Mr. Polopetsi’s eyes were fixed on the floor. “But it works, Mma Potokwane. I put in some money and within a few months I had it back, plus twenty-five per cent.”

Mma Ramotswe was gentle. “Yes, Mr. Polopetsi, I’m sure you did get all that. And I would never accuse you of dishonesty. But you have to ask yourself: Where did your profit come from?”

“From the sale of the fat cattle.”

Mma Potokwane shook her head. “I don’t think so, Rra. I think it probably came from the investment of the next person who joined.”

Mr. Polopetsi looked at her blankly. “But that money would be used to buy more cattle.”

“Some of it might be,” said Mma Potokwane. “But the rest of it would be used to repay earlier investors. So at the end of the day, the people at the beginning make money, while those at the end find their money has disappeared and there are no cattle for them—nor any profits.” She waited for what seemed like an unduly long time, and then said, “There’s a special name for this sort of thing. It’s called a pyramid scheme.”

Mr. Polopetsi sat quite still. When he spoke, his voice was faltering. “He said that everything was all right. He said there were many people doing these things.”

“Who said this?” asked Mma Potokwane.

Mr. Polopetsi gestured towards the table at which he had been sitting. “My business associate.”

“That great financial magician,” said Mma Potokwane.

Mr. Polopetsi, defeated and crumpled though he was, suddenly seemed to acquire the strength to defend himself. “He is a good man,” said Mr. Polopetsi. “He said that he would be helping the farmers from the drought areas. That is a good thing to do, don’t you think?”

Mma Ramotswe sighed. “Oh, Mr. Polopetsi! You are a good man, Rra—I’ve always known that. But you are not the sort to get mixed up in this sort of thing. You may want to help the farmers suffering from the drought, but I really don’t think your friend has that in mind. I think he’s using you, Rra.”

Mma Potokwane nodded her agreement. “Yes, Rra—you are being used.”

“So now,” went on Mma Ramotswe, “you need to tell us how many people you have persuaded to invest in the Fat Cattle Club.”

“Not very many,” muttered Mr. Polopetsi.

“How many?” pressed Mma Ramotswe.

Mr. Polopetsi swallowed hard. “Four,” he said.

“Including Mma Makutsi?” asked Mma Ramotswe.

“Five,” said Mr. Polopetsi.

Mma Ramotswe drew in her breath. “We shall have to make a plan,” she said. “Don’t approach anybody else. Do you understand? Not one more person—not one.”

He lowered his head. “I am a very foolish man,” he said.

“I think so too,” said Mma Potokwane.