AS IT HAPPENED, at the precise moment that Mr Polopetsi was creeping through the darkness, imagining the gratitude of his employer, Mma Ramotswe was sitting with Mr J.L.B. Matekoni at their dining table, having just completed a short conversation on the subject of Mr Polopetsi and his good work in the garage. The two foster children, Motholeli and Puso, were sitting at their places, eyes fixed on the pot of stew which she was about to serve. At a signal from Mr J.L.B. Matekoni, the children folded their hands together and closed their eyes.

“We are grateful for this food which has been cooked for us,” he said. “Amen.”

The grace completed, the children opened their eyes again and watched as Mma Ramotswe ladled their helpings onto their plates.

“I have not seen this uncle,” said Motholeli. “Who is he?”

“He is working at the garage,” said Mma Ramotswe. “He is a very good mechanic, just like you, Motholeli.”

“He is not a mechanic,” Mr J.L.B. Matekoni corrected her. “A mechanic is somebody who has had the proper training. You are not a mechanic until you have completed an apprenticeship.” The mention of apprenticeships seemed to make him sombre, and he stared grimly at his plate for a few moments. He had reminded himself of his two apprentices, and as a general rule he did not like to think too much about them. He was not sure when they would finish their apprenticeships, as both of them had failed to complete one of the courses they had been sent off on, and would have to repeat it. They had said that they had failed only because of a mix-up in the papers and an ambiguity in one of the questions about diesel systems. He had looked at them with pity; did they really expect him to swallow such a story? No, it was best not to think too much about those two when he was away from the garage.

“What I mean is that he is good with cars,” said Mma Ramotswe. “And he is a good detective too.”

“But is he really a detective?” Mr J.L.B. Matekoni asked, loading his fork with a piece of meat. “You cannot call just anybody a detective. There must be some training …” He tailed off. Mma Ramotswe had had no training, of course, although she had at least read The Principles of Private Detection by Clovis Andersen. He doubted whether Mr Polopetsi had read even that.

“Being a private detective is different from being a mechanic,” said Mma Ramotswe. “You can be a detective without formal qualifications. There is no detective school, as far as I know. I do not think that Mr Sherlock Holmes went to a detective school.”

“Who is this Rra Holmes?” asked Motholeli.

“He was a very famous detective,” said Mma Ramotswe. “He smoked a pipe and was very clever.”