Then Crier cocked her head, like she always did when she was listening intently, and a moment later Ayla heard it too: a hammering sound, like metal striking stone. It seemed to be coming from below.

“Is there a cellar?” Ayla asked Dinara in a low voice. “Is someone down there?”

Dinara took a big swill of brandy. “You done eating?” she said. Ayla nodded. “Then I’ll show you.”

She led Ayla and Crier to a corner of the room and knelt down, and Ayla saw a small metal handle attached to one of the floorboards. Dinara tugged on it and a section of the floor lifted up, revealing an entrance to the dark cellar below. There were no stairs—just a frayed-looking rope ladder. Ayla tried not to squirm. She didn’t want to climb down into the dark. She really didn’t want to go underground. But the noises were coming louder now, and her curiosity outweighed her fear.

“C’mon,” said Dinara, already lowering herself into the opening. Crier followed after, and Ayla climbed down last, gripping the sides of the ladder so tight she came away with indentations on her palms, the faint shape of braided rope.

Once she reached the bottom and her eyes adjusted to the gloom, Ayla saw it wasn’t actually pitch-black down here. A couple lanterns sat on wooden shelves along the walls, casting a dim light. And there, in the center of the room, the source of the hammering noises. Three of Dinara’s rebels sat on the floor hunched over . . . something.

“This is where they would’ve stored heartstone,” Dinara said. “Crates and crates of heartstone dust, waiting to be shipped out.”

“What are they doing?” Crier asked from behind Ayla. Her eyes were fixed on the three rebels, who hadn’t yet looked up from their work. One was hammering away, the other was taking each shard and carving something into the surface.

Without waiting for Dinara’s answer, Ayla crept closer, to the edge of the lanternlight. Now she could see the stone wasn’t black. It was a deep, deep blue.

“The blue smoke,” she said, turning back to Dinara. “This is where it comes from, isn’t it?”

Dinara hummed. “Got it in one, girl.”

Bombs. They were making bombs.

Maybe Ayla should have been scared, but all she felt was fascinated. She wanted a closer look. What was this mysterious blue stone? She’d heard of saltpeter bombs, but never anything like this. Where did it come from?

She only voiced the last question aloud.

“The caves of Tarreen,” said Dinara. “You ever wonder why everyone thinks Tarreen’s nothing but impenetrable jungle? That hardly anybody lives there, there’s only a few scattered human settlements, the whole area’s strategically useless?” She grinned, dimples flashing. “Tarreen’s not quite as abandoned—and not nearly as useless—as the sovereign thinks. The Tarreenians hide themselves well, but they exist. And they’re sitting on miles and miles of cave systems full to the damn brim of a gemstone a thousand times more powerful, more potent, than heartstone. If you know the right magick.”