They saw no sign of a track leading down the hill. Perhaps no one else had thought of the old aqueduct as a trail to anywhere. Sorrel squatted. The soil was sandy and loose and she could see rocks and a few very small cacti close by, too small to reap, even if they had the space to carry them.

“It’s an abyss,” Sorrel said.

“We go down sideways,” Bibi replied. Her boots slipped but she caught her balance.

“Maybe we should go back,” Sorrel said “There’s time. We’ll find a place tomorrow night.”

“No,” Bibi said. “We’ve decided. We’ve made a plan. You hold the PlAK; your balance is probably better than mine.”

They slipped and slid down the slope led by the PlAK’s small light, directed at their feet to avoid turning an ankle. They could not look ahead. They did not know where the hill ended or if they were going in the right direction. Sorrel felt her thighs stiffening from the movement of walking downhill and she wondered how her mother was doing. Bibi was ahead testing each foothold before transferring her weight. It was good not to be alone in the darkness. They heard their own scraping, tentative steps, and the fall of loose stones. At least there were no more mosquitoes on the Lowlands, but maybe they had survived in the mountains and if they had, there would be fevers.

Her breath was now coming hard. Sorrel looked up at the sky, searching for any signs of the coming dawn. Bibi stopped. The night was impenetrable – not the velvet black of old-time night skies, salted with stars – she had only seen pictures of those – but the dark grey of dust from those far-off places that had lost all their water. What would happen to them if there was a dust storm?

“Come on,” Bibi said, as if she had not been the one to stop. The incline had become less steep. Sorrel turned on the PlAK searchlight to sweep the landscape and her mother did not object. Rocks everywhere. What chance was there they would stumble upon the aqueduct in the darkness? Maybe this was the last night of her life. Would dying of heatstroke hurt? Would it burn like the searing rock on her cheek? Might have been better to be caught in the frozen parts of the world. Freezing seemed less painful than burning. Stupid thoughts. Here was where they were.

All they could see of the land was shape and shadow, the hard, smooth silhouettes of rocks, the spiky, irregular outline of stunted plants.

“Turn off the searchlight,” Bibi said.

The land was flatter now. They began walking faster. A giant rock loomed to their left. “Let’s rest for a bit over there,” Bibi said, pointing. “Have a little drink.”

“Do we have time?”

“We can’t just blunder around until it’s day.”