“And they’d be chucking javelins at us the whole time we were setting the fire,” Trix muttered.

“Think,” Cade said, putting his head in his hands. For a moment he stayed like that, resting his eyes as thoughts rattled around his head. Chemistry was clearly the answer. In fact, he had solved a problem just like this one in the first round. That time he had made quicklime.

“It’s an ingredient to a substance that we need to create. I think we need to look at the ancient uses for sulfur, not the modern ones. They wouldn’t have had chemicals and reactors and whatnot. Just clay pots, water, soil, that sort of thing.”

As he spoke, a memory swam to the surface. It was there on the edge. Something he had considered, all those months ago, when contemplating the exact same problem. But he had discounted it due to the ingredients.

“Codex,” Cade asked, crossing his fingers, “what are the basic ingredients for gunpowder?”

“Sulphur, charcoal, and potassium nitrate.”

Cade narrowed his eyes. Two out of three. Damn.

“See?” Yoshi said, still lying on his back. “Potassium nitrate. Where are we gonna get that?”

Cade turned to the Codex.

“Codex, how did humans make potassium nitrate back when it was invented?”

The answer came lightning fast.

“They would mix manure, wood ash, straw, and urine. After approximately eight months, they would boil and filter the remaining liquid with charcoal and cloth, then cool the liquid to form potassium nitrate crystals.”

For a moment, they sat in stunned, disappointed silence.

“Eight months!” Bea choked. “We don’t even have that many days!”

Cade pinched the bridge of his nose. The Romans had been given a whole year. If they had been patient, they might have been able to figure this out and could have begun making gunpowder with all the time to spare.

Now it was too late.

“This is an old answer to an old game,” Yoshi said. “It’s a dead end.”

The words rang hollow in Cade’s ears. He had misread the game. Misread everything. Perhaps Abaddon truly had abandoned them to death.

Whatever member of the pantheon who ruled this part of Acies might have become sick of these Romans living here. And as a favor, Abaddon had sent Cade’s crew to convince the Romans into suicidal attack. To rid himself of Earth forever, and start anew—as he said he had done with Mars billions of years before.

Despair had become a familiar feeling since he had first arrived on Acies, and this moment was no different. But a kernel of stubbornness remained.

Abaddon had spent a long time creating the caldera. Populating it with remnants, cherry-picking people and artifacts from Earth. Most had never been used.

And while an immortal being like Abaddon would have immeasurable patience, Cade imagined that a so-called god would be loath to leave so much wasted potential behind.

“No,” Cade growled. “There’s something to this, I know it.”

“Cade…,” Amber said, touching him gently on the arm. “No one blames you. We’ll find another way.”