They drove slowly down the track. After a while, Mr J.L.B. Matekoni turned to Mma Ramotswe. “You said that it happened very close to the turn-off,” he said. “But it must have been further than you thought.”

Mma Ramotswe cast an anxious glance over her shoulder. She was sure that it was about there, at that bend, where the track went off in a different direction. Yes, it must have been that spot, but there was no sign of the van.

She looked at Mr J.L.B. Matekoni. “We must stop here,” she said. “I am very sure that it was here.”

Mr Polopetsi, who was sitting between Mr J.L.B. Matekoni and Mma Ramotswe, now leaned forward in his seat. “It has been stolen!” he exclaimed. “Your van has been stolen!”

“We’ll see,” said Mma Ramotswe. She feared that he was right, even though she felt cross with him for saying it. If her van had been stolen, then it was for her to make the announcement, not Mr Polopetsi.

They alighted from the truck and Mma Ramotswe walked over the edge of the track, a few yards behind the place where they had stopped. Looking down at the ground, she saw what she had been looking for, a patch of oil in the sand. The patch measured only six inches or so across, but it was dark and obvious, and there was now no doubt in her mind. She was looking at the place where she had had her last sight of the tiny white van, and it was undoubtedly no longer there.

Mr J.L.B. Matekoni joined her and followed her gaze, down towards the sand. “Ah!” he said, and then, turning to face her, “Ah!” again.

“It has been taken,” she said, her voice cracking. “My van. It is gone now.”

Mr Polopetsi now came to stand beside them. “Somebody must have fixed it and driven it away.”

“Very strange,” said Mr J.L.B. Matekoni. “But that means that your engine can’t have seized. It must have been something else. They would not have been able to drive it away if it had seized.”

Mma Ramotswe shook her head. “We will have to go to the police and report it. That is all we can do. They will have driven it far away by now.”

“I’m afraid that you’re right,” said Mr J.L.B. Matekoni gently. “When a vehicle is stolen, it disappears very quickly. Just like that. It’s gone.”

Mma Ramotswe turned away and began to walk back to the truck, followed by Mr J.L.B. Matekoni. Mr Polopetsi, though, stood where he was.

“We must get back,” called Mr J.L.B. Matekoni over his shoulder.