Upon reaching a sealed door, he pulled out the lever and gave it a tug. The door squeaked, and the rubber flaps surrounding its edges protested. They dragged it along the ground with a scraping, sucking noise. On the other side of that door, a second sealed door waited.

Zeke explained, “Two doors between you and the outside air. That’s the rule, if you can make it.”

Rector checked the polarized glass Huey’d given him. “But the air’s pretty clear, according to this.”

“Yes,” Houjin said as he reached for the second door’s handle. “But it hasn’t always been. This part collapsed about five years ago. The place we’re going … it wasn’t always underground.” He drew back the second door. Its seals complained, too, but it slid along the ground and made way for the three boys to pass.

Beyond it, Rector found himself confused.

He wasn’t inside a room, or underneath a floor or cellar. He was standing in a beautiful train car. Curtains covered the windows, and the plush seats were clean, plump, and ready to be sat upon. Small tables were installed between two of the rows, allowing people to face one another and chat or play cards.

Zeke pulled back one of the curtains, revealing a view of nothing at all—except, Rector realized, a wall of dirt. “It’s a shame, ain’t it?” the younger boy said.

“A shame, I guess. It’s real nice in here. Feels like … like…”

“It’s a Pullman car,” Houjin supplied. “One of the fanciest they ever made. The gold leaf is real, and so are the crystals. Leaded glass, all over the place. And look at the carpet!”

Rector gazed down at his feet. His boots suddenly seemed insufficient to stand upon the rug. It was Persian in design, blue with gold vines and tiny orange flowers. Instinctively, he stepped off to the side, not wanting to rub the wet dirt of the underground into the lovely pattern.

Zeke laughed, and Rector told him to shut his mouth. But he said, “Naw, I’m not laughing at you—I’m just laughing. Everybody does that, is all. This is one of the prettiest places in the city, this little car right here, and even the rough old Station men don’t want to bother it any.”

“Sometimes Yaozu comes here and smokes,” Houjin said quietly, like he was passing on a secret. “I heard he makes the chemists come in here and clean it, keep it all dusted and shiny.”

Zeke gave Rector a nudge. “Anyway, come on. We can’t work in here. Yaozu would throw a hissy fit if we smudged one of the brass fixings, or anything like that. Huey, are we headed for your workshop?”

“Yes!”

“You have a workshop?” Rector stepped back onto the carpet because he had no choice, but he tiptoed gently to keep from smushing it.