She jumped back with fright when the man suddenly raised his hand toward her. Then she realized she'd caught her damp sleeve on his bracelet. She pulled it free. The hand dropped back with a thunk.

Marek took the man's broadsword. He gave the bow and arrows to her.

Several white monk's habits hung in a row on pegs on the wall. Marek slipped one on, gave a second one to her.

Now he pointed to the left, toward the ramp leading to the second building. Two soldiers in maroon and gray stood on the ramp, blocking their way.

Marek looked around, found a heavy stick used for stirring grain, and handed it to her. He saw more bottles of wine in the corner. He took two, opened the door, and said something in Occitan, waving the bottles at the soldiers. They hurried over. Marek pushed Kate to the side of the door and said one word: "Hard."

The first soldier came in, followed immediately by the second. She swung the stick at his head and hit him so hard she was sure she had broken his skull. But she hadn't; the man fell, but immediately started to get up again. She hit him two more times, and then he fell flat on his face and didn't move. Meanwhile, Marek had broken the wine bottle over the other soldier's head, and he was now kicking him repeatedly in the stomach. The man struggled, raising his arms to protect himself, until she brought the stick down on his head. Then he stopped moving.

Marek nodded, slipped the broadsword under his robes, and started across the ramp, head slightly bowed, like a monk. Kate followed behind.

She did not dare to look at the soldiers on the guard towers. She had concealed the quiver under her robes, but she had to carry the bow outside, in plain view. She didn't know if anybody had noticed her or not. They came to the next building, and Marek paused at the door. They listened, but heard nothing except a loud repetitive banging and the rush of the river below.

Marek opened the door.

Chris coughed and sputtered, bobbing in the river. The current was slower now, but he was already a hundred yards downstream from the mill. On both sides of the river, Arnaut's men were standing around, obviously waiting for the order to attack the bridge. A large number of horses stood nearby, held by pages.

The sun reflected brightly off the surface of the water into the faces of Arnaut's men. He saw them squinting, and turning their backs to the river. The glare was probably why they hadn't seen him, Chris realized.

Without splashing or raising his arms, he made his way to the north bank of the Dordogne and slipped among overhanging rushes at the water's edge. Here no one would see him. He could catch his breath for a moment. And he had to be on this side of the river - the French side - if he hoped to rejoin André and Kate.

That is, assuming they made it out of the mill alive. Chris didn't know what the chances of that were. The mill was crawling with soldiers.

And then he remembered that Marek still had the ceramic. If Marek died, or disappeared, they'd never get back home. But they'd probably never get back anyway, he thought.

Something thumped the back of his head. He turned to see a dead rat, bloated with gas, floating in the water. The moment of revulsion spurred him to get out of the river. There were no soldiers right where he was now; they were standing in the shade of an oak grove, a dozen yards downstream. He climbed out of the water and sank down in the undergrowth. He felt the sun on his body, warming him. He heard the soldiers laughing and joking. He knew he should move to a more secluded place. Where he was now, lying among low bushes on the shore, anyone walking along the riverside trail would easily see him. But as he felt warmer, he also felt overcome with exhaustion. His eyes were heavy, his limbs weary, and despite his sense of danger, he told himself, he would close his eyes just for a few moments.

Just for a few moments.

Inside the mill, the noise was deafening. Kate winced as she stepped onto the second-floor landing and looked down on the room below. Running the length of the building, twin rows of trip-hammers clanged down on blacksmith's anvils, making a continuous banging that reverberated off the stone walls.

Beside each anvil was a tub of water and a brazier with glowing coals. This was clearly a forge, where steel was annealed by alternately heating, pounding and cooling in water; the wheels provided the pounding force.

But now, the trip-hammers were banging down unattended as seven or eight uniformed soldiers in maroon and gray methodically searched every corner of the room, looking beneath the rotating cylinders and under the banging hammers, feeling the walls for secret compartments in the stone, and rummaging through the chests of tools.

She had no doubt what they were looking for: Brother Marcel's key.

Marek turned to her and signaled that they should go down the stairs and toward a side door, now standing ajar. This was the only door in the side wall; it had no lock, and it was almost certainly Marcel's room.

And clearly, it had already been searched.

For some reason, this didn't bother Marek, who went down intently. At the foot of the stairs, they made their way past the banging trip-hammers and slipped inside Marcel's room.

Marek shook his head.

This was indeed a monk's cell, very small, and strikingly bare: just a narrow cot, a basin of water and a chamber pot. By the bed stood a tiny table with a candle. That was all. Two of Marcel's white robes hung on a peg inside the door.

Nothing else.

It was clear from a glance that there were no keys in this room. And even if there had been, the soldiers would already have found them.

Nevertheless, to Kate's surprise, Marek got down on his hands and knees and began to search methodically under the bed.

Marek was remembering what the Abbot had said just before he was killed.

The Abbot didn't know the location of the passage, and he desperately wanted to find out, so he could provide it to Arnaut. The Abbot had encouraged the Professor to search through old documents - which made sense, if Marcel was so demented that he could no longer tell anybody what he had done.

The Professor had found a document that mentioned a key, and he seemed to think this was a discovery of importance. But the Abbot had been impatient: "Of course there is a key. Marcel has many keys…"

So the Abbot already knew about the existence of a key. He knew where the key was. But he still couldn't use it.

Why not?

Kate tapped Marek on the shoulder. He looked over, to see she had pushed aside the white robes. On the back of the door he saw three carved designs, in some Roman pattern. The designs had a formal, even decorative quality that seemed distinctly unmedieval.

And then he realized that these weren't designs at all. They were explanatory diagrams.

They were keys.

The diagram that held his attention was the third one, on the far right side. It looked like this:

The diagram had been carved in the wood of the door many years before. Undoubtedly, the soldiers had already seen it. But if they were still searching, then they hadn't understood what it meant.

But Marek understood.

Kate was staring at him, and she mouthed, Staircase?

Marek pointed to the image. He mouthed, Map.

Because now at last it was all clear to him.

VIVIX wasn't found in the dictionary, because it wasn't a word. It was a series of numerals: V, IV and IX. And these numerals had specific directions attached to them, as indicated by the text in the parchment: DESIDE. Which was also not a word, but rather stood for DExtra, SInistra, DExtra. Or in Latin: "right, left, right."

Therefore, the key was this: once inside the green chapel, you walked five paces to the right, four paces to the left and nine paces to the right.