Mma Ramotswe felt unhappy about the lack of proof, but that was as a detective. As a woman she knew exactly what Mma Mateleke was talking about, and she knew, too, that her fears were likely to be well founded. Men had affairs; that is what men did, and even if she had previously assumed that Herbert Mateleke was a settled, rather conservative man, she had to admit that even settled, conservative men had affairs. In fact, they were often the worst of all.

There was another thing that was worrying her. Herbert Mateleke might not be a close friend, but he was the husband of a friend, and that was worrying. Clovis Andersen had advice to give on this topic and, as usual, it was wise counsel. Do not act for friends if you can possibly avoid it, he wrote in The Principles of Private Detection. And then he continued, And the reason for this? Experience has taught me that if you act for a friend you will take the friend’s perspective on things. You will see things that the friend wants you to see because you are emotionally involved in the case. So here is Rule 32: Remember when to say no to a case. Better to lose a fee than to lose a friend.

Mma Ramotswe sipped at her tea. Mma Mateleke had yet to ask her to investigate on her behalf, but she was sure that such a request was coming. And it was.

“I know that you are very busy, Mma Ramotswe,” said Mma Mateleke, adding, “Everybody is busy these days. The whole of Botswana is busy.”

Mma Ramotswe considered this last observation. Was the whole of Botswana busy? Certainly people seemed busy enough in Gaborone, but she was not so sure about the country areas. In fact, there were many people out in the country who did not appear very busy at all. These were the people who sat outside their houses and watched the cattle amble past, or those who stood under trees and spoke with friends, or who put a chair somewhere in the sun and then sat on it. And that, surely, was how life should be. What was the point of rushing around as if everything had to be done today when there was plenty of time ahead of you, years and years, if you were lucky?

“But even if you are busy,” Mma Mateleke continued, “you might still find the time to do this favour I’m asking of you, my sister.”

My sister—the two words were very powerful, and Mma Ramotswe knew it. This was an appeal to something that went beyond the normal incidence of friendship. This was an appeal to the African sense of mutual help, and the duty to give such help. You did not call somebody your sister unless you believed in all that—as Mma Ramotswe did. And Mma Mateleke, of course, knew that Mma Ramotswe believed.