Gray pulled out the silver crucifix from around his neck. Friar Agreer's cross. He tested its dimensions and shape against the inscription on the tile. A perfect fit.

"You found it," Vigor said.

Balthazar already had a small rubber mallet in hand, removed from his belt. He tapped at the tile. Gray's brow pinched at the man's deliberate work.

Vigor explained, "It was how we found the hollow spot beneath the inscribed tile in the Tower of Winds. Percussion. Listening for any hidden cavity."

Balthazar worked across the tile, meticulous, but the furrows across his forehead deepened. "Nothing," he finally mumbled.

"Are you sure?" Vigor said. "It has to be here."

"No," Gray said. He sprawled out on his back, staring up. "What's Jesus staring at?"

Vigor glanced to the vague figure of Christ in silver on the crucifix, then back up.

"He's staring at the dome," Gray answered. "The same dome that transfixed Marco Polo. A dome lightened in weight through the use of hollow bricks. If you wanted to hide something that would last the ages . . ."

Vigor craned, mouth wide. "Of course. But which brick?"

Balthazar leaped to his feet. "I have an idea." He ran off toward the rear of the building, shoving through a German tour group.

Vigor offered a hand and helped Gray back to his feet. Gray collected the cross and hung it back around his neck.

"Brilliant, Gray."

"We haven't found the second golden paitzu yet."

Vigor knew Gray had pulled Seichan aside for a private few words before they separated. "What's the urgency, Gray? With Nasser coming in a few hours, why even bother finding the second key?"

"Because I want Nasser happy," Gray said. Vigor read the worry in the young man's eyes for his parents. "And to prove our use to him. We need him to keep us alive."

Vigor sensed the man was leaving some bit of the plot unspoken. Before he could question Gray further, Balthazar reappeared and hurried back to them. Breathless, he held out a small tool. "With all the construction going on, I figured someone had to have a laser pointer or level. Handy when working across such vast spaces."

Vigor's colleague knelt down and positioned the laser device atop the inscribed cross and switched it on. Nothing seemed to happen.

Balthazar picked up a pinch of plaster dust and cast it above the device. A scintillation of ruby brilliance lit up the dust. "It's working." He craned up. "Someone will have to climb up the scaffolding to find which brick is lit up by the pointer."

Gray nodded. "I'll do it."

Balthazar glanced around guiltily—then handed him a chisel and hammer. "I got these, too." He waved for Gray to hide the tools away. "You'll have to be discreet. No one's allowed up there without a special artisan's pass issued by the Turkish government. I got permission from the curator to allow one of us up there. To take some photographs. Briefly. But the guard"—he nodded to the armed sentinel by the scaffolding's ladder—"in this day of terrorist attacks, they've been trained to shoot and ask questions later. If they see you take a chisel to the roof. . ." His voice trailed off.

"Beyond getting shot," Vigor warned, "we can't be discovered in any regard. If we're kicked out. . . if the police are summoned .. ."

Vigor read the understanding in Gray's eyes.

Nasser would know.

"And it's not just our lives in jeopardy," Vigor acknowledged.

Gray's parents would suffer, too.

Sighing deeply, Gray lowered his voice, "Then we'll need a distraction."

11:48 A.M.

Halfway up the scaffolding, Gray kept his head ducked from the low bracings as he climbed. Reaching a landing of planks, he glanced below and spotted Balthazar. The tall man's features were barely discernible as he stood with the museum curator. Gray leaned out to spot the scaffolding's guard. The uniformed man had stepped away from his station to get a clear view of Gray's progress.

Under everyone's watchful gaze, Gray continued onward. He reached the ring of windows along the bottom edge of the dome. Sunlight blazed through the arched glass. Gray caught a glimpse of the Sea of Marmara through one of them. Then he was above the windows. The way grew more shadowy. After another two minutes of scaling, he finally reached the top of the scaffolding and could touch the domed roof. In fact, he had to crouch to keep from hitting his head.

All around, vast scripts of Islamic calligraphy cascaded down the scalloped walls. Immediately overhead, the dome's central vertex cupped an ornate spiral of gold Arabic lettering, painted against a rich purple backdrop.

Gray searched around the edge of the vertex. Small dust motes flickered with fire to the left, lit from below by the laser pointer. He spotted his target—a glowing ruby dot sighted on a deep purple section of plaster. Good. The color was dark enough that any hole in it should be hard to spot.

At least he hoped so.

Reaching the targeted brick required continuing on hands and knees as the domed roof arched downward.

Once there, Gray crouched up and felt across the plaster. There was no carving. No angelic script. No other marking.

He frowned. What if he was wrong?

Unfortunately, there was only one way to find out. Gray waved his hand across the path of the laser, lighting up his hand.

It was the signal.

Below, Balthazar bent down, casually collected up the pointer, and aimed it down the length of the cavernous nave.

As if the light had struck some gong, a loud police whistle blew from that end of the church, piercing the solemn quiet, echoing all around the interior. Confused shouts followed.

Gray stared in the direction and spotted a burst of flame. An improvised Molotov cocktail, derived from rubbing alcohol used to clean the mosaics. Vigor had set it off in a trash receptacle.

More shouts.

Gray swung around to keep the bulk of his form between the guard below and his desecration above. He lifted his tools from his belt, positioned the chisel tip where the pointer had been. He waited a tense breath, then a second whistle blew.

As it blasted, Gray struck one strong blow.

Plaster broke—along with the hollow crack of dry clay.

A chunk of brick shattered free, struck Gray's chest, and bounced off. He snapped out a hand and caught the lump in the hand with the chisel before it could tumble to the marble floor below. Cringing internally, Gray shoved the broken shard into his shirt.

Using the chisel, he quickly levered into the heart of the hollow brick, careful of the loosened pieces. Reaching up, he examined the cavity with his fingers. Rather than course clay, it felt glassy inside, watery smooth. He searched around.

Something was up there.

He fingered it out. Gray had been expecting the golden paitzu, but instead he pulled out an eight-inch-long tube of copper or bronze, capped at both ends, not unlike a cigar holder. The object ended up down his shirt.

Casting a sidelong glance, Gray noted the small trash fire had already been smothered with an extinguisher.

Hurrying, he searched again and felt something heavy, nudged with his index finger. It took another few seconds to work the second prize out of the secret vault: another gold paitzu.

The heavy passport fell free, bobbled out of his frantic fingers, and clattered to the rungs of the scaffolding at his feet. The metal rang like a struck bell, amplified by the cup of the dome. Unfortunately, it hit at the exact moment when there was a lull in the commotion below.

Crap . . .

As the noise echoed away, Gray grabbed up the golden passport and tucked it into his shirt. With shouts calling up from below, he did the only thing he could. He kicked the hammer off the scaffolding and tumbled after it, arms wheeling in midair, a shout on his lips.

11:58 A.M.

From the second-floor colonnade Vigor watched Gray plummet off the top of the scaffolding.

Oh, no . . .

Moments before, Vigor had blown the whistle at the opposite end of the church and dropped the lit Molotov he had been holding, hidden inside an unattended trash receptacle. He barely got his arm out in time, hurrying away. He had blown the whistle again—then tossed it into a potted plant. Having already donned the Roman collar of his profession, he merely had to look confused and a little scared. The guards ignored him as he rushed the length of the upper floor back toward the central nave.

He reached the center of the church in time to hear Gray shout and fall headlong off the immense scaffolding. People came running, others scattered out of the way below. A hammer struck the marble floor with a resounding crack.

Overhead, Gray cartwheeled and snagged a strut of the scaffolding with an outstretched hand. He slammed back into the bracings. His feet kicked and struggled for a purchase. He found it and scrambled back into the heart of the scaffolding. He lay on his back, plainly collecting his wits from the fall.

The scaffolding guard yelled up at him and waved another security guard to pound up the stairs to check on him.

Gray rolled back and forth, clutching his left arm, moaning.

Vigor circled back to the stairs to reach the floor of the nave. He joined Balthazar and the museum curator. The security guard helped Gray up, and half supported by the guard, the pair descended with care.

As Gray limped along, his face purpled with anger. He pointed to the hammer, the very hammer Balthazar had given him. "Don't your workmen clean up after themselves," he sputtered in frightened outrage. "All that commotion down here, I accidentally stepped on the blasted tool. 1 could have been killed!"

The curator, a slender man with a bit of a paunch, collected the hammer. "Oh, my dear sir, my apologies. Such recklessness. I assure you. It will be attended. Your arm . . ."

Gray was holding it to his chest. "Sprained, maybe dislocated." He glowered at the curator.

"The police are already on their way here ... for the fire," the curator said.

Gray and Vigor shared a worried look.

If Nasser heard the police had come here. . .

Vigor cleared his throat. "The fire. Surely it was just a cigarette tossed by a careless tourist. Or maybe a harmless prank."