03:10:12

In the windowless control room above the transit pad, Gordon and Stern stared at the monitor screen. It showed an image of five panels, representing the five glass containers that had been etched. As they watched, small white dots appeared on the panels.

"That's the position of the etch points," Gordon said.

Each point was accompanied by a cluster of numbers, but they were too small to read.

"That's the size and depth of each etching," Gordon said.

Stern said nothing. The simulation continued. The panels began to fill with water, represented by a rising horizontal blue line. Superimposed on each panel were two large numbers: the total weight of the water an the pressure per square inch on the glass surface, at the bottom of each panel, where the pressure was greatest.

Even though the simulation was highly stylized, Stern found himself holding his breath. The waterline went higher, and higher.

One tank began to leak: a flashing red spot.

"One leaking," Gordon said.

A second tank began to leak, and as the water continued to rise, a jagged lightning streak crossed the panel, and it vanished from the screen.

"One shattered."

Stern was shaking his head. "How rough do you think this simulation is?"

"Pretty fast and dirty."

On the screen, a second tank shattered. The final two filled to the top without incident.

"So," Gordon said. "The computer's telling us three out of five panels can't be filled."

"If you believe it. Do you?"

"Personally, I don't," Gordon said. "The input data's just not good enough, and the computer is making all kinds of stress assumptions that are pretty hypothetical. But I think we better fill those tanks at the last minute."

Stern said, "It's too bad there isn't a way to strengthen the tanks."

Gordon looked up quickly. "Like what?" he said. "You have an idea?"

"I don't know. Maybe we could fill the etchings with plastic, or some kind of putty. Or maybe we could-"

Gordon was shaking his head. "Whatever you do, it has to be uniform. You'd have to cover the entire surface of the tank evenly. Perfectly evenly."

"I can't see any way to do that," Stern said.

"Not in three hours," Gordon said. "And that's what we have left."

Stern sat down in a chair, frowning. For some reason, he was thinking of racing cars. A succession of images flashed through his mind. Ferraris. Steve McQueen. Formula One. The Michelin Man with his rubber tube body. The yellow Shell sign. Big truck tires, hissing in rain. B. F. Goodrich.

He thought, I don't even like cars. Back in New Haven, he owned an ancient VW Bug. Clearly, his racing mind was trying to avoid an unpleasant reality - something he didn't want to face up to.

The risk.

"So we just fill the panels at the last minute, and pray?" Stern said.

"Exactly," Gordon said. "That's exactly what we do. It's a little hairy. But I think it'll work."

"And the alternative?" Stern said.

Gordon shook his head. "Block their return. Don't let your friends come back. Get brand new glass panels down here, panels that don't have imperfections, and set up again."

"And that takes how long?"

"Two weeks."

"No," Stern said. "We can't do that. We have to go for it."

"That's right," Gordon said. "We do."

02:55:14

Marek and Johnston climbed the circular stairs. At the top, they met de Kere, who was looking smugly satisfied. They stood once more on the wide battlements of La Roque. Oliver was there, pacing, red-faced and angry.

"Do you smell it?" he cried, pointing off toward the field, where Arnaut's troops continued to mass.

It was now early evening; the sun was down, and Marek guessed it must be about six o'clock. But in the fading light, they saw that Arnaut's forces now had a full dozen trebuchets assembled and set out in staggered rows on the field below. After the example of the first incendiary arrow, they had moved their engine farther apart, so that any fire would not spread beyond one engine.

Beyond the trebuchets, there was a staging area, with troops huddled around smoking fires. And at the very rear, the hundreds of tents of the soldiers nestled back against the dark line of the forest.

It looked, Marek thought, perfectly ordinary. The start of a siege. He couldn't imagine what Oliver was upset about.

A distinct burning odor drifted toward them from the smoking fires. It reminded Marek of the smell that roofers made. And with good reason: it was the same substance. "I do, my Lord," Johnston said. "It is pitch."

Johnston's blank expression conveyed that he, too, did not know why Oliver was so upset. It was standard practice in siege warfare to lob burning pitch over the castle walls.

"Yes, yes," Oliver said, "it is pitch. Of course it is pitch. But that is not all. Do you not smell it? They are mixing something with the pitch."

Marek sniffed the air, thinking Oliver was almost certainly right. When burning, pure pitch had a tendency to go out. Thus pitch was usually combined with other substances - oil, tow or sulfur - to make a more robustly burning mixture.

"Yes, my Lord," Johnston said. "I smell it."

"And what is it?" Oliver said in an accusing tone.

"Ceraunia, I believe."

"Also called the `thunderbolt stone'?"

"Yes, my Lord."

"And do we also employ this thunderbolt stone?"

"No, my Lord-" Johnston began.

"Ah! I thought as much."

Oliver was now nodding to de Kere, as if their suspicions were confirmed. Clearly, de Kere was behind all this.

"My Lord," Johnston said, "we have no need of the thunderbolt stone. We have better stone. We use pure sulfure."

"But sulfure is not the same." Another glance at de Kere.

"My Lord, it is. The thunderbolt stone is pyrite kerdonienne. When ground fine, it makes sulfure."

Oliver snorted. He paced. He glowered.

"And how," he said finally, "does Arnaut come to have this thunderbolt stone?"

"I cannot say," Johnston said, "but the thunderbolt stone is well known to soldiers. It is even mentioned in Pliny."

"You evade me with tricks, Magister. I speak not of Pliny. I speak of Arnaut. The man is an illiterate pig. He knows nothing of ceraunia, or the thunderbolt stone."

"My Lord-"

"Unless he is aided," Oliver said darkly. "Where are your assistants now?"

"My assistants?"

"Come, come, Magister, evade me no further."

"One is here," Johnston said, gesturing to Marek. "I am given that the second is dead, and I have no word of the third."

"And I believe," Oliver said, "that you know very well where they are. They are both working in the camp of Arnaut, even as we speak. That is how he comes to possess this arcane stone."

Marek listened to this with a growing sense of unease. Oliver had never seemed mentally stable, even in better times. Now, faced with impending attack, he was becoming openly paranoid - goaded by de Kere. Oliver seemed unpredictable, and dangerous.

"My Lord-" Johnston began.

"And further, I believe what I suspected from the first! You are the creature of Arnaut, for you have passed three days in Sainte-Mère, and the Abbot is the creature of Arnaut."

"My Lord, if you will hear-"

"I will not! You shall hear. I believe you work against me, that you, or your assistants, know the secret entrance to my castle, despite all your protestations, and that you plan to escape at the earliest moment - perhaps even tonight, under cover of Arnaut's attack."

Marek was carefully expressionless. That was, of course, exactly what they intended, if Kate ever found the entrance to the passage.

"Aha!" Oliver said, pointing at Marek. "You see? His jaw clenches. He knows what I say is true."