"Carefully," Teabing urged. "Ever so carefully."

Sophie aligned the final dial. "Okay," she whispered, glancing up at the others. "I'm going to pull it apart."

S… O… F…

Sophie felt a wild excitement as she cradled the cryptex and began dialing in the letters. An ancient word of wisdom frees this scroll. Langdon and Teabing seemed to have stopped breathing as they looked on.

…I…A.

"Remember the vinegar," Langdon whispered with fearful exhilaration. "Be careful."

Sophie knew that if this cryptex were like those she had opened in her youth, all she would need to do is grip the cylinder at both ends, just beyond the dials, and pull, applying slow, steady pressure in opposite directions. If the dials were properly aligned with the password, then one of the ends would slide off, much like a lens cap, and she could reach inside and remove the rolled papyrus document, which would be wrapped around the vial of vinegar. However, if the password they had entered were incorrect, Sophie's outward force on the ends would be transferred to a hinged lever inside, which would pivot downward into the cavity and apply pressure to the glass vial, eventually shattering it if she pulled too hard.

Teabing and Langdon both leaned in as Sophie wrapped her palms around the ends of the cylinder.

Pull gently, she told herself.

In the excitement of deciphering the code word, Sophie had almost forgotten what they expected to find inside. This is the Priory keystone. According to Teabing, it contained a map to the Holy Grail, unveiling the tomb of Mary Magdalene and the Sangreal treasure… the ultimate treasure trove of secret truth.

Suddenly, the stone slid apart like a well-crafted telescope. The heavy end piece detached in her hand. Langdon and Teabing almost jumped to their feet. Sophie's heart rate climbed as she set the end cap on the table and tipped the cylinder to peer inside.

Peering down the hollow of the rolled paper, Sophie could see it had been wrapped around a cylindrical object -- the vial of vinegar, she assumed. Strangely, though, the paper around the vinegar was not the customary delicate papyrus but rather, vellum. That's odd, she thought, vinegar can't dissolve a lambskin vellum. She looked again down the hollow of the scroll and realized the object in the center was not a vial of vinegar after all. It was something else entirely.

Now gripping the stone tube, Sophie double-checked that all of the letters were properly aligned with the indicator. Then, slowly, she pulled. Nothing happened. She applied a little more force.

A scroll!

Langdon stared in amazement. I see Saunière has no intention of making this easy.

Black -- male.

"No." Sophie unrolled the scroll and revealed what was wrapped inside. "For this."

"That's not papyrus," Teabing said. "It's too heavy."

Frowning, Sophie grabbed the rolled vellum and the object around which it was wrapped, pulling them both out of the container.

When Langdon saw the object inside the sheet of vellum, his heart sank.

"God help us," Teabing said, slumping. "Your grandfather was a pitiless architect."

Reaching over, Langdon lifted the smaller cryptex. It looked identical to the first, except half the size and black. He heard the familiar gurgle. Apparently, the vial of vinegar they had heard earlier was inside this smaller cryptex.

Black nested within white. Langdon felt the web of symbolism stretching onward. White gives birth to black.

On the table sat a second cryptex. Smaller. Made of black onyx. It had been nested within the first.

"For what? The vial of vinegar?"

White -- female.

Every man sprang from woman.

Saunière's passion for dualism. Two cryptexes. Everything in pairs. Double entendres. Male female.

"What's wrong?" Teabing asked. "Pull out the scroll."

"I know. It's padding."

"You'll be pleased to hear that at least we're flying in the right direction." Langdon examined the thick vellum sheet. Written in ornate penmanship was another four-line verse. Again, in iambic pentameter. The verse was cryptic, but Langdon needed to read only as far as the first line to realize that Teabing's plan to come to Britain was going to pay off. IN LONDON LIES A KNIGHT A POPE INTERRED.

"Well, Robert," Teabing said, sliding the page of vellum over to him.

The remainder of the poem clearly implied that the password for opening the second cryptex couldbe found by visiting this knight's tomb, somewhere in the city.

Teabing grinned. "Not the foggiest. But I know in precisely which crypt we should look."

At that moment, fifteen miles ahead of them, six Kent police cars streaked down rain-soaked streets toward Biggin Hill Executive Airport.

Langdon turned excitedly to Teabing. "Do you have any idea what knight this poem is referring to?"