“My place.” He reached a gloved hand into an interior pocket of his vest and withdrew a sealed letter. “Take this to whatever captain you find there. I understand that someone is using my old lot to make repairs.”

Lucy was furious, but not stupid enough to put it on display. She said, “You could get anybody to carry a message for you. There’s no sense in sending me out into the streets, late at night, through crowds of hungry rotters just to get me out of the way. I’ll just leave, if that’s what you want, and if Briar says it’s all right with her.”

“Lucy.” He sighed as if she were truly tiring him with her protests. “You and I both know that you won’t set foot on any street this evening. If you haven’t figured out the fort block tunnels by now, then I’ve overestimated you for many years. Take the south fork at the third split, if you aren’t so certain. It’s marked in yellow. If you would rather not return all the way to your place in the Vaults, you may return here if you like—and we’ll have Richard set you up in the bronze wing.”

He presented the last sentence with a resounding vibe of dismissal. His hand was still holding the envelope with whatever instructions or requests for bribery it might contain.

Lucy glowered at his hand, and at his mask. She snatched the envelope and shot Briar a look that was too loaded to decipher.

Briar said, “Do it, if that’s how this works. I don’t mind, Lucy. I’ll be all right, and I’ll see you back at the Vaults in the morning.”

Minnericht did not agree with this claim, but he did not contradict it either, even though Lucy gave him time to do so.

“Good. If anything happens to her”—she indicated Briar—“we won’t be so easy to dismiss. You won’t be able to pretend we’re all friends here, not anymore.”

He replied, “I don’t care if we’re friends. And what makes you think anything untoward will happen to her? You won’t threaten me, not in my own home. Get out, if you’re going to make a nuisance of yourself.”

“Briar…” Lucy said. It was a plea and a warning.

Briar understood that the conversation was crowded with things she didn’t understand, and for which she had no context. She was missing something in the forced exchange, and whatever it was, it sounded dangerous. But she’d dug her own grave now, and she’d lie in it if she had to. She said, “It’s all right. I’ll see you in the morning.”

Lucy took a deep breath. The mechanisms in her clockwork arm gave a rattling patter as if they were straining. “I won’t leave you like this,” she said.

“Yes, you will,” Dr. Minnericht corrected her as he ushered her to the door and shoved her past its threshold.

She turned on her heel with rage in her eyes. “We’re not done here,” she said, but she left, letting the train door slam in her wake. From the other side, she shouted, “I’ll be back tonight!”

Dr. Minnericht said, “I wouldn’t recommend it,” but Lucy couldn’t hear him. Her retreating footsteps sounded like fury and humiliation.

Briar and Dr. Minnericht gave one another space, and the silence to think of a conversation safe enough to share. She said first, “About my son. I want you to tell me where he is, or how he is. I want to know if he’s alive.”

It was his turn to kick the subject ninety degrees without a transition. He said, “This isn’t the main body of the station, you know.”

“I realize that. We’re in a buried car, is all. I don’t know where you live down here, or what you do. I just want my boy.” She balled her hands into fists and unclenched them, using her hands to smooth her pockets instead. She wrapped one row of fingers around the strap of her satchel, as if feeling its weight and knowing what it held might give her some strength to stand her ground.

“Let me show you,” he said, but he didn’t clarify what he intended to share. He opened the train car door and held it for her like an ordinary gentleman.

She stepped outside and immediately twisted to face him, because she could not stand the thought of him walking behind her. Her mind was churning with reassurances and logic, and with all her heart she knew that this was not her husband, who was dead. But that didn’t change the way he walked, or the way he stood, or the way he watched her with polite scorn. She was dying to yank his helmet away and see his face, so that she could quiet the screamed warnings that distracted and harangued her. She was wishing with all her heart that he would say something—say anything—to either confirm or deny that he knew who she was and he intended to make use of that knowledge.

But no.

He led the way back into the corridor that ended in lights, and he guided her to another platform on pulleys. This platform was not like the rough-edged wood of the walkways outside; it was more carefully assembled, and designed with something like style.

Dr. Minnericht pulled a lever, and an ironwork gate slipped shut, closing them together inside a box as big as a closet. “Down one more level,” he explained. He reached for a handle overhead and tugged it.

A chain unspooled, and the lift began to drop, settling on the floor below only seconds later.

On the other side of the ironwork gate, which slid aside with a thunderous rattle, Briar found a place like a ballroom—all gleaming and gold, with floors as bright as mirrors and chandeliers that hung from the ceiling like crystalline puppets.

She found her breath, and said, “Lucy told me this place was nicer than the Vaults. She wasn’t kidding.”

“Lucy wouldn’t know about this level,” he said. “I’ve never taken her here. And this is not our destination—it’s only a place we’re passing through.”

Briar walked under the glittering lights and they seemed to turn as if to follow her—and they weren’t crystals, they were glass bulbs and tubes, laced together with wires and gears. She tried not to stare, but failed. “Where did those come from? They’re… they… they’re amazing.” She wanted badly to say that they reminded her of something else, but she couldn’t confess it.

As the light tinkled down in shattered rays, sweeping the floor with white patterns that said strange things to the shadows, Briar remembered a mobile Levi had made when they’d talked about a baby.

She hadn’t known about Zeke when the Boneshaker had ravaged the city. She hadn’t yet suspected, but they’d planned.

And he’d made a lighted fixture—so clever and so sparkling that although she was no infant herself, she’d been fascinated with the trinket. She’d hung it in a corner of the parlor, intending to use it as a lamp until they had a nursery to put it in, though the nursery never happened.

But these lights were much larger, big enough to fill a bed. They would never fit in a corner or over a crib. Still, she couldn’t deny that the design was similar enough to startle her.

Minnericht saw her looking and said, “The first one is there.” He nodded up at the center light, the biggest of the assortment. “It had been shipped to the station for use in the main terminal. You can see, it’s not like the rest. I found it on a car, boxed and covered in earth like everything else on the south quadrant of the city. The rest of them took some assembling.”

“I bet,” she said. It was too much, this familiarity. It was too strange, the way he rambled the same way about the things that pleased him.

“It’s an experiment, I admit. Those two over there are powered by kerosene, but it’s a bit of a mess and they smell more strongly than could be called pleasant. The two on the right are run by electricity, which I think might prove the better option. But it’s tricky, and it can be just as dangerous as fire.”

“Where are you taking me?” she asked, as much to break the spell of his mellow enthusiasm as from a desire to know.

“To a place where we can talk.”

“We can talk right here.”

He leaned his head in a mimed shrug and said, “True, but there’s nowhere to sit, and I’d prefer to be comfortable. Wouldn’t you prefer to be comfortable?”

“Yes,” she said, though she knew it wasn’t going to happen.

It did not matter that he’d shifted back into the civilized personality that had slipped when she’d confronted him. Briar knew what waited on the other side of his social warmth, and it was marked with a black hand. It smelled like death, and it moaned for the flesh of the living; and she was not swayed by any of it.

Finally they came to a carved wooden door that was too dark to be stained and too ornate to be merely a piece of salvage. Made from ebony that grew the color of coffee, the door was marked with scenes from a war, and with soldiers in costumes that might have been Greek or Roman.

It would have taken Briar time to decipher the decoration fully, and Minnericht did not give her any time.

He whisked her past the door and into a room with a carpet thicker than oatmeal, but about the same color. A desk made from some lighter wood than the door hulked in front of a fireplace that looked like nothing Briar had ever seen before. It was made of glass and brick, with clear pipes that bubbled with boiling water, burbling like a creek and warming the room without any smoke or ash.

A round, red settee with plush dimples sat in front of the desk, at an angle; and an overstuffed armchair lurked beside it. “Pick one,” Minnericht invited.

She picked the armchair.

It swallowed her with squeaky, slick leather and brass rivets.

He took a seat behind the desk, assuming authority as if it were his birthright. He folded his hands together and rested them on the top of the table.

Briar felt herself getting hot, starting with the spots behind her ears. She knew without looking that she was flushing, and that the dark pink was blossoming down her neck and across her breasts. She was glad for her coat and her high-collared shirt. At least he could only see the color in her cheeks, and he might assume that she was merely warm.

Behind the doctor, the bright tube fireplace hummed and gurgled, occasionally spitting small burps of steam.