They were in some kind of ravine. Sheer rock walls stretched above them. The air seemed wet and the sound of rushing water was deafening. For the first time in her life, Sorrel longed for daylight, so she could have a clear view of where she was.

Dawn came as they walked on, but it was far overhead. They were so deep in the ravine that it would probably be in shadow all day. There were real trees, with trunks and canopies and flowers, deepening the shadow thrown by the cliff walls. And there was a river at the very bottom of the ravine, blue and green and frothing white.

“Come along,” Emrallie said. “Stop gawping. We still have to find shelter – might be no direct sun, but it’s still going to heat up.”

“I didn’t know there were any rivers left,” Sorrel said.

“Not surface ones, anyway. This was underground until the earthquake, like I said. We’re not sure how long it will last – it’s already got less water than before.”

They followed Emrallie along a narrow, treacherous trail, slick with green plant growth. The air was full of spray from the river.

“Can we fill our algaskins?” Sorrel asked.

“Not here. Just follow me.”

They had to slide down the last part of the trail. They were close to the river now and the noise made conversation impossible. Emrallie threaded her way through the trees which grew closer and closer together. The light was a green gloom and insects made scratching sounds around them. She heard the whine of mosquitoes and the faint chirp of a bird. Life rustled in the undergrowth and in the leaves – what remained, she thought, of a living world. Perhaps there were fish in the river, maybe even shrimp. If there were flowers, there would be fruit. The ground was stony, but there was soil; crumbly, black soil. She reached for her mother’s hand and for the first time since they left Bana, Bibi smiled.

They could no longer see Emrallie – she was too far ahead.

“Guata, people, stop gazing!” Emrallie said, returning. “Come on!”

They emerged in a round clearing with a circle of small stones in the middle. The canopy above was unbroken. There was no one there and Sorrel wondered if this was just a resting place. As her eyes adjusted to the gloom, she saw shelters among the trees made of different materials – woven roofs, mud and stone walls, threadbare tarpaulins. Bamboo – split and laced into flat surfaces. Sheets of wood were made into lean-tos.

Now, the noise of the river was muffled, and the insect sounds came from a distance. “You’ll have to share my hut,” Emrallie said. “I hope you don’t snore.” She was looking at Bibi.

“You still sleep in the day?” Sorrel asked.

“Mostly. Sometimes we don’t. But if we want to move around outside the ravine, we have to travel at night. Needs practice.”