"At least there's nobody over there," Sophie whispered.

Langdon and Sophie moved slowly down the north aisle, keeping to the shadows behind the ample pillars that separated it from the open nave. Despite having traveled more than halfway down the nave, they still had no clear view of Newton's tomb. The sarcophagus was recessed in a niche, obscured from this oblique angle.

Sophie had already stepped from the shadows and was headed across the open floor.

"-- is watching," Langdon sighed, hurrying to join her.

Langdon shook his head, also surprised.

Langdon nodded, relieved. The entire section of the nave near Newton's tomb was deserted. "I'll go over," he whispered. "You should stay hidden just in case someone --"

Crossing the massive nave on a diagonal, Langdon and Sophie remained silent as the elaborate sepulchre revealed itself in tantalizing increments… a black-marble sarcophagus… a reclining statue of Newton… two winged boys… a huge pyramid… and… an enormous orb.

"Did you know about that?" Sophie said, sounding startled.

As they approached the niche, Langdon felt a slow sinking sensation. Newton's tomb was covered with orbs -- stars, comets, planets. You seek the orb that ought be on his tomb? It could turn out to be like trying to find a missing blade of grass on a golf course.

"Astronomical bodies," Sophie said, looking concerned. "And a lot of them."

"Those look like constellations carved on it," Sophie said.

Sophie moved directly to the sarcophagus, but Langdon hung back a few feet, keeping an eye on the abbey around them.

Langdon stepped closer, considering it. "Principia Mathematica, as I remember, has something to do with the gravitation pull of planets… which admittedly are orbs, but it seems a little far-fetched."

Langdon frowned. The only link between the planets and the Grail that Langdon could imagine was the pentacle of Venus, and he had already tried the password "Venus" en route to the Temple Church.

"Divinity," Sophie said, tilting her head and reading the titles of the books on which Newton was leaning. "Chronology. Opticks. Philosophiae Naturalis Principia Mathematica?" She turned to him. "Ring any bells?"

"How about the signs of the zodiac?" Sophie asked, pointing to the constellations on the orb. "You were talking about Pisces and Aquarius earlier, weren't you?"

The End of Days, Langdon thought. "The end of Pisces and the beginning of Aquarius was allegedly the historical marker at which the Priory planned to release the Sangreal documents to the world." But the millennium came and went without incident, leaving historians uncertain when the truth was coming.

"You told me earlier," she said, "that the timing of the Priory's plans to unveil the truth about 'the Rose' and her fertile womb was linked directly to the position of planets -- orbs."

"It seems possible," Sophie said, "that the Priory's plans to reveal the truth might be related to the last line of the poem."

Langdon nodded, feeling the first faint wisps of possibility materializing. Even so, his intuition told him astronomy was not the key. The Grand Master's previous solutions had all possessed an eloquent, symbolic significance -- the Mona Lisa, Madonna of the Rocks, SOFIA. This eloquence was definitely lacking in the concept of planetary orbs and the zodiac. Thus far, Jacques Saunière had proven himself a meticulous code writer, and Langdon had to believe that his final password -- those five letters that unlocked the Priory's ultimate secret -- would prove to be not only symbolically fitting but also crystal clear. If this solution were anything like the others, it would be painfully obvious once it dawned.

It speaks of Rosy flesh and seeded womb. Langdon felt a shiver of potential. He had not considered the line that way before.

Scrawled on the sarcophagus lid, at Newton's feet, shimmered a barely visible charcoal-pencil message:

Langdon did not understand her concern. A careless tourist had left a charcoal, grave-rubbing pencil on the sarcophagus lid near Newton's foot. It's nothing. Langdon reached out to pick it up, but as he leaned toward the sarcophagus, the light shifted on the polished black-marble slab, and Langdon froze. Suddenly, he saw why Sophie was afraid.

"Look!" Sophie gasped, jarring his thoughts as she grabbed his arm. From the fear in her touch Langdon sensed someone must be approaching, but when he turned to her, she was staring aghast at the top of the black marble sarcophagus. "Someone was here," she whispered, pointing to a spot on the sarcophagus near Newton's outstretched right foot.

Go through Chapter House, out south exit, to public garden.

I have Teabing.

Sophie turned and scanned the nave.

Langdon read the words twice, his heart pounding wildly.

Despite the pall of trepidation that settled over him upon seeing the words, Langdon told himself this was good news.

Sophie nodded. Otherwise why make their presence known?

Leigh is still alive. There was another implication here too. "They don't know the password either," he whispered.

"Or it's a trap."

Langdon shook his head. "I don't think so. The garden is outside the abbey walls. A very public place." Langdon had once visited the abbey's famous College Garden -- a small fruit orchard and herb garden -- left over from the days when monks grew natural pharmacological remedies here. Boasting the oldest living fruit trees in Great Britain, College Garden was a popular spot for tourists to visit without having to enter the abbey. "I think sending us outside is a show of faith. So we feel safe."

"They may want to trade Leigh for the password."

Sophie looked dubious. "You mean outside, where there are no metal detectors?"

Langdon scowled. She had a point.

Gazing back at the orb-filled tomb, Langdon wished he had some idea about the cryptex password… something with which to negotiate. I got Leigh involved in this, and I'll do whatever it takes if there is a chance to help him.

CLOISTERS

The idea was a good one. Langdon vaguely recalled the Chapter House as a huge octagonal hall where the original British Parliament convened in the days before the modern Parliament building existed. It had been years since he had been there, but he remembered it being out through the cloister somewhere. Taking several steps back from the tomb, Langdon peered around the choir screen to his right, across the nave to the side opposite that which they had descended.

COLLEGE HALL

THIS WAY TO:

"The note says to go through the Chapter House to the south exit," Sophie said. "Maybe from the exit we would have a view of the garden? That way we could assess the situation before we walked out there and exposed ourselves to any danger?"

Langdon and Sophie were jogging as they passed beneath the sign, moving too quickly to notice the small announcement apologizing that certain areas were closed for renovations.

DEANERY

PYX CHAMBER

A gaping vaulted passageway stood nearby, with a large sign.

ST. FAITH'S CHAPEL

MUSEUM

CHAPTER HOUSE

They emerged immediately into a high-walled, open-roof courtyard through which morning rain was falling. Above them, the wind howled across the opening with a low drone, like someone blowing over the mouth of a bottle. Entering the narrow, low-hanging walkways that bordered the courtyard perimeter, Langdon felt the familiar uneasiness he always felt in enclosed spaces. These walkways were called cloisters, and Langdon noted with uneasiness that these particular cloisters lived up to their Latin ties to the word claustrophobic.

Forty yards down the east cloister, an archway materialized on their left, giving way to another hallway. Although this was the entrance they were looking for, the opening was cordoned off by a swag and an official-looking sign.

The rain was spitting now, and the walkway was cold and damp with gusts of rain that blew through the lone pillared wall that was the cloister's only source of light. Another couple scurried past them the other way, hurrying to get out of the worsening weather. The cloisters looked deserted now, admittedly the abbey's least enticing section in the wind and rain.

Focusing his mind straight ahead toward the end of the tunnel, Langdon followed the signs for the Chapter House.

PYX CHAMBER

CLOSED FOR RENOVATION

ST. FAITH'S CHAPEL

Sophie was already stepping over the swag and moving forward.

CHAPTER HOUSE

The long, deserted corridor beyond the swag was littered with scaffolding and drop cloths. Immediately beyond the swag, Langdon could see the entrances to the Pyx Chamber and St. Faith's Chapel on the right and left. The entrance to the Chapter House, however, was much farther away, at the far end of the long hallway.

Even from here, Langdon could see that its heavy wooden door was wide open, and the spacious octagonal interior was bathed in a grayish natural light from the room's enormous windows that looked out on College Garden. "Go through Chapter House, out south exit, to public garden."

"We just left the east cloister," Langdon said, "so the south exit to the garden must be through there and to the right."

As they hurried down the dark corridor, the sounds of the wind and rain from the open cloister faded behind them. The Chapter House was a kind of satellite structure -- a freestanding annex at the end of the long hallway to ensure the privacy of the Parliament proceedings housed there.

"It looks huge," Sophie whispered as they approached.

Langdon had forgotten just how large this room was. Even from outside the entrance, he could gaze across the vast expanse of floor to the breathtaking windows on the far side of the octagon, which rose five stories to a vaulted ceiling. They would certainly have a clear view of the garden from in here.

Crossing the threshold, both Langdon and Sophie found themselves having to squint. After the gloomy cloisters, the Chapter House felt like a solarium. They were a good ten feet into the room, searching the south wall, when they realized the door they had been promised was not there.

The lone man who had been standing behind the door looked calm as he aimed a small revolver at them. He was portly and was propped on a pair of aluminum crutches.

They were standing in an enormous dead end.

The creaking of a heavy door behind them made them turn, just as the door closed with a resounding thud and the latch fell into place.

For a moment Langdon thought he must be dreaming.

It was Leigh Teabing.