Now what should she do? She could stay where she was in the hope that somebody came out of the back door, but why should they bother to do that? And if they did, then what would she do?

Suddenly a window at the back of the house opened and a man leaned out. It was Dr Komoti.

"You! You over there! Yes, you, fat lady! What are you doing sitting under our mulberry tree?"

Mma Ramotswe experienced a sudden, absurd urge to look over her shoulder, as if to imply that there was somebody else under the tree. She felt like a schoolgirl caught stealing fruit, or doing some other forbidden act. There was nothing one could say; one just had to own up.

She stood up and stepped out from the shade.

"It is hot," she called out. "Can you give me a drink of water?"

The window closed and a moment or two later the kitchen door opened. Dr Komoti stood on the step wearing, she noticed, quite different clothes from those he had on when he left Gaborone. He had a mug of water in his hand, which he gave to her. Mma Ramotswe reached out and drank the water gratefully. She was, in fact, thirsty, and the water was welcome, although she noticed that the mug was dirty.

"What are you doing in our garden?" said Dr Komoti, not unkindly. "Are you a thief?"

Mma Ramotswe looked pained. "I am not," she said.

Dr Komoti looked at her coolly. "Well, then, if you are not a thief, then what do you want? Are you looking for work? If so, we already have a woman who comes to cook in this house. We do not need anybody."

Mma Ramotswe was about to utter her reply when somebody appeared behind Dr Komoti and looked out over his shoulder. It was Dr Komoti.

"What's going on?" said the second Dr Komoti. "What does this woman want?"

"I saw her in the garden," said the first Dr Komoti. "She tells me she isn't a thief."

"And I certainly am not," she said indignantly. "I was looking at this house."

The two men looked puzzled.

"Why?" one of them asked. "Why would you want to look at this house? There's nothing special about it, and it's not for sale anyway."

Mma Ramotswe tossed her head back and laughed. "Oh,

I'm not here to buy it," she said. "It's just that I used to live here when I was a little girl. There were Boers living in it then, a Mr van der Heever and his wife. My mother was their cook, you see, and we lived in the servants' quarters back there at the end of the garden. My father kept the garden tidy…"

She broke off, and looked at the two men in reproach.

"It was better in those days," she said. "The garden was well looked after."

"Oh, I'm sure it was," said one of the two. "We'd like to get it under control one day. It's just that we're busy men. We're both doctors, you see, and we have to spend all our time in the hospital."

"Ah!" said Mma Ramotswe, trying to sound reverential. "You are doctors here at the hospital?"

"No," said the first Dr Komoti. "I have a surgery down near the railway station. My brother…"

"I work up that way," said the other Dr Komoti, pointing vaguely to the north. "Anyway, you can look at the garden as much as you like, mother. You just go ahead. We can make you a mug of tea."

"Ow!" said Mma Ramotswe. "You are very kind. Thank you."

IT WAS a relief to get away from that garden, with its sinister undergrowth and its air of neglect. For a few minutes, Mma Ramotswe pretended to inspect the trees and the shrubs-or what could be seen of them-and then, thanking her hosts for the tea, she walked off down the road. Her mind busily turned over the curious information she had obtained. There were two Dr Komotis, which was nothing terribly unusual in itself; yet somehow she felt that this was the essence of the whole matter. There was no reason, of course, why there should not be twins who both went to medical school-twins often led mirrored lives, and sometimes even went so far as to marry the sister of the other's wife. But there was something particularly significant here, and Mma Ramotswe was sure that it was staring her in the face, if only she could begin to see it.

She got into the tiny white van and drove back down the road towards the centre of town. One Dr Komoti had said that he had a surgery in town, near the railway station, and she decided to take a look at this-not that a brass plate, if he had one, would reveal a great deal.

She knew the railway station slightly. It was a place that she enjoyed visiting, as it reminded her of the old Africa, the days of uncomfortable companionship on crowded trains, of slow journeys across great plains, of the sugarcane you used to eat to while away the time, and of the pith of the cane you used to spit out of the wide windows. Here you could still see it-or a part of it-here, where the trains that came up from the Cape pulled slowly past the platform on their journey up through Botswana to Bulawayo; here, where the Indian stores beside the railway buildings still sold cheap blankets and men's hats with a garish feather tucked into the band.

Mma Ramotswe did not want Africa to change. She did not want her people to become like everybody else, soulless, selfish, forgetful of what it means to be an African, or, worse still, ashamed of Africa. She would not be anything but an African, never, even if somebody came up to her and said "Here is a pill, the very latest thing. Take it and it will make you into an American." She would say no. Never. No thank you.

She stopped the white van outside the railway station and got out. There were a lot of people about; women selling roasted maize cobs and sweet drinks; men talking loudly to their friends; a family, travelling, with cardboard suitcases and possessions bundled up in a blanket. A child pushing a homemade toy car of twisted wire bumped into Mma Ramotswe and scurried off without an apology, frightened of rebuke.

She approached one of the woman traders and spoke to her in Setswana.

"Are you well today, Mma?" she said politely.

"I am well, and you are well too, Mma?"

"I am well, and I have slept very well."

"Good."

The greeting over, she said: "People tell me that there is a doctor here who is very good. They call him Dr Komoti. Do you know where his place is?"

The woman nodded. "There are many people who go to that doctor. His place is over there, do you see, where that white man has just parked his truck. That's where he is."

Mma Ramotswe thanked her informant and bought a cob of roasted maize. Then, tackling the cob as she walked, she walked across the dusty square to the rather dilapidated tin-roofed building where Dr Komoti's surgery was to be found.

Rather to her surprise, the door was not locked, and when she pushed it open she found a woman standing directly in front of her.

"I am sorry, the doctor isn't here, Mma," said the woman, slightly testily. "I am the nurse. You can see the doctor on Monday afternoon."

"Ah!" said Mma Ramotswe. "It is a sad thing to have to tidy up on a Friday evening, when everybody else is thinking of going out."

The nurse shrugged her shoulders. "My boyfriend is taking me out later on. But I like to get everything ready for Monday before the weekend starts. It is better that way."

"Far better," Mma Ramotswe answered, thinking quickly. "I didn't actually want to see the doctor, or not as a patient. I used to work for him, you see, when he was up in Nairobi. I was a nurse on his ward. I wanted just to say hallo."

The nurse's manner became markedly more friendly.

"I'll make you some tea, Mma," she offered. "It is still quite hot outside."

Mma Ramotswe sat down and waited for the nurse to return with the pot of tea.

"Do you know the other Dr Komoti?" she said. "The brother?"

"Oh yes," said the nurse. "We see a lot of him. He comes in here to help, you see. Two or three times a week."