Later, they ferried the supplies from the caravan to the Webster house. It seemed to Saleh this was a standing arrangement. They left replacement parts and canned food that the Webster liked, some odd books still made out of paper, some clothes and things from faraway Yiwu, combs and glasses, soap.

In return they took the downed drone, the Roman coins, the pot from Byzantine time that was complete all but for the handle. The Sidorov embryomech egg came last. It was a long and indeed egg-shaped object of some considerable weight, dun-coloured and unremarkable. It felt warm to the touch. They loaded it onto one of the great khans that was used for transporting cargo.

The jackals watched as they departed. Saleh looked back as they began to cry up to the moon. Perhaps the jackals, too, wanted to go where he did. He didn’t know what jackals wished, what jackals dreamed. Perhaps they told this to each other as they sat at night by the campfire.

As Saleh watched, the Webster stepped out of his house and stood on his odd little porch and watched the departing caravaners. He was so entirely alone and yet he didn’t seem lonely. He had his strange home, and the jackals, and that patch of watered grass. It was like a dream and, perhaps for Websters, it was the only dream they ever had.

Then the Green Caravanserai ambled beyond the scope of that little valley, and the house and its occupant vanished from Saleh’s view and there was only the desert again.

4. The Ship

Days away from the Webster house the caravan came to a place in the desert where the sand was fused into a curious green glass, and tiny slithering robots the colour of dunes filled the landscape like tadpoles in a pool after the rain. Saleh picked one of the creatures up and dangled it by pinching one corner. It was a tapeworm sort of robot, as flat as a sheet, and wriggled desperately in Saleh’s grasp until he let it go.

“What is this place?” he said.

“It’s where the ship fell,” Elias said, smiling. “I love coming here.”

“What ship?” Saleh said.

“The ship that crashed during the last war. It was called the Compassionate Heaven, a cargo ship out from Mars on an Earth run. It was in low-earth orbit when it hit a junk cluster of old satellites. They say you could see it trailing in the sky like a comet before it hit, and the plume of the explosion for days after.”

“But that’s awful,” Saleh said. “Was anyone hurt?”