Mr J.L.B. Matekoni looked sideways at Mma Ramotswe. There was something on her mind. In a marriage, he thought, it would be important not to keep anything from one’s spouse, and they might as well start that policy now. Mind you, he recalled that he had just kept the knowledge of two foster children from Mma Ramotswe, which was hardly a minor matter, but that was over now and a new policy could begin.

“Mma Ramotswe,” he ventured. “You are uneasy tonight. Is it something I have said?”

She put down her teacup, glancing at her watch as she did so.

“It’s nothing to do with you,” she said. “I have to go and speak to somebody tonight. It’s about Mma Curtin’s son. I am worried about this person I have to see.”

She told him of her fears. She explained that although she knew that it was highly unlikely that an economist at the University of Botswana would turn to violence, nonetheless she felt convinced of the evil in his character, and this made her profoundly uneasy.

“There is a word for this sort of person,” she explained. “I read about them. He is called a psychopath. He is a man with no morality.”

He listened quietly, his brow furrowed with concern. Then, when she had finished speaking, he said: “You cannot go. I cannot have my future wife walking into danger like that.”

She looked at him. “It makes me very pleased to know that you are worried about me,” she said. “But I have my calling, which is that of a private detective. If I was going to be frightened, I should have done something else.”

Mr J.L.B. Matekoni looked unhappy. “You do not know this man. You cannot go to his house, just like that. If you insist, then I shall come too. I shall wait outside. He need not know I am there.”

Mma Ramotswe pondered. She did not want Mr J.L.B. Matekoni to fret, and if his presence outside would relieve his anxiety, then there was no reason why he should not come. “Very well,” she said. “You wait outside. We’ll take my van. You can sit there while I am talking to him.”

“And if there is any emergency,” he said, “you can shout. I shall be listening.”

They both finished the meal in a more relaxed frame of mind. Motholeli was reading to her brother in his bedroom, the children having had their evening meal earlier. Dinner over, while Mr J.L.B. Matekoni took the plates through to the kitchen, Mma Ramotswe went down the corridor to find the girl half-asleep herself, the book resting on her knee. Puso was still awake, but drowsy, one arm across his chest, the other hanging down over the edge of the bed. She moved his arm back onto the bed and he smiled at her sleepily.