All is revealed at the thirty-third degree. Langdon glanced at the pot of water and then over at the pyramid. » Katherine, the pyramid is made out of solid granite and solid gold. Do you really think boiling water is hot enough to transform it?»

The smile on her face told Langdon that Katherine knew something he did not know. Confidently, she walked over to the island, lifted the gold-capped, granite pyramid, and set it in the strainer. Then she carefully lowered it into the bubbling water. «Let’s find out, shall we?»

High above the National Cathedral, the CIA pilot locked the helicopter in auto-hover mode and surveyed the perimeter of the building and the grounds. No movement. His thermal imaging couldn’t penetrate the cathedral stone, and so he couldn’t tell what the team was doing inside, but if anyone tried to slip out, the thermal would pick it up.

It was sixty seconds later that a thermal sensor pinged. Working on the same principle as home-security systems, the detector had identified a strong temperature differential. Usually this meant a human form moving through a cool space, but what appeared on the monitor was more of a thermal cloud, a patch of hot air drifting across the lawn. The pilot found the source, an active vent on the side of Cathedral College.

Probably nothing, he thought. He saw these kinds of gradients all the time. Someone cooking or doing laundry. As he was about to turn away, though, he realized something odd. There were no cars in the parking lot and no lights on anywhere in the building.

He studied the UH-60’s imaging system for a long moment. Then he radioed down to his team leader. «Simkins, it’s probably nothing, but. .»

«Incandescent temperature indicator!» Langdon had to admit, it was clever.

«It’s simple science,» Katherine said. «Different substances incandesce at different temperatures. We call them thermal markers. Science uses these markers all the time.»

Langdon gazed down at the submerged pyramid and capstone. Wisps of steam were beginning to curl over the bubbling water, although he was not feeling hopeful. He glanced at his watch, and his heart rate accelerated: 11:45 P.M. «You believe something here will luminesce as it heats up?»

«Not luminesce, Robert. Incandesce. There’s a big difference. Incandescence is caused by heat, and it occurs at a specific temperature. For example, when steel manufacturers temper beams, they spray a grid on them with a transparent coating that incandesces at a specific target temperature so they know when the beams are done. Think of a mood ring. Just put it on your finger, and it changes color from body heat.»

«Katherine, this pyramid was built in the 1800s! I can understand a craftsman making hidden release hinges in a stone box, but applying some kind of transparent thermal coating?»

«Perfectly feasible,» she said, glancing hopefully at the submerged pyramid. «The early alchemists used organic phosphors all the time as thermal markers. The Chinese made colored fireworks, and even the Egyptians — » Katherine stopped midsentence, staring intently into the roiling water.

«What?» Langdon followed her gaze into the turbulent water but saw nothing at all.

Katherine leaned in, staring more intently into the water. Suddenly she turned and ran across the kitchen toward the door.

«Where are you going?» Langdon shouted.

She slid to a stop at the kitchen light switch, flipped it off. The lights and exhaust fan went off, plunging the room into total darkness and silence. Langdon turned back to the pyramid and peered through the steam at the capstone beneath the water. By the time Katherine made it back to his side, his mouth had fallen open in disbelief.

Exactly as Katherine had predicted, a small section of the metal capstone was starting to glow beneath the water. Letters were starting to appear, and they were getting brighter as the water heated up.

«Text!» Katherine whispered.

Langdon nodded, dumbstruck. The glowing words were materializing just beneath the engraved inscription on the capstone. It looked like only three words, and although Langdon could not yet read what the words said, he wondered if they would unveil everything they had been looking for tonight. The pyramid is a real map, Galloway had told them, and it points to a real location.

As the letters shone brighter, Katherine turned off the gas, and the water slowly stopped churning. The capstone now came into focus beneath the water’s calm surface.

Three shining words were clearly legible.

CHAPTER 90

In the dim light of the cathedral college kitchen, langdon and katherine stood over the pot of water and stared at the transformed capstone beneath the surface. on the side of the golden capstone, an incandescent message was glowing.

Langdon read the shining text, scarcely able to believe his eyes. He knew the pyramid was rumored to reveal a specific location. . but he had never imagined that the location would be quite this specific.

Eight Franklin Square

«A street address,» he whispered, stunned.

Katherine looked equally amazed. «I don’t know what’s there, do you?»

Langdon shook his head. He knew Franklin Square was one of the older sections of Washington, but he wasn’t familiar with the address. He looked at the tip of the capstone, and read downward, taking in the entire text.

The secret hides within The Order

Eight Franklin Square

Is there some kind of Order on Franklin Square?

Is there a building that hides the opening to a deep spiral staircase?

Whether or not there was actually something buried at that address, Langdon had no idea. The important issue at this point was that he and Katherine had deciphered the pyramid and now possessed the information required to negotiate Peter’s release.

And not a moment too soon.

The glowing arms on Langdon’s Mickey Mouse watch indicated that they had less than ten minutes to spare.

«make the call,» katherine said, motioning to a phone on the wall in the kitchen. «now!»

The sudden arrival of this moment startled Langdon, and he found himself hesitating.

«Are we sure about this?»

«I most certainly am.»

«I’m not telling him anything until we know Peter is safe.»

«Of course not. You remember the number, right?»

Langdon nodded and made his way over to the kitchen phone. He lifted the receiver and dialed the man’s cell-phone number. Katherine came over and placed her head next to his so she could listen in. As the line began to ring, Langdon prepared himself for the eerie whisper of the man who had tricked him earlier tonight.

Finally, the call connected.

There was no greeting, though. No voice. Only the sound of breathing at the other end.

Langdon waited and then finally spoke. «I have the information you want, but if you want it, you’ll have to give us Peter.»

«Who is this?» a woman’s voice replied.

Langdon jumped. «Robert Langdon,» he said reflexively. «Who are you?» For an instant he thought he must have dialed incorrectly.

«Your name is Langdon?» The woman sounded surprised. «There’s someone here asking for you.»

What? «I’m sorry, who is this?»

«Officer Paige Montgomery with Preferred Security.» Her voice seemed shaky. «Maybe you can help us with this. About an hour ago, my partner responded to a 911 call in Kalorama Heights. . a possible hostage situation. I lost all contact with her, and so I called backup and came to check the residence. We found my partner dead in the backyard. The home owner was gone, and so we broke in. A cell phone was ringing on the hall table, and I — »