One of the perks of being U.S. ambassador, she thought. The wealthy Americans who owned what lay beyond this door had loaned Nagel a key, giving her access to this discreet backdoor entrance in hopes she would visit often, which she did.

  As they entered, Nagel wondered what Langdon would think if he knew where they were now headed. Behind this wall, in any of six candlelit chambers, the professor might find himself lying naked on a granite slab while robed attendants poured hot wax across his flesh.

  She has a key?

  If Langdon’s memory served, Prague’s famous Dripstone Wall had been erected against the rear facade of a thirteenth-century Augustine friary—the St. Thomas Monastery—meaning he had just stepped through the wall into ancient, hallowed hallways.

  Not so hallowed anymore, he mused.

  This grand monastery, like so many in Europe, had been repurposed to serve the needs of an increasingly secular world. In this case, it had been transformed into a Marriott Hotel—the Augustine Luxury. The monks’ ancient brewery was now reimagined as the ultrahip Refectory Bar, and the monastery’s original scriptorium had been preserved fully intact, complete with ancient texts, writing implements, and sharpening stones for quills.

  “As quietly as possible,” Nagel whispered, guiding them down a narrow passageway to a service door. When she pushed it open, Langdon found himself in an elegant hallway that smelled of tea tree, incense, and eucalyptus.

  “You brought us to a spa?” he asked as they arrived at a golden door, where a placard listed various treatments, including their specialty—the Monastic Ritual. He was no cloistral specialist, but he was fairly certain monastic rituals did not involve lavender body candles and collagen facials.

  “We’re safe here,” she whispered. “I know the staff, and the walls are soundproofed.”

  With that, Nagel motioned for them to wait as she slipped inside. Within a matter of seconds, she returned with a key fob and ushered them down the hall, where she unlocked one of the spa’s private, post-treatment salóneks.

  The windowless lounge had a faux-ecclesiastical feel with flickering electric candles, stained-glass art, and piped-in Gregorian chant. The soundtrack, Langdon noted, predated the monastery by four centuries. But anachronisms aside, he could imagine worse places to be. It’s private and warm. Better yet, Kerble had headed into the hotel to see if he could find them some food.

  “First off,” Nagel said, shedding her winter coat and motioning them to sit on the comfortable couches, “I can’t possibly imagine what you’ve both endured today. I’m relieved that you’re okay, and I realize we have a lot to discuss. But before we delve too deeply into it, I wanted to share some very good news.” She gave them both a tired smile. “As it turns out, the incriminating evidence that we were hoping to obtain about Threshold…We now have it.”

  How? Langdon wondered, imagining that all physical evidence of Threshold’s existence was pulverized and buried in rubble…along with, tragically, the most potent proof of all. Sasha Vesna herself.

  Nagel eyed them both, looking tired but energized. “As it turns out, we have a guardian angel. Stated more accurately, Sasha Vesna has a guardian angel.”

  Langdon was startled by the comment. He immediately pictured the cloaked figure who had declared himself Sasha’s protector and guardian. Does Nagel know about her split personality?

  “And her guardian angel,” she added, “sent me this.”

  Nagel produced a sheet of paper and laid it in front of them. When Katherine saw it, she let out a little gasp. Langdon felt a similar pall to read the handwritten message scrawled on a piece of cat-themed stationery.

  PLEASE HELP SASHA.

  My God, he thought, picturing Sasha’s hands writing these very words…a desperate call for help…an appeal that, strangely, Sasha knew nothing about.

  The ambassador quickly explained that the URL included in the message led to a tortured video confession in which Gessner divulged all she knew about Threshold—human testing, brain surgeries, implants, psychopharmaceuticals, near-death experiences, the list of people involved…all of it.

  “The video is very difficult to watch,” Nagel said, “but its existence means the CIA can never again come after you.”

  She let that sink in.

  “I’ve safeguarded a copy, and I intend to make backups. In short, no matter what else happens, this video is the only insurance you’ll ever need.” Her eyes flashed in the candlelight. “It’s your atomic bomb.”

  “Yours too, I hope,” Katherine said quietly.

  Nagel nodded. “Although I’m not sure how much we’ll need it. The director seemed as appalled as I was to learn some of the things that had gone on at Threshold.”

  “He had to know,” Langdon argued. “He’s the director.”

  “Yes, which is why he might not have known,” Nagel countered. “The agency is hypercompartmentalized on process—plausible deniability, autocratic efficiency. He put Finch in charge and therefore would have known only the details Finch chose to share.”

  Maybe, Langdon thought, maybe not. He picked up the letter, sensing the ambassador knew nothing of Sasha’s condition. “But why would Sasha’s guardian address this to you? Why not send the video directly to the press?”

  “In the video,” Nagel said, “Dr. Gessner admits that I knew almost nothing about Threshold’s true purpose and would be horrified by its existence. I suspect that admission is why Sasha’s guardian entrusted the video to me…imagining I was influential enough to help Sasha…or to make a difference. It goes without saying that if we ever locate Sasha, I am poised to help her in any way I can. She is a victim, and I did play a role in making Threshold a reality…despite being coerced and unaware.” She glanced away suddenly, staring into space. “But Michael Harris…” she whispered, almost tearfully, “what I forced him to do…spying on Sasha for Finch…It cost Michael his life.” Her eyes returned to them. “I will carry that guilt and shame forever.”

  Langdon wondered how Nagel would feel when she learned the complicated truth about Harris’s killer. The woman you ordered Harris to seduce was, in an odd sense, the one who murdered him.

  “Sasha’s protector,” Katherine said. “Her ‘guardian angel,’ as you put it. Did you ever learn his identity?”

  “Not conclusively,” Nagel replied. “He appeared only in glimpses in the video and was disguised, but I do have a strong suspicion I know who it was.”

  Langdon and Katherine exchanged a surprised glance.

  “The man on the video who tortured Gessner spoke with a Russian accent,” Nagel said. “And he told Gessner he was punishing her for betraying Sasha’s trust. But there was something about his rage that felt like personal betrayal…as if he too had been a Threshold test subject.”

  He was, Langdon thought. In a sense, he was patient number three. Langdon didn’t fully understand the complexities of DID, but it seemed that whatever procedures Gessner had carried out on Sasha could have been experienced by her alter, especially if that alter was protective and chose to endure those parts of Sasha’s life that were painful. According to Katherine, a dominant alter could govern which identity was conscious and in the forefront at any given moment.

  “The director informed me,” Nagel continued, “that Threshold’s first test subject was also Russian and was taken from the same institution as Sasha. His name was Dmitri Sysevich. Finch said he had died in the program, but the director said he had seen no proof of Dmitri’s death. It’s possible that Finch lied about it for some reason.”

  Finch didn’t lie, Langdon knew. Dmitri is dead. We saw his medical file.

  “Considering the video,” Nagel said, her tone regretful, “the director and I concluded that Dmitri Sysevich must have survived the program somehow and returned to take revenge.”

  In the uncomfortable silence, Langdon glanced at Katherine, their gazes locking. They both knew what needed to happen. It was time for the ambassador to learn the truth.

  “Ma’am,” Langdon said, turning back to her. “The person you saw killing Gessner…it was not Dmitri Sysevich.”

  CHAPTER 126

  Ambassador Nagel was uncertain how much time had passed when the group emerged through the Dripstone Wall. An hour? Two? Darkness had settled over Wallenstein Garden, and there seemed to be a cold foreboding in the shadows.

  She was still reeling from what Langdon had explained about Sasha, and while Nagel knew she would eventually be able to accept the truth intellectually…she feared there would be one fact that would forever cut through her emotions like a knife to the heart.

  Michael Harris was killed by…Sasha.

  “You have to remember,” Katherine insisted. “It was not Sasha who did this to Michael. She loved Michael. You must think of them as two people.”

  Either way, the news had caused her a fresh wave of crushing guilt. Nagel found herself wishing she could beg both Michael and Sasha for their forgiveness…but they were both gone.

  Even Wallenstein Garden seemed lifeless to her now, the rosebushes wrapped in burlap bags and the pond drained for winter. Nagel doubted she would witness its annual renaissance this spring. As of a few hours ago, she possessed enough political leverage to do whatever she wanted, which no longer included being a U.S. ambassador living in Prague.

  I was never supposed to be here, she thought. I was sent as a puppet.

  She would probably wait a month to help the embassy through the current crisis and then tender her resignation. She had no idea what she would do next, but she felt like she had some fight left in her…and a lot more to give.

  At the moment, her most immediate concern was recovering the USB stick that Scott Kerble had cleverly smuggled out of the embassy in the box of Dana’s belongings. Kerble would be headed to her flat shortly to recover it.

  As they exited the garden, Nagel glanced back at Langdon and Solomon, who were talking quietly as they followed. No doubt they both were deeply exhausted and needed sleep.

  “I’ll drive them back to their hotel,” Kerble said, as if reading her thoughts exactly. “Right after I drop you at the embassy.”

  They emerged into the glow of the streetlights, and Nagel knew she would miss Kerble most of all. “Scott,” she said softly. “I’m fully aware of the risks you took for me today…and I don’t take your loyalty for granted.”

  The Marine gave her a rare smile and touched his cap. “Nor I yours.”

  CHAPTER 127

  The most disturbing and effective piece of art in Europe, Langdon had long believed, was Victims of Communism—a memorial consisting of six life-size bronze men descending a wide concrete staircase. Each of the men was emaciated, bearded, and on a different step. Eerily, all six men were the same individual…but each was in a different state of decay…one missing an arm, another half his head, another with a gaping chasm through his chest.

  Defiance and endurance, Langdon recalled, was the artist’s message. This individual, regardless of his level of suffering, remained standing.

  Langdon had not anticipated seeing the sculpture on this visit to Prague, and yet there it was, rushing by the window of the embassy sedan as they sped along Újezd Street. He would have pointed it out to Katherine, but she was already asleep on his shoulder, her tousled hair soft against his cheek.

  Having dropped the ambassador at the embassy, Sergeant Kerble was now whisking Langdon and Katherine south along Petřín Gardens, headed for the Four Seasons Hotel and a much-needed rest. As they turned left onto Legion Bridge, Langdon closed his eyes and listened to Katherine’s soft breathing, feeling comforted by the reassuring sound of…life.

  The concept of death had been entirely too present today, not only in discussion, but also in Langdon’s reality…nearly freezing to death in the Vltava River, then being shot at by Pavel and narrowly escaping Threshold.

  Remarkably, over the past year, everything Langdon had learned from Katherine about consciousness had altered his perspective on dying…markedly easing his trepidation about aging and mortality. If Katherine’s nonlocal model of consciousness turned out to be correct, then the logical conclusion was that some part of Langdon, his being, his soul, his mind…would transcend the death of his body and live on.

  I’m in no hurry to find out, he thought, savoring the warmth of Katherine’s head on his shoulder.

  Yesterday, while touring the Vyšehrad, they had stumbled across an unusually morbid reliquary displaying a human shoulder blade—allegedly that of St. Valentine—and Katherine had startled him with a deceptively simple question: How do you define death?

  Having never considered death in literal terms, Langdon drew a blank, finally offering a feebly circular definition that he never would have accepted from his students: Death is the absence of life.

  To his surprise, Katherine told him his reply was quite close to the official, medical definition: The irreversible cessation of all cell function. Then she informed him that the official medical definition was 100 percent incorrect.

  “Death,” she explained, “has nothing to do with the physical body. We define death in terms of consciousness. Consider a brain-dead, nonresponsive patient on life support—his body is technically very much alive, and yet we routinely pull the plug on that body. Without consciousness, we view a human body as essentially dead…even when its physical functions are perfectly intact.”

  True, Langdon realized.

  “And the opposite is equally true,” she continued. “A quadriplegic in a wheelchair, who has lost physical function in his entire body and yet remains conscious, is very much alive. Stephen Hawking was essentially a mind without a body. Imagine if someone suggested pulling the plug on him!”

  Langdon had never heard the point made quite that way.

  “Robert,” she finished, “we can no longer deny the growing tide of evidence that consciousness can exist outside the body…beyond the confines of the brain. The day has come for us to entirely redefine consciousness…and therefore entirely redefine death!”

  Langdon hoped she was right, and that dying was not as “terminal” an event as most imagined. From the recesses of his memory, the ancient teachings of Asclepius bubbled up:

  Far too many fear death and regard it as the worst disaster that can befall them: they know nothing of what they speak. Death comes as a dissolution from an exhausted body…Just as the body leaves the mother’s womb when it is mature in it, so also does the soul leave the body when it has come to perfection.

  As a young student of comparative religion, Langdon had been amazed by the universality of the promise of reincarnation and life after death—the lone, unswerving assurance offered by every single religious tradition that had survived the test of time. He had always viewed this consistent trait as an example of Darwinian “survival of the fittest.” The only religions that survived were those offering a solution to humankind’s greatest fear.

  The more spiritual side of Langdon often wondered if perhaps the age-old promise of eternal life might actually predate religion…finding its roots in the lost wisdom of the ancients…a time when the human mind was sufficiently uncluttered to perceive the deepest truths that permeated the universe.

  A thought for another day, he decided as their car slowed in front of the Four Seasons.

  “Hey, sleepyhead,” he whispered to Katherine beside him. “We’re here.”

  Faukman lunged for the phone. “Hello?!”

  “Jonas, it’s Robert,” announced the unmistakable baritone voice. “I’m just back at the hotel. The manager said you’ve been calling nonstop.”

  “I have been!” Faukman exclaimed. “The explosion in Prague? I was worri—”

  “Sorry, we’re both okay.”

  Faukman sighed in relief. “You know, Robert, most authors make me nervous by submitting their manuscripts late, but you have an irritating habit—”

  “Thanks for your concern,” Langdon replied with a laugh, “but I was nowhere near the blast.”

  “Glad to hear it, even if I don’t believe it,” Faukman said. “I’ve witnessed your proclivity for proximity to peril.”

  “And I your predilection for paranoid presumptions.”

  Faukman chuckled. “That response was a bit too quick…even for you, Robert. How do I know this isn’t some AI chatbot?”

  “Because AI would never know you declined one of the bestselling novels of the past twenty years because you thought the author used too many ellipses.”

  “Hey! I told you that in confidence!”

  “Yes, and I’ll take it to my grave,” Langdon assured him. “Just not today.”

  “Any word on Katherine’s manuscript?” Faukman asked hopefully.

  “Sorry,” Langdon replied, his voice weary. “I wish I could give you better news…”

  It was just before seven o’clock when Langdon turned off the steam shower in the Royal Suite. The night was young, but a wintry darkness had long since settled over Prague, and he and Katherine had agreed they were headed directly to bed.

  Wrapping a towel around his waist, Langdon stepped from the shower and found Katherine submerged in a bubble bath with one lithe leg extended and a safety razor in her hand.

  She’s shaving her legs? he thought, surprised. “Are we going out?”

  Katherine laughed. “No, Robert, we are not going out. Do you really not know why a woman shaves her legs before bed?”

  “Ah…” He hesitated. “I just thought…you were exhausted.”

  “I was. But when I saw you get in the shower, I woke up.” She motioned to his toned abs. “You look pretty good, Aquaman…for someone your age.”

  “My age? You’re older than I am!”

  “Do you really want to go there?”

  “No, my darling…I do not.” Langdon walked over to the tub, sat on the edge, and placed a hand affectionately on the back of Katherine’s neck. “What I meant to say is you’re beautiful, brilliant, hilarious, and I adore you.” He kissed her softly on the lips. “And I’ll see you in bed.”