Mma Makutsi held up a hand in a placatory gesture. “Listen, Charlie, you cannot say …”

“Yes, I can,” said Charlie. “Boys have feelings too. I don’t want eight hundred pula from you. I do not even want two pula. If you offered to give it to me, I would not take it. Warthog.”

Mma Ramotswe rose to her feet. “Charlie! You are not to call Mma Makutsi a warthog. You have done that before. I will not allow it. I shall have to speak to Mr J.L.B. Matekoni.”

He moved towards the door. “I am right. She is a warthog. I do not understand why that Radiphuti wants to marry a warthog. Maybe he is a warthog too.”

BY THREE O’CLOCK in the afternoon, Mma Ramotswe had taken to looking at her watch anxiously. She wondered now whether the premise upon which she had based her letter to Aunty Emang was entirely wrong. She had no proof that Aunty Emang was the blackmailer—it was no more than surmise. The facts fitted, of course, but facts could fit many situations and still not be the full explanation. If Aunty Emang was not the blackmailer, then she would treat her letter simply as any other one which she received from her readers, and would be unlikely to put herself out by coming to the office. She looked at her watch again. The excitement of Charlie’s outburst earlier on had dissipated, and now there was nothing more to look forward to but a couple of hours of fruitless waiting.

Shortly before five, when Mma Ramotswe had reluctantly decided that she had been mistaken, Mma Makutsi, who had a better view from her desk of what was happening outside, hissed across to her, “A car, Mma Ramotswe, a car!”

Mma Ramotswe immediately tidied the magazines off her desk and carefully placed her half-finished cup of bush tea into her top drawer. “You go outside and meet her,” she said to Mma Makutsi. “But first tell Mr Polopetsi to come in.”

Mma Makutsi did as she was asked and walked out to where the car was parked under the acacia tree. It was an expensive car, she noticed, not a Mercedes-Benz, but close enough. As she approached, a remarkably small woman, tiny indeed, stepped out of the vehicle and approached her. Mma Ramotswe, craning her neck, saw this from within the office, and watched intently as Mma Makutsi bent to talk to the woman.

“She’s very small,” Mma Ramotswe whispered to Mr Polopetsi. “Look at her!”

Mr Polopetsi’s jaw had opened with surprise. “Look at her,” he echoed. “Look at her.”

Aunty Emang was ushered into the office by Mma Makutsi. Mma Ramotswe stood up to greet her, and did so politely, with the traditional Setswana courtesies. After all, she was her guest, even if she was a blackmailer.

Aunty Emang glanced about the office casually, almost scornfully.