RISH DUNNE felt the familiar surge of adrenaline as she exited the bright lights of the Cube and moved into the raw darkness of the void. The SMSC’s front gate had just called to say that Katherine’s guest, Dr. Abaddon, had arrived and required an escort back to Pod 5. Trish had offered to bring him back, mostly out of curiosity. Katherine had said very little about the man who would be visiting them, and Trish was intrigued. The man was apparently someone Peter Solomon trusted deeply; the Solomons never invited anyone back to the Cube. This was a first.

I hope he handles the crossing okay, Trish thought as she moved through the frigid darkness. The last thing she needed was Katherine’s VIP panicking when he realized what he had to do to get to the lab. The first time is always the worst.

Trish’s first time had been about a year ago. She had accepted Katherine’s job offer, signed a nondisclosure, and then come to the SMSC with Katherine to see the lab. The two women had walked the length of “The Street,” arriving at a metal door marked POD 5. Even though Katherine had tried to prepare her by describing the lab’s remote location, Trish was not ready for what she saw when the pod door hissed open.

The void.

Katherine stepped over the threshold, walked a few feet into the perfect blackness, and then motioned for Trish to follow. “Trust me. You won’t get lost.”

Trish pictured herself wandering in a pitch-black, stadium-size room and broke a sweat at the mere thought.

“We have a guidance system to keep you on track.” Katherine pointed to the floor. “Very low-tech.”

Trish squinted through the darkness at the rough cement floor. It took a moment to see it in the darkness, but there was a narrow carpet runner that had been laid down in a straight line. The carpet ran like a roadway, disappearing into the darkness.

“See with your feet,” Katherine said, turning and walking off. “Just follow right behind me.”

As Katherine disappeared into the blackness, Trish swallowed her fear and followed. This is insane! She had taken only a few steps down the carpet when the Pod 5 door swung shut behind her, snuffing out the last faint hint of light. Pulse racing, Trish turned all of her attention to the feeling of the carpet beneath her feet. She had ventured only a handful of steps down the soft runner when she felt the side of her right foot hit hard cement. Startled, she instinctively corrected to the left, getting both feet back on soft carpet.

Katherine’s voice materialized up ahead in the blackness, her words almost entirely swallowed by the lifeless acoustics of this abyss. “The human body is amazing,” she said. “If you deprive it of one sensory input, the other senses take over, almost instantly. Right now, the nerves in your feet are literally ‘tuning’ themselves to become more sensitive.”

Good thing, Trish thought, correcting course again.

They walked in silence for what seemed entirely too long. “How much farther?” Trish finally asked.

“We’re about halfway.” Katherine’s voice sounded more distant now.

Trish sped up, doing her best to stay composed, but the breadth of the darkness felt like it would engulf her. I can’t see one millimeter in front of my face! “Katherine? How do you know when to stop walking?”

“You’ll know in a moment,” Katherine said.

That was a year ago, and now, tonight, Trish was once again in the void, heading in the opposite direction, out to the lobby to retrieve her boss’s guest. A sudden change in carpet texture beneath her feet alerted her that she was three yards from the exit. The warning track, as it was called by Peter Solomon, an avid baseball fan. Trish stopped short, pulled out her key card, and groped in the darkness along the wall until she found the raised slot and inserted her card.

The door hissed open.

Trish squinted into the welcoming light of the SMSC hallway.

Made it … again.

Moving through the deserted corridors, Trish found herself thinking about the bizarre redacted file they had found on a secure network. Ancient portal? Secret location underground? She wondered if Mark Zoubianis was having any luck figuring out where the mysterious document was located.

Inside the control room, Katherine stood in the soft glow of the plasma wall and gazed up at the enigmatic document they had uncovered. She had isolated her key phrases now and felt increasingly certain that the document was talking about the same far-flung legend that her brother had apparently shared with Dr. Abaddon.

I need to see the rest of the file, Katherine thought.

She stared a moment longer and then flipped the plasma wall’s power switch. Katherine always turned off this energy-intensive display so as not to waste the fuel cell’s liquid hydrogen reserves.

She watched as her keywords slowly faded, collapsing down into a tiny white dot, which hovered in the middle of the wall and then finally twinkled out.

She turned and walked back toward her office. Dr. Abaddon would be arriving momentarily, and she wanted to make him feel welcome.

LMOST THERE,” Anderson said, guiding Langdon and Sato down the seemingly endless corridor that ran the entire length of the Capitol’s eastern foundation. “In Lincoln’s day, this passage had a dirt floor and was filled with rats.”

Langdon felt grateful the floor had been tiled; he was not a big fan of rats. The group continued on, their footfalls drumming up an eerie, uneven echo in the long passageway. Doorways lined the long hallway, some closed but many ajar. Many of the rooms down on this level looked abandoned. Langdon noticed the numbers on the doors were now descending and, after a while, seemed to be running out.

SB4 … SB3 … SB2 … SB1 …

A TUNNEL BENEATH THE U.S. CAPITOL BUILDING

32.1: Courtesy of the author

They continued past an unmarked door, but Anderson stopped short when the numbers began ascending again.

HB1 … HB2 …

“Sorry,” Anderson said. “Missed it. I almost never come down this deep.”

The group backed up a few yards to an old metal door, which Langdon now realized was located at the hallway’s central point—the meridian that divided the Senate Basement (SB) and the House Basement (HB). As it turned out, the door was indeed marked, but its engraving was so faded, it was almost imperceptible.

“Here we are,” Anderson said. “Keys will be arriving any moment.”

Sato frowned and checked her watch.

Langdon eyed the SBB marking and asked Anderson, “Why is this space associated with the Senate side even though it’s in the middle?”

Anderson looked puzzled. “What do you mean?”

“It says SBB, which begins with an S, not an H.”

Anderson shook his head. “The S in SBB doesn’t stand for Senate. It—”

“Chief?” a guard called out in the distance. He came jogging up the hallway toward them, holding out a key. “Sorry, sir, it took a few minutes. We couldn’t locate the main SBB key. This is a spare from an auxiliary box.”

“The original is missing?” Anderson said, sounding surprised.

“Probably lost,” the guard replied, arriving out of breath. “Nobody has requested access down here for ages.”

Anderson took the key. “No secondary key for SBB Thirteen?”

“Sorry, so far we’re not finding keys for any of the rooms in the SBB. MacDonald’s on it now.” The guard pulled out his radio and spoke into it. “Bob? I’m with the chief. Any additional info yet on the key for SBB Thirteen?”

The guard’s radio crackled, and a voice replied, “Actually, yeah. It’s strange. I’m seeing no entries since we computerized, but the hard logs indicate all the storage rooms in the SBB were cleaned out and abandoned more than twenty years ago. They’re now listed as unused space.” He paused. “All except for SBB Thirteen.”

Anderson grabbed the radio. “This is the chief. What do you mean, all except SBB Thirteen?”

“Well, sir,” the voice replied, “I’ve got a handwritten notation here that designates SBB Thirteen as ‘private.’ It was a long time ago, but it’s written and initialed by the Architect himself.”

The term Architect, Langdon knew, was not a reference to the man who had designed the Capitol, but rather to the man who ran it. Similar to a building manager, the man appointed as Architect of the Capitol was in charge of everything including maintenance, restoration, security, hiring personnel, and assigning offices.

“The strange thing …” the voice on the radio said, “is that the Architect’s notation indicates that this ‘private space’ was set aside for the use of Peter Solomon.”

Langdon, Sato, and Anderson all exchanged startled looks.

“I’m guessing, sir,” the voice continued, “that Mr. Solomon has our primary key to the SBB as well as any keys to SBB Thirteen.”

Langdon could not believe his ears. Peter has a private room in the basement of the Capitol? He had always known Peter Solomon had secrets, but this was surprising even to Langdon.

“Okay,” Anderson said, clearly unamused. “We’re hoping to get access to SBB Thirteen specifically, so keep looking for a secondary key.”

“Will do, sir. We’re also working on the digital image that you requested—”

“Thank you,” Anderson interrupted, pressing the talk button and cutting him off. “That will be all. Send that file to Director Sato’s BlackBerry as soon as you have it.”

“Understood, sir.” The radio went silent.

Anderson handed the radio back to the guard in front of them.

The guard pulled out a photocopy of a blueprint and handed it to his chief. “Sir, the SBB is in gray, and we’ve notated with an X which room is SBB Thirteen, so it shouldn’t be hard to find. The area is quite small.”

Anderson thanked the guard and turned his focus to the blueprint as the young man hurried off. Langdon looked on, surprised to see the astonishing number of cubicles that made up the bizarre maze beneath the U.S. Capitol.

Anderson studied the blueprint for a moment, nodded, and then stuffed it into his pocket. Turning to the door marked SBB, he raised the key, but hesitated, looking uneasy about opening it. Langdon felt similar misgivings; he had no idea what was behind this door, but he was quite certain that whatever Solomon had hidden down here, he wanted to keep private. Very private.

Sato cleared her throat, and Anderson got the message. The chief took a deep breath, inserted the key, and tried to turn it. The key didn’t move. For a split second, Langdon felt hopeful the key was wrong. On the second try, though, the lock turned, and Anderson heaved the door open.

As the heavy door creaked outward, damp air rushed out into the corridor.

Langdon peered into the darkness but could see nothing at all.

“Professor,” Anderson said, glancing back at Langdon as he groped blindly for a light switch. “To answer your question, the S in SBB doesn’t stand for Senate. It stands for sub.“

“Sub?” Langdon asked, puzzled.

Anderson nodded and flicked the switch just inside the door. A single bulb illuminated an alarmingly steep staircase descending into inky blackness. “SBB is the Capitol’s subbasement.”

THE U.S. CAPITOL BUILDING