Eleven-forty-two P. M.

Vittoria and the guards arrived immediately. Flashlights came on, but the lights were almost dead now and did not even begin to probe the depths of the basilica before them. The beams swept back and forth, revealing only columns and bare floor. The camerlegno was nowhere to be seen.

The frenzied convoy that plunged back into the basilica to retrieve the camerlegno was not one Langdon had ever imagined he would be part of… much less leading. But he had been closest to the door and had acted on instinct.

The wall of blackness that hit Langdon was absolute. His pupils were contracted from the glare outside, and his field of vision now extended no farther than a few feet before his face. He skidded to a stop. Somewhere in the blackness ahead, he heard the camerlegno's cassock rustle as the priest ran blindly into the abyss.

"Camerlegno!" Chartrand yelled, fear in his voice. "Wait! Signore!"

He'll die in here, Langdon thought, sprinting over the threshold into the darkened void. "Camerlegno! Stop!"

But Macri and Glick kept coming.

A commotion in the doorway behind them caused everyone to turn. Chinita Macri's large frame lurched through the entry. Her camera was shouldered, and the glowing red light on top revealed that it was still transmitting. Glick was running behind her, microphone in hand, yelling for her to slow down.

"Out!" Chartrand snapped. "This is not for your eyes!"

Langdon could not believe these two. This is not the time!

Macri ignored him. She threw a switch on her camera. The spotlight on top glared to life, blinding everyone.

"Chinita!" Glick sounded fearful now. "This is suicide! I'm not coming!"

Langdon shielded his face and turned away in pain. Damn it! When he looked up, though, the church around them was illuminated for thirty yards.

Macri wheeled her camera toward the sound. Far off, in the grayness at the end of the spotlight's reach, black fabric billowed, revealing a familiar form running down the main aisle of the basilica.

At that moment the camerlegno's voice echoed somewhere in the distance. "Upon this rock I will build my church!"

Macri brought up the rear, lighting everyone's way and transmitting the sepulchral chase to the world. An unwilling Glick cursed aloud as he tagged along, fumbling through a terrified blow-by-blow commentary.

The main aisle of St. Peter's Basilica, Lieutenant Chartrand had once figured out, was longer than an Olympic soccer field. Tonight, however, it felt like twice that. As the guard sprinted after the camerlegno, he wondered where the man was headed. The camerlegno was clearly in shock, delirious no doubt from his physical trauma and bearing witness to the horrific massacre in the Pope's office.

There was a fleeting instant of hesitation as everyone's eyes took in the bizarre image. Then the dam broke. Chartrand pushed past Langdon and sprinted after the camerlegno. Langdon took off next. Then the guards and Vittoria.

Chartrand knew the man was shouting Scripture -- Matthew 16:18, if Chartrand recalled correctly. Upon this rock I will build my church. It was an almost cruelly inapt inspiration -- the church was about to be destroyed. Surely the camerlegno had gone mad.

Somewhere up ahead, beyond the reach of the BBC spotlight, the camerlegno's voice rang out joyously. "Upon this rock I will build my church!"

Or had he?

Fifty yards ahead, in the center of the church, a ghost appeared… a diaphanous, glowing outline. The pale shape was that of the half-naked camerlegno. The specter seemed transparent, radiating light. Chartrand staggered to a stop, feeling a knot tighten in his chest. The camerlegno is glowing! The body seemed to shine brighter now. Then, it began to sink… deeper and deeper, until it disappeared as if by magic into the blackness of the floor.

For a fleeting instant, Chartrand's soul fluttered. Holy visions and divine messages had always seemed like wishful delusions to him -- the product of overzealous minds hearing what they wanted to hear -- God did not interactdirectly!

Langdon had seen the phantom also. For a moment, he too thought he had witnessed a magical vision. But as he passed the stunned Chartrand and ran toward the spot where the camerlegno had disappeared, he realized what had just happened. The camerlegno had arrived at the Niche of the Palliums -- the sunken chamber lit by ninety-nine oil lamps. The lamps in the niche shone up from beneath, illuminating him like a ghost. Then, as the camerlegno descended the stairs into the light, he had seemed to disappear beneath the floor.

A moment later, though, as if the Holy Spirit Himself had descended to persuade Chartrand of His power, Chartrand had a vision.

The camerlegno yanked open the doors and ran inside. Oddly though, he totally ignored the golden box, rushing right past it. Five feet beyond the box, he dropped to his knees and began struggling to lift an iron grate embedded in the floor.

What is he doing? Langdon wondered. Certainly he can't think the golden box --

Langdon watched in horror, now realizing where the camerlegno was headed. Good God, no! He dashed down the stairs after him. "Father! Don't!"

Langdon arrived breathless at the rim overlooking the sunken room. He peered down the stairs. At the bottom, lit by the golden glow of oil lamps, the camerlegno dashed across the marble chamber toward the set of glass doors that led to the room holding the famous golden box.

As Langdon opened the glass doors and ran toward the camerlegno, he saw the camerlegno heave on the grate. The hinged, iron bulkhead fell open with a deafening crash, revealing a narrow shaft and a steep stairway that dropped into nothingness. As the camerlegno moved toward the hole, Langdon grabbed his bare shoulders and pulled him back. The man's skin was slippery with sweat, but Langdon held on.

"Father," Langdon urged, as calmly as possible, "you can't go down there. We need to evacuate."

"My son," the camerlegno said, his voice eerily sane. "I have just had a message. I know --"

Langdon was surprised when their eyes met. The camerlegno no longer had the glazed look of a man in a trance. His eyes were keen, glistening with a lucid determination. The brand on his chest looked excruciating.

"Camerlegno!" It was Chartrand and the others. They came dashing down the stairs into the room, lit by Macri's camera.

When Chartrand saw the open grate in the floor, his eyes filled with dread. He crossed himself and shot Langdon a thankful look for having stopped the camerlegno. Langdon understood; had read enough about Vatican architecture to know what lay beneath that grate. It was the most sacred place in all of Christendom. Terra Santa. Holy Ground. Some called it the Necropolis. Some called it the Catacombs. According to accounts from the select few clergy who had descended over the years, the Necropolis was a dark maze of subterranean crypts that could swallow a visitor whole if he lost his way. It was not the kind of place through which they wanted to be chasing the camerlegno.

The camerlegno wheeled, obviously startled. "What are you doing!"

Everyone stared.

"Signore," Chartrand pleaded. "You're in shock. We need to leave this place. You cannot go down there. It's suicide."

The camerlegno turned to the group. "Upon this rock I will build my church. That was the message. The meaning is clear."

The camerlegno seemed suddenly stoic. He reached out and put a quiet hand on Chartrand's shoulder. "Thank you for your concern and service. I cannot tell you how. I cannot tell you I understand. But I have had a revelation. I know where the antimatter is."

Macri moved in for a closer shot. Glick was mute, as if shell-shocked.

Langdon was still unable to comprehend the camerlegno's conviction that he had spoken to God, much less that he had deciphered the message. Upon this rock I will build my church? They were the words spoken by Jesus when he chose Peter as his first apostle. What did they have to do with anything?

The camerlegno spoke quickly now. "The Illuminati have placed their tool of destruction on the very cornerstone of this church. At the foundation." He motioned down the stairs. "On the very rock upon which this church was built. And I know where that rock is."

Langdon was certain the time had come to overpower the camerlegno and carry him off. As lucid as he seemed, the priest was talking nonsense. A rock? The cornerstone in the foundation? The stairway before them didn't lead to the foundation, it led to the necropolis! "The quote is a metaphor, Father! There is no actualrock!"

The camerlegno looked strangely sad. "Thereis a rock, my son." He pointed into the hole."Pietro è la pietra."

Peter's faith in God was so steadfast that Jesus called Peter "the rock" -- the unwavering disciple on whose shoulders Jesus would build his church. On this very location, Langdon realized -- Vatican Hill -- Peter had been crucified and buried. The early Christians built a small shrine over his tomb. As Christianity spread, the shrine got bigger, layer upon layer, culminating in this colossal basilica. The entire Catholic faith had been built, quite literally, upon St. Peter. The rock.

Langdon froze. In an instant it all came clear.

Pietro è la pietra. Peter is the rock.

The austere simplicity of it gave him chills. As Langdon stood there with the others, staring down the long staircase, he realized that there was indeed a rock buried in the darkness beneath this church.

Despite the seemingly supernatural origin of the information, Langdon sensed a stark logic in it. Placing the antimatter on St. Peter's tomb seemed painfully obvious now. The Illuminati, in an act of symbolic defiance, had located the antimatter at the core of Christendom, both literally and figuratively. The ultimate infiltration.

"The antimatter is on St. Peter's tomb," the camerlegno said, his voice crystalline.

"And if you all need worldly proof," the camerlegno said, sounding impatient now, "I just found that grate unlocked."

An instant later, with deceptive agility, the camerlegno spun, grabbed an oil lamp, and headed for the opening.

Everyone stared into the hole.

He pointed to the open bulkhead in the floor. "It isnever unlocked. Someone has been down there…recently."