Cleo leads the way onto the boardwalks, and soon I can make out the workers. They’re all clustered near the dead ends, only their torsos and heads visible. They’re not standing on the walkways, I realize as we draw nearer. They’ve only used the planks to gain easy access to the hot pools.

When we come to one of the boardwalk’s dead ends, Cleo flicks a pair of leather gloves against my chest. “Put these on,” she says.

Several workers are already here, breaking growth from the edge of the steaming pool and lowering their harvest into glass jars. The stench of rotten eggs is more pungent than ever. I loosen my scarf and pull it over my nose with a gag.

“You’ll get used to the smell,” Cleo says, and it must be true because no one else has bothered to shield their nose with their garments.

Cleo lowers herself off the boardwalk and creeps toward the pool. At the edge, she points to the pale yellow growth. “Sulfur. The third and final ingredient in black powder.”

“I expected you to be more secretive about all this,” I admit.

“Ingredients are the easy part, and everyone here knows the three materials necessary for production. The real secret is in how they are combined—the precise ratios and measurements, the order in which they are mixed. That is something only the Chemist and the Prime know.”

“Where is this Chemist? I want to meet her.” So I can ask if the black powder recipe is written down somewhere—if it’s written in the Old World language or something else entirely, and if she knows how to read it, I add mentally.

“She checks in on us occasionally, but most days she’s in the kitchen. She does all the mixing, actually makes the powder. They don’t call her the Chemist for nothing.”

So if anyone can read, it’s this woman. Maybe I can get Asher to show me where the kitchen is later.

“Now quit delaying and get over here,” Cleo says, beckoning with a finger.

I eye the pool hesitantly. “What about geysers?”

“This one never blows. Pool three erupts daily during our lie-down. Pool seven every third morning. We’ve got charts to keep track of everything. Now, let’s go. It’s safe.”

No one else along the pool’s edge looks remotely nervous, and from what the Prime said last night, her people have been harvesting like this for ages. I quit stalling and scramble down to join Cleo. She demonstrates how to break the sulfur growth free and how to stack the pieces inside a glass jar so it can be easily transported back to Powder Town.