The guard the women called LT returned at sunrise. They had hidden Sorrel under a pile of bedding, and she could just hear him say, “No one leaves the barracks today because of the dust. Give me all your algaskins, I’ll fill them up. You’ll get some soup at midday. Maybe. If I find anyone outside, they’ll die and not quickly.”

She heard the scraping sound of bolts being pulled across.

“Suppose there’s a fire, LT?” one of the women called.

“Then you’ll burn up. Settle down now. The dust might not last for long.”

Time passed. Sorrel felt sick thinking of Bibi being tortured.

“You can come out now,” Selan said eventually. “Here. Drink something. We have extra.”

Sorrel took the algaskin and tipped it to her mouth. The water had the same sharp taste as the river in Jiba. The Toplanders seemed to have the best of all things – a clean, running river. She wondered if its level was falling too.

It was getting lighter. The women sat or lay on their beds. They did not seem malnourished, but most had scars on their faces. One was missing an ear, another an eye. Some talked quietly together, others dozed. Some stared at the roof, their hands behind their heads. Petal was weaving thick grass into a round sling. “Macrame,” she explained. “Old-time craft. My grandmother showed me how to do it.”

“What are you making?”

“A sling for a calabash. The material is khus-khus grass, which has many uses. We have dozens of slings; I’m really doing it to pass the time.”

“That guard locked us in?”

“Yes. They’re afraid we’ll run in the dust.”

“Will you tell me about the camp? About what’s happening to my mother?”

Petal sighed, her fingers flying back and forth. “You really want to know about your mother?”

“Yes,” Sorrel said. She watched Petal’s hands. Her own were shaking. She sat on them.

“Drax is the colonel here. That’s what he calls himself anyway; they like to think of themselves as an army. The original settlers here were all one family, the Nelsons, just what you heard in Bana: rich people who used to be in business; government, before the Domins took over. I think some of them had family houses in the mountains from before the Convergence, so they knew what it was like up here. The Nelson family used to own the tech centres. Maybe still do.

“They needed labour, so they started to capture anyone they could. At first, they caught males, but males were too inclined to fight back so they decided on female slaves, who could also service the men and keep them happy. Colonel Drax is obsessed with military campaigns, especially genocide. He’ll read about them to you while he’s – ” She stopped.

“While he’s what?”