Mma Ramotswe warned her friend about jumping to conclusions. “It’s a very common fear for us women,” she said. “Most women worry that their husband’s eye might start to wander. And his hands too, Mma. That’s natural enough. But you shouldn’t imagine that he’s having an affair unless you have some reason to think that. Have you got any reasons?”

“Reasons? You’re asking me for reasons? I’m telling you, Mma, any woman whose husband is carrying on just knows what’s going on. You feel it. He sits there smiling and you think, What has he got to smile about? And then you suddenly find out that he has bought himself some of that aftershave stuff and is putting it on his face. You think, So why is he putting that stuff on now when he never used to put it on? Never? That is the sort of thing you think, Mma, and it all adds up. Then you say to yourself, He is having an affair-I know it.”

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.

“You can ask me,” said Mma Ramotswe, “and I shall say yes.” The words came out almost without having been thought about, but she knew that she was bound by them.

Mma Mateleke, who had been sitting with shoulders hunched in tension, now relaxed. “Please will you find this evidence that I need. Please will you find who is this woman he is having an affair with. Her name. Where she lives. What she looks like. It will not be hard for you.”

Mma Ramotswe had to acknowledge that it would not. It was difficult to conceal an affair in Gaborone, as there were not all that many places to go, and where there were a thousand eyes and ears. If Herbert Mateleke was seeing somebody else, then she would find out quite quickly. There was something, though, that was still troubling her, and she now raised this with her friend. “May I ask you, Mma, what you intend to do with the information, once you have it? I always ask clients that-it is not just you.”

This inquiry seemed to take Mma Mateleke by surprise; it was as if the answer were so obvious that the question need not have been asked. “It is so that I can divorce him,” she said abruptly. “Why else would I want to know?”

Several other reasons crossed Mma Ramotswe’s mind, but she did not reveal them. So that you might forgive him, she thought. So that you might plead with the other woman not to break up your marriage, and might succeed. So that you might reflect on why he feels it necessary to have an extramarital affair in the first place.

“Very well,” said Mma Ramotswe. “I will look into this. I don’t think that it will take long. And…” She hesitated.

“And what, Mma?”

“And it may be that Herbert is innocent,” she said. “After all, some men are, you know.”

MMA RAMOTSWE was in a thoughtful mood when she returned to the office. Mr. J.L.B. Matekoni-and Mma Potokwane too, for that matter-had occasionally said that she had a soft heart and that “no” was not one of the words that her heart understood. She had laughed at the appraisal; in her view, Mr. J.L.B. Matekoni was every bit as soft-hearted as she was-he would never turn anybody away, and would fix even the most mechanically hopeless cars-and as for Mma Potokwane, well, everybody knew that she would do anything for those orphans she looked after, and if that was not a sign of a soft heart, then what was? So although she knew that she should have declined to help Mma Mateleke, she also knew that she could not refuse her friend. But she did not relish the task that lay ahead of her, as it would involve watching somebody she knew, and that was not a good idea.

It was easy enough watching a stranger. One could sit in one’s van and pretend to be reading, or even sleeping. Plenty of people did that: they sat in their cars, talking to friends or listening to the car radio, or even just sitting. Nobody would have reason to be suspicious of that. But if one sat in one’s van outside the house of somebody one knew, and then followed him as he turned out of the drive, one would obviously be noticed. She imagined the scene, as Herbert Mateleke asked her, “Mma Ramotswe, I saw you sitting outside my house yesterday afternoon. It was you, wasn’t it? I’m sure it was. And then when I drove off down the road, you followed me. Perhaps you wanted me to show you the way, Mma…” And she would not know what to say, but would mumble something about how small the town was, in spite of being so big, and how easy it was to bump into people one knew along the road, just as easy, in fact, as in one of those tiny villages…

By the time she had reached the shared premises of the No. 1 Ladies’ Detective Agency and Tlokweng Road Speedy Motors, she had decided that she could not possibly follow Herbert Mateleke, and that the only thing to do was to stick to the procedure that she used in so many of her cases. If she wanted to find out the answer to anything, then she simply had to ask somebody. It was that simple, it really was, and she had done this on numerous occasions, with conspicuously successful results. Sometimes the answer she received was direct; on other occasions it was not so direct, but was nonetheless unambiguous. She remembered how, in one investigation into pilfering in an office-disappearing petty cash and so on-she had simply called the staff to attend a meeting. Then, as they all stood before her, some twelve people, she had said, “Now then, everybody, the manager says that money has been stolen, and I wonder who’s doing it?” And immediately all pairs of eyes had turned and looked at one member of staff, who had stared steadfastly at the ground. People know, she thought; they know things that they might be unwilling to say. Nobody in that office would have been willing to denounce the offender openly, but we reveal so much through our eyes. Our eyes, she thought, show what is in the heart.