Langdon laughed. “I need to learn about the severing of these horses’ heads for transport during the Crusades.”

Ettore Vio looked as if Langdon had just inquired about the Queen’s hemorrhoids. “Heavens, Robert,” he whispered, “we don’t speak of that. If you want to see severed heads, I can show you the famed decapitated Carmagnola or—”

“Ettore, I need to know which Venetian doge cut off these heads.”

“It never happened,” Ettore countered defensively. “I’ve heard the tales, of course, but historically there is little to suggest that any doge committed—”

“Ettore, please, humor me,” Langdon said. “According to the tale, which doge was it?”

Ettore put on his glasses and eyed Langdon. “Well, according to the tale, our beloved horses were transported by Venice’s most clever and deceitful doge.”

“Deceitful?”

“Yes, the doge who tricked everyone into the Crusades.” He eyed Langdon expectantly. “The doge who took state money to sail to Egypt … but redirected his troops and sacked Constantinople instead.”

Sounds like treachery, Langdon mused. “And what was his name?”

Ettore frowned. “Robert, I thought you were a student of world history.”

“Yes, but the world is large, and history is long. I could use some help.”

“Very well then, a final clue.”

Langdon was going to protest, but he sensed that he’d be wasting his breath.

“Your doge lived for nearly a century,” Ettore said. “A miracle in his day. Superstition attributed his longevity to his brave act of rescuing the bones of Saint Lucia from Constantinople and bringing them back to Venice. Saint Lucia lost her eyes to—”

“He plucked up the bones of the blind!” Sienna blurted, glancing at Langdon, who had just had the same thought.

Ettore gave Sienna an odd look. “In a manner of speaking, I suppose.”

Ferris looked suddenly wan, as if he had not yet caught his breath from the long walk across the plaza and the climb up the stairs.

“I should add,” Ettore said, “that the doge loved Saint Lucia so much because the doge himself was blind. At the age of ninety, he stood out in this very square, unable to see a thing, and preached the Crusade.”

“I know who it is,” Langdon said.

“Well, I should hope so!” Ettore replied with a smile.

Because his eidetic memory was better suited to images rather than uncontextualized ideas, Langdon’s revelation had arrived in the form of a piece of artwork—a famous illustration by Gustave Doré depicting a wizened, blind doge, arms raised high overhead as he incited a gathered crowd to join the Crusade. The name of Doré’s illustration was clear in his mind: Dandolo Preaching the Crusade.

“Enrico Dandolo,” Langdon declared. “The doge who lived forever.”

“Finalmente!” Ettore said. “I fear your mind has aged, my friend.”

“Along with the rest of me. Is he buried here?”

“Dandolo?” Ettore shook his head. “No, not here.”

“Where?” Sienna demanded. “At the Doge’s Palace?”

Ettore took off his glasses, thinking a moment. “Give me a moment. There are so many doges, I can’t recall—”

Before Ettore could finish, a frightened-looking docent came running over and ushered him aside, whispering in his ear. Ettore stiffened, looking alarmed, and immediately hurried over to a railing, where he peered down into the sanctuary below. After a moment he turned back toward Langdon.

“I’ll be right back,” Ettore shouted, and then hurried off without another word.

Puzzled, Langdon went over to the railing and peered over. What’s going on down there?

At first he saw nothing at all, just tourists milling around. After a moment, though, he realized that many of the visitors were staring in the same direction, toward the main entrance, through which an imposing group of black-clad soldiers had just entered the church and was fanning out across the narthex, blocking all the exits.

The soldiers in black. Langdon felt his hands tighten on the railing.

“Robert!” Sienna called out behind him.

Langdon remained fixated on the soldiers. How did they find us?!

“Robert,” she called more urgently. “Something’s wrong! Help me!”

Langdon turned from the railing, puzzled by her cries for help.

Where did she go?

An instant later, his eyes found both Sienna and Ferris. On the floor in front of the Horses of St. Mark’s, Sienna was kneeling over Dr. Ferris … who had collapsed in convulsions, clutching his chest.

CHAPTER 75

“I think he’s having a heart attack!” Sienna shouted.

Langdon hurried over to where Dr. Ferris lay sprawled on the floor.

The man was gasping, unable to catch his breath.

What happened to him?! For Langdon, everything had come to a head in a single moment. With the soldiers’ arrival downstairs and Ferris thrashing on the floor, Langdon felt momentarily paralyzed, unsure which way to turn.

Sienna crouched down over Ferris and loosened his necktie, tearing open the top few buttons of his shirt to help him breathe. But as the man’s shirt parted, Sienna recoiled and let out a sharp cry of alarm, covering her mouth as she staggered backward, staring down at the bare flesh of his chest.

Langdon saw it, too.

The skin of Ferris’s chest was deeply discolored. An ominous-looking bluish-black blemish the circumference of a grapefruit spread out across his sternum. Ferris looked like he’d been hit in the chest with a cannonball.

“That’s internal bleeding,” Sienna said, glancing up at Langdon with a look of shock. “No wonder he’s been having trouble breathing all day.”

Ferris twisted his head, clearly trying to speak, but he could only make faint wheezing sounds. Tourists had started gathering around, and Langdon sensed that the situation was about to get chaotic.

“The soldiers are downstairs,” Langdon warned Sienna. “I don’t know how they found us.”

The look of surprise and fear on Sienna’s face turned quickly to anger, and she glared back down at Ferris. “You’ve been lying to us, haven’t you?”

Ferris attempted to speak again, but he could barely make a sound. Sienna roughly searched Ferris’s pockets and pulled out his wallet and phone, which she slipped into her own pocket, standing over him now with an accusatory glower.

At that moment an elderly Italian woman pushed through the crowd, shouting angrily at Sienna. “L’hai colpito al petto!” She made a forceful motion with her fist against her own chest.

“No!” Sienna snapped. “CPR will kill him! Look at his chest!” She turned to Langdon. “Robert, we need to get out of here. Now.”

Langdon looked down at Ferris, who desperately locked eyes with him, pleading, as if he wanted to communicate something.

“We can’t just leave him!” Langdon said frantically.

“Trust me,” Sienna said. “That’s not a heart attack. And we’re leaving. Now.”

As the crowd closed in, tourists began shouting for help. Sienna gripped Langdon’s arm with startling force and dragged him away from the chaos, out into the fresh air of the balcony.

For a moment Langdon was blinded. The sun was directly in front of his eyes, sinking low over the western end of St. Mark’s Square, bathing the entire balcony in a golden light. Sienna led Langdon to their left along the second-story terrace, snaking through the tourists who had stepped outside to admire the piazza and the replicas of the Horses of St. Mark’s.

As they rushed along the front of the basilica, the lagoon was straight ahead. Out on the water, a strange silhouette caught Langdon’s eye—an ultramodern yacht that looked like some kind of futuristic warship.

Before he could give it a second thought, he and Sienna had cut left again, following the balcony around the southwest corner of the basilica toward the “Paper Door”—the annex connecting the basilica to the Doge’s Palace—so named because the doges posted decrees there for the public to read.

Not a heart attack? The image of Ferris’s black-and-blue chest was imprinted in Langdon’s mind, and he suddenly felt fearful at the prospect of hearing Sienna’s diagnosis of the man’s actual illness. Moreover, it seemed something had shifted, and Sienna no longer trusted Ferris. Was that why she was trying to catch my eye earlier?

Sienna suddenly skidded to a stop and leaned out over the elegant balustrade, peering down into a cloistered corner of St. Mark’s Square far below.

“Damn it,” she said. “We’re higher up than I thought.”

Langdon stared at her. You were thinking of jumping?!

Sienna looked frightened. “We can’t let them catch us, Robert.”

Langdon turned back toward the basilica, eyeing the heavy door of wrought iron and glass directly behind them. Tourists were entering and exiting, and if Langdon’s estimate was correct, passing through the door would deposit them back inside the museum near the back of the church.

“They’ll have all the exits covered,” Sienna said.

Langdon considered their escape options and arrived at only one. “I think I saw something inside that could solve that problem.”

Barely able to fathom what he was even now considering, Langdon guided Sienna back inside the basilica. They skirted the perimeter of the museum, trying to stay out of sight among the crowd, many of whom were now looking diagonally across the vast open space of the central nave toward the commotion going on around Ferris. Langdon spied the angry old Italian woman directing a pair of black-clad soldiers out onto the balcony, revealing Langdon and Sienna’s escape route.

We’ll have to hurry, Langdon thought, scanning the walls and finally spotting what he was looking for near a large display of tapestries.

The device on the wall was bright yellow with a red warning sticker: ALLARME ANTINCENDIO.

“A fire alarm?” Sienna said. “That’s your plan?”

“We can slip out with the crowd.” Langdon reached up and grabbed the alarm lever. Here goes nothing. Acting quickly before he could think better of it, he pulled down hard, seeing the mechanism cleanly shatter the small glass cylinder inside.

The sirens and pandemonium that Langdon expected never came.

Only silence.

He pulled again.

Nothing.

Sienna stared at him like he was crazy. “Robert, we’re in a stone cathedral packed with tourists! You think these public fire alarms are active when a single prankster could—”

“Of course! Fire laws in the U.S.—”

“You’re in Europe. We have fewer lawyers.” She pointed over Langdon’s shoulder. “And we’re also out of time.”

Langdon turned toward the glass door through which they’d just entered and saw two soldiers hurrying in from the balcony, their hard eyes scanning the area. Langdon recognized one as the same muscular agent who had fired at them on the Trike as they were fleeing Sienna’s apartment.

With precious few options, Langdon and Sienna slipped out of sight in an enclosed spiral stairwell, descending back to the ground floor. When they reached the landing, they paused in the shadows of the stairwell. Across the sanctuary, several soldiers stood guarding the exits, their eyes intently sweeping the entire room.

“If we step out of this stairwell, they’ll see us,” Langdon said.

“The stairs go farther down,” Sienna whispered, motioning to an ACCESSO VIETATO swag that cordoned off the stairs beneath them. Beyond the swag, the stairs descended in an even tighter spiral toward pitch blackness.

Bad idea, Langdon thought. Subterranean crypt with no exit.

Sienna had already stepped over the swag and was groping her way down the spiral tunnel, disappearing into the void.

“It’s open,” Sienna whispered from below.

Langdon was not surprised. The crypt of St. Mark’s was different from many other such places in that it was also a working chapel, where regular services were held in the presence of the bones of St. Mark.

“I think I see natural light!” Sienna whispered.

How is that possible? Langdon tried to recall his previous visits to this sacred underground space and guessed that Sienna was probably seeing the lux eterna—an electric light that remained lit on St. Mark’s tomb in the center of the crypt. With footsteps approaching from above him, though, Langdon didn’t have time to think. He quickly stepped over the swag, making sure he didn’t move it, and then he placed his palm on the rough-hewn stone wall, feeling his way down around the curve and out of sight.

Sienna was waiting for him at the bottom of the stairs. Behind her, the crypt was barely visible in the darkness. It was a squat subterranean chamber with an alarmingly low stone ceiling supported by ancient pillars and brick-vaulted archways. The weight of the entire basilica rests on these pillars, Langdon thought, already feeling claustrophobic.

“Told you,” Sienna whispered, her pretty face faintly illuminated by the hint of muted natural light. She pointed to several small, arched transoms, high on the wall.

Light wells, Langdon realized, having forgotten they were here. The wells—designed to bring light and fresh air into this cramped crypt—opened into deep shafts that dropped down from St. Mark’s Square above. The window glass was reinforced with a tight ironwork pattern of fifteen interlocking circles, and although Langdon suspected that they could be opened from inside, they were shoulder height and would be a tight fit. Even if they somehow managed to get through the window into the shaft, climbing out of the shafts would be impossible, since they were ten feet deep and covered by heavy security grates at the top.

In the dim light that filtered through the wells, St. Mark’s crypt resembled a moonlit forest—a dense grove of trunklike pillars that cast long and heavy-looking shadows across the ground. Langdon turned his gaze to the center of the crypt, where a lone light burned at St. Mark’s tomb. The basilica’s namesake rested in a stone sarcophagus behind an altar, before which there were lines of pews for those lucky few invited to worship here at the heart of Venetian Christendom.