchard trees, how best to store grain in winter, and so on. They were curiosities, and often wrong.

" `Marcellus has the key,' " she said, reading the text. "Wonder what that means. It's right where the Professor Professor put his marks. Then… something about… giant feet… no… the giant's feet?… The feet of the giant?… And it says vivix, which is Latin for… let me see… That's a new one.

…"

She consulted a dictionary.

Restless, Marek went outside and paced up and down. He was edgy, nervous.

"That's odd," she said, "there is no word vivix. At least not in this dictionary." She made a note, in her methodical way.

Marek sighed.

The hours crawled by.

The Professor never called.

Finally it was three o'clock; the students were wandering up to the big tent for their afternoon break. Marek stood in the door and watched them. They seemed carefree, laughing, punching each other, making jokes.

The phone rang. He immediately turned back. Elsie picked it up. He heard her say, "Yes, he's here with me right now…"

He hurried into her room. "The Professor?"

She was shaking her head. "No. It's someone from ITC." And she handed him the phone.

"This is Andre Marek speaking," he said.

"Oh yes. Please hold, Mr. Marek. I know Mr. Doniger is eager to speak to you."

"He is?"

"Yes. We've been trying to reach you for several hours. Please hold while I find him for you."

A long pause. Some classical music played. Marek put his hand over the phone and said to Elsie, "It's Doniger."

"Hey," she said. "You must rate. The big cheese himself."

"Why is Doniger calling me?"