hy isn’t Peter answering? Katherine Solomon wondered as she hung up her cell phone. Where is he?

For three years, Peter Solomon had always been the first to arrive for their weekly seven P.M. Sunday-night meetings. It was their private family ritual, a way to remain connected before the start of a new week, and for Peter to stay up-to-date on Katherine’s work at the lab.

He’s never late, she thought, and he always answers his phone. To make matters worse, Katherine was still not sure what she was going to say to him when he did finally arrive. How do I even begin to ask him about what I found out today?

Her footsteps clicked rhythmically down the cement corridor that ran like a spine through the SMSC. Known as “The Street,” the corridor connected the building’s five massive storage pods. Forty feet overhead, a circulatory system of orange ductwork throbbed with the heartbeat of the building—the pulsing sounds of thousands of cubic feet of filtered air being circulated.

Normally, during her nearly quarter-mile walk to her lab, Katherine felt calmed by the breathing sounds of the building. Tonight, however, the pulsing had her on edge. What she had learned about her brother today would have troubled anyone, and yet because Peter was the only family she had in the world, Katherine felt especially disturbed to think he might be keeping secrets from her.

As far as she knew, he had kept a secret from her only once . . . a wonderful secret that was hidden at the end of this very hallway. Three years ago, her brother had walked Katherine down this corridor, introducing her to the SMSC by proudly showing off some of the building’s more unusual items—the Mars meteorite ALH-84001, the handwritten pictographic diary of Sitting Bull, a collection of wax-sealed Ball jars containing original specimens collected by Charles Darwin.

At one point, they walked past a heavy door with a small window. Katherine caught a glimpse of what lay beyond and gasped. “What in the world is that?!”

Her brother chuckled and kept walking. “Pod Three. It’s called Wet Pod. Pretty unusual sight, isn’t it?”

Terrifying is more like it. Katherine hurried after him. This building was like another planet.

“What I really want to show you is in Pod Five,” her brother said, guiding her down the seemingly endless corridor. “It’s our newest addition. It was built to house artifacts from the basement of the National Museum of Natural History. That collection is scheduled for relocation here in about five years, which means Pod Five is sitting empty at the moment.”

Katherine glanced over. “Empty? So why are we looking at it?”

Her brother’s gray eyes flashed a familiar mischief. “It occurred to me that because nobody is using the space, maybe you could use it.”

“Me?”

“Sure. I thought maybe you could use a dedicated lab space—a facility where you can actually perform some of the theoretical experiments you’ve been developing for all these years.”

Katherine stared at her brother in shock. “But, Peter, those experiments are theoretical! To actually perform them would be almost impossible.”

“Nothing is impossible, Katherine, and this building is perfect for you. The SMSC is not just a warehouse of treasures; it’s one of the world’s most advanced scientific research facilities. We’re constantly taking pieces from the collection and examining them with the best quantitative technologies money can buy. All the equipment you could possibly need would be here at your disposal.”

“Peter, the technologies required to run these experiments are—”

“Already in place.” He smiled broadly. “The lab is done.”

Katherine stopped short.

Her brother pointed down the long corridor. “We’re going to see it now.”

Katherine could barely speak. “You . . . you built me a lab?”

“It’s my job. The Smithsonian was established to advance scientific knowledge. As secretary, I must take that charge seriously. I believe the experiments you’ve proposed have the potential to push the boundaries of science into uncharted territory.” Peter stopped and looked her squarely in the eyes. “Whether or not you were my sister, I would feel obliged to support this research. Your ideas are brilliant. The world deserves to see where they lead.”

“Peter, I can’t possibly—”

“Okay, relax . . . it was my own money, and nobody’s using Pod Five right now. When you’re done with your experiments, you’ll move out. Besides, Pod Five has some unique properties that will be perfect for your work.”

Katherine could not imagine what a massive, empty pod might offer that would serve her research, but she sensed she was about to find out. They had just reached a steel door with boldly stenciled letters:

POD 5

Her brother inserted his key card into a slot and an electronic keypad lit up. He raised his finger to type his access code, but paused, arching his eyebrows in the same mischievous way he always had as a boy. “You sure you’re ready?”

She nodded. My brother, always the showman.

“Stand back.” Peter hit the keys.

The steel door hissed loudly open.

Beyond the threshold was only inky blackness . . . a yawning void. A hollow moan seemed to echo out of the depths. Katherine felt a cold blast of air emanating from within. It was like staring into the Grand Canyon at night.

“Picture an empty airline hangar waiting for a fleet of Airbuses,” her brother said, “and you get the basic idea.”

Katherine felt herself take a step backward.

“The pod itself is far too voluminous to be heated, but your lab is a thermally insulated cinder-block room, roughly a cube, located in the farthest corner of the pod for maximum separation.”

Katherine tried to picture it. A box inside a box. She strained to see into the darkness, but it was absolute. “How far back?”

“Pretty far . . . a football field would fit easily in here. I should warn you, though, the walk is a little unnerving. It’s exceptionally dark.”

Katherine peered tentatively around the corner. “No light switch?”

“Pod Five is not yet wired for electricity.”

“But . . . then how can a lab function?”

He winked. “Hydrogen fuel cell.”

Katherine’s jaw dropped. “You’re kidding, right?”

“Enough clean power to run a small town. Your lab enjoys full radio-frequency separation from the rest of the building. What’s more, all pod exteriors are sealed with photo-resistant membranes to protect the artifacts inside from solar radiation. Essentially, this pod is a sealed, energy-neutral environment.”

Katherine was starting to comprehend the appeal of Pod 5. Because much of her work centered on quantifying previously unknown energy fields, her experiments needed to be performed in a location isolated from any extraneous radiation or “white noise.” This included interference as subtle as “brain radiation” or “thought emissions” generated by people nearby. For this reason, a university campus or hospital lab wouldn’t work, but a deserted pod at the SMSC could not have been more perfect.

“Let’s go back and have a look.” Her brother was grinning as he stepped into the vast darkness. “Just follow me.”

Katherine stalled at the threshold. Over a hundred yards in total darkness? She wanted to suggest a flashlight, but her brother had already disappeared into the abyss.

“Peter?” she called.

“Leap of faith,” he called back, his voice already fading away. “You’ll find your way. Trust me.”

He’s kidding, right? Katherine’s heart was pounding as she stepped a few feet over the threshold, trying to peer into the darkness. I can’t see a thing! Suddenly the steel door hissed and slammed shut behind her, plunging her into total blackness. Not a speck of light anywhere. “Peter?!”

Silence.

You’ll find your way. Trust me.

Tentative, she inched forward blindly. Leap of faith? Katherine could not even see her hand directly in front of her face. She kept moving forward, but within a matter of seconds, she was entirely lost. Where am I going?

That was three years ago.

Now, as Katherine arrived at the same heavy metal door, she realized how far she had come since that first night. Her lab—nicknamed the Cube—had become her home, a sanctuary within the depths of Pod 5. Exactly as her brother had predicted, she had found her way through the darkness that night, and every day since—thanks to an ingeniously simple guidance system that her brother had let her discover for herself.

Far more important, her brother’s other prediction had come true as well: Katherine’s experiments had produced astonishing results, particularly in the last six months, breakthroughs that would alter entire paradigms of thinking. Katherine and her brother had agreed to keep her results absolutely secret until the implications were more fully understood. One day soon, however, Katherine knew she would publish some of the most transformative scientific revelations in human history.

A secret lab in a secret museum, she thought, inserting her key card into the Pod 5 door. The keypad lit up, and Katherine typed her PIN.

The steel door hissed open.

The familiar hollow moan was accompanied by the same blast of cold air. As always, Katherine felt her pulse rate start to climb.

Strangest commute on earth.

Steeling herself for the journey, Katherine Solomon glanced at her watch as she stepped into the void. Tonight, however, a troubled thought followed her inside. Where is Peter?