“Setting up a room for myself,” Rector said. “And while I was at it, I ran into Miss Angeline, carrying that cage we put out. She caught the fox. We gave it some food and water, and left it in that empty room with the door shut.”

Houjin shook his head and reached for the stair rail. Up he climbed, and he said, “Waste of time. But it’s nice of her to try—and Zeke’ll be glad she caught it. It can be his project, when he gets finished up at Decatur.”

“Why aren’t you up there? Why’d you leave with Yaozu? Is that air captain boss of yours scared of him, or what?”

“Cly’s not scared of him,” Houjin snapped. “The captain’s trying to do what’s best for the underground. Zeke can carry things and move things up at the fort as easy as I can; but he can’t make things like I can.”

“What are you making?” Rector asked, partly because he was curious, and partly because he didn’t feel like managing Houjin and his bad mood.

His small question worked. A smile spread out over Huey’s face. “Yaozu had a great idea, but he didn’t know how to make it happen. So I figured it out—it was easy as pie.”

“Well, what is this great idea?” They reached the first floor, and Houjin was nearly at a run, so it must be something good.

“We’re going to take their dynamite, and use it against them.”

Houjin stopped and faced him, and held out his hands like he could make his point better if he could gesture. “How much do you know about dynamite?” he asked.

“It blows things up.”

“Right. It blows things up, but you don’t want it to blow things up while you’re standing there holding it. You want to be a long way away when it goes off,” he said patiently. He’d lapsed into teacher mode.

Rector didn’t care for being talked down to by somebody younger than him, but he was the one who’d asked, and now he had to take the explanation however he could get it. With a minimum amount of disdain, he said, “Obviously.”

“Obviously, yes. You obviously knew that.”

“Just tell me, would you?”

“Fine. In order to control it, you have a couple of choices: You can either give it a very long fuse, and light it, or you can take a very long wire, and use that wire to send the dynamite an electric spark. It’s usually generated by one of those pump boxes: You shove the plunger down, it makes a spark, the spark goes down the line, and boom! But we don’t want to use wire, and we don’t want to use a fuse.”

Rector tried to look like he was following, but he was lost. “Then what would you use?”