All the while, the narrow tunnel calledIl Passetto stretched out before Langdon and Vittoria as they dashed toward Vatican City. The torch in Langdon's hand threw only enough light to see a few yards ahead. The walls were close on either side, and the ceiling low. The air smelled dank. Langdon raced on into the darkness with Vittoria close at his heels.

The tunnel inclined steeply as it left the Castle St. Angelo, proceeding upward into the underside of a stone bastion that looked like a Roman aqueduct. There, the tunnel leveled out and began its secret course toward Vatican City.

As Langdon ran, his thoughts turned over and over in a kaleidoscope of confounding images -- Kohler, Janus, the Hassassin, Rocher… a sixth brand? I'm sure you've heard about the sixth brand, the killer had said. The most brilliant of all. Langdon was quite certain he had not. Even in conspiracy theory lore, Langdon could think of no references to any sixth brand. Real or imagined. There were rumors of a gold bullion and a flawless Illuminati Diamond but never any mention of a sixth brand.

"This crisis has made CERN look like monsters! Max wouldnever do anything to damage CERN's reputation!"

Impossiblewas one word Langdon had stopped using tonight. "I don't know," Langdon yelled as they ran. "Kohler has a serious grudge, and he also has some serious influence."

On one count, Langdon knew CERN had taken a public beating tonight, all because of the Illuminati's insistence on making this a public spectacle. And yet, he wondered how much CERN hadreally been damaged. Criticism from the church was nothing new for CERN. In fact, the more Langdon thought about it, the more he wondered if this crisis might actuallybenefit CERN. If publicity were the game, then antimatter was the jackpot winner tonight. The entire planet was talking about it.

"Kohler can't be Janus!" Vittoria declared as they ran down the interior of the dike. "It's impossible!"

"You know what promoter P. T. Barnum said," Langdon called over his shoulder. " 'I don't care what you say about me, just spell my name right!' I bet people are already secretly lining up to license antimatter technology. And after they see its true power at midnight tonight…"

Vittoria was silent as they dashed down the tunnel.

"Illogical," Vittoria said. "Publicizing scientific breakthroughs is not about showing destructive power! This isterrible for antimatter, trust me!"

Langdon's torch was fading now. "Then maybe it's all much simpler than that. Maybe Kohler gambled that the Vatican would keep the antimatter a secret -- refusing to empower the Illuminati by confirming the weapon's existence. Kohler expected the Vatican to be their usual tight-lipped selves about the threat, but the camerlegno changed the rules."

Suddenly the scenario was making more sense to Langdon. "Yes! Kohler never counted on the camerlegno's reaction. The camerlegno broke the Vatican tradition of secrecy and went public about the crisis. He was dead honest. He put the antimatter on TV, for God's sake. It was a brilliant response, and Kohler never expected it. And the irony of the whole thing is that the Illuminati attack backfired. It inadvertently produced a new church leader in the camerlegno. And now Kohler is coming to kill him!"

"Max is a bastard," Vittoria declared, "but he is not a murderer. And he wouldnever have been involved in my father's assassination."

In Langdon's mind, it was Kohler's voice that answered. Leonardo was considered dangerous by many purists at CERN. Fusing science and God is the ultimate scientific blasphemy. "Maybe Kohler found out about the antimatter project weeks ago and didn't like the religious implications."

"So hekilled my father over it? Ridiculous! Besides, Max Kohler would never haveknown the project existed."

"While you were gone, maybe your father broke down and consulted Kohler, asking for guidance. You yourself said your father was concerned about the moral implications of creating such a deadly substance."

"Asking moral guidance from Maximilian Kohler?" Vittoria snorted. "I don't think so!"

"Besides," Vittoria argued, "why would Kohler have bothered to call you in this morning and ask for help ifhe is behind the whole thing?"

The tunnel banked slightly westward. The faster they ran, the dimmer Langdon's torch became. He began to fear what the place would look like if the light went out. Black.

The thought of beingused by Kohler incensed Langdon. Langdon's involvement had given the Illuminati a level of credibility. His credentials and publications had been quoted all night by the media, and as ridiculous as it was, the presence of a Harvard professor in Vatican City had somehow raised the whole emergency beyond the scope of paranoid delusion and convinced skeptics around the world that the Illuminati brotherhood was not only a historical fact, but a force to be reckoned with.

"What!" Vittoria stumbled behind him. She pulled herself up and ran on. "Hesaid that!?"

"On air. He likened CERN to the Masonic lodges -- an innocent organization unknowingly harboring the Illuminati brotherhood within."

"That BBC reporter," Langdon said, "thinks CERN is the new Illuminati lair."

"My God, this is going to destroy CERN."

Langdon had already considered it. "By calling me, Kohler covered his bases. He made sure no one would accuse him of nonaction in the face of crisis. He probably never expected us to get this far."

Langdon was not so sure. Either way, the theory suddenly seemed less far-fetched. CERN was the ultimate scientific haven. It was home to scientists from over a dozen countries. They seemed to have endless private funding. And Maximilian Kohler was their director.

"Probably trying to stop this madness. Show support. Maybe he really is acting as the Samaritan! He could have found out who knew about the antimatter project and has come to share information."

"The killer said he was coming to brand the camerlegno."

Kohler is Janus.

Langdon considered it. Maybe that was the point.

"If Kohler's not involved," Langdon challenged, "then what is he doing here?"

"Listen to yourself! It would be a suicide mission. Max would never get out alive."

Langdon breathed a sigh of relief, realizing as he had suspected, that the ancient tunnel was in use. Recently. As in today. He now had little doubt that four terrified cardinals had been secreted through here earlier.

The outline of a steel gate loomed ahead, blocking their progress down the tunnel. Langdon's heart almost stopped. When they approached, however, they found the ancient lock hanging open. The gate swung freely.

They ran on. Langdon could now hear the sounds of chaos to his left. It was St. Peter's Square. They were getting close.

He felt a surge of panic. In architect-speak, this rare kind of door was called asenza chiave -- a one-way portal, used for security, and only operable from one side -- the other side. Langdon's hope dimmed to black… along with the torch in his hand.

With a scream of frustration, Langdon swung the torch and started pounding on the door.

They hit another gate, this one heavier. It too was unlocked. The sound of St. Peter's Square faded behind them now, and Langdon sensed they had passed through the outer wall of Vatican City. He wondered where inside the Vatican this ancient passage would conclude. In the gardens? In the basilica? In the papal residence?

The cumbrous door blocking their way was a thick wall of riveted iron. Even by the last flickers of his torch, Langdon could see that the portal was perfectly smooth -- no handles, no knobs, no keyholes, no hinges. No entry.

11:29 P. M.

Then, without warning, the tunnel ended.

He looked at his watch. Mickey glowed.