“So this is the No. 1 Ladies’ Detective Agency,” she said. “I have heard of this place. I did not think it would be so small.”

Mma Ramotswe said nothing, but indicated the client’s chair. “Please sit down,” she said. “I think you are Aunty Emang. Is that correct?”

“Yes,” said the woman. “I am Aunty Emang. That is me. And you are this lady, Precious Ramotswe?” Her voice was high-pitched and nasal, like the voice of a child. It was not a voice that was comforting to listen to, and the fact that it emanated from such a tiny person made it all the more disconcerting.

“I am, Mma,” said Mma Ramotswe. “And this is Mma Makutsi and Mr Polopetsi. They both work here.”

Aunty Emang looked briefly in the direction of Mma Makutsi and Mr Polopetsi, who was standing beside her. She nodded abruptly. Mma Ramotswe watched her, fascinated by the fact that she was so small. She was like a doll, she thought; a small, malignant doll.

“Now this letter you wrote to me,” said Aunty Emang. “I came to see you because I do not like the thought of anybody being worried. It is my job to help people in their difficulties.”

Mma Ramotswe looked at her. Her visitor’s small face, with its darting, slightly hooded eyes, was impassive, but there was something in the eyes which disturbed her. Evil, she thought. That is what I see. Evil. She had seen it only once or twice in her life, and on each occasion she had known it. Most human failings were no more than that—failings—but evil went beyond that.

“This person who says that she knows somebody who is a blackmailer is just talking nonsense,” went on Aunty Emang. “I do not think that you should take the allegation seriously. People are always inventing stories, you know. I see it every day.”

“Are they?” said Mma Ramotswe. “Well, I hear lots of stories in my work too, and some of them are true.”

Aunty Emang sat quite still. She had not expected quite so confident a response. This woman, this fat woman, would have to be handled differently.

“Of course,” Aunty Emang said. “Of course you’re right. Some stories are true. But why would you think this one is?”

“Because I trust the person who told me,” said Mma Ramotswe. “I think that this person is telling the truth. She is not a person to make anything up.”

“If you thought that,” said Aunty Emang, “then why did you write to me for my advice?”

Mma Ramotswe reached for a pencil in front of her and twisted it gently through her fingers. Mma Makutsi saw this and recognised the mannerism. It was what Mma Ramotswe always did before she was about to make a revelation. She nudged Mr Polopetsi discreetly.

“I wrote to you,” said Mma Ramotswe, “because you are the blackmailer. That is why.”