THEY LEFT THE WOMAN, but only after she had given them a list of other friends of the late Mma Sebina, senior. None of these women knew her as well as she did, of course, but she was sure that they would confirm what she had told them. And then, with the storm clouds now virtually upon them, they made their way back to the tiny white van.

“We can’t go and look for these people in the rain,” said Mma Ramotswe, glancing up at the purple clouds. “We shall have to come back.”

“We shall have to come back,” agreed Mr. Polopetsi, who had a habit of repeating what was said to him; an innocuous enough habit, until one noticed it.

Mma Ramotswe turned the van and they had just started back when the first drops of rain began to fall. First there was that smell, that smell of rain, so unlike anything else, but immediately recognisable and enough to make the heart of a dry person soar; for that, thought Mma Ramotswe, is what we Batswana are: dry people, people who can live with dust and dryness but whose hearts dream of rain and water. Now, in great veils, the rain fell upon Botswana; great purple-white veils joining sky to land, soaking the parched landscape.

They drove down the road through the welcome deluge, travelling slowly for the puddles and sheets of water that were forming so quickly. The tiny white van, valiant in every sort of condition, ploughed through the water like an albino hippo, while its windscreen wipers swept backwards and forwards, making it possible, just, to see a few yards ahead through the downpour. But then, as if overcome by the sheer effort of pushing aside so much water, the wipers collided with one another and became stuck. Immediately Mma Ramotswe and Mr. Polopetsi were as if shrouded in a completely impenetrable mist.

“I cannot carry on driving if I cannot see,” said Mma Ramotswe. “We shall have to stop.”

She drew the van to the side of the road, or to what she hoped was the side of the road; it was impossible to see even that.

Mr. Polopetsi rubbed at the steam on the passenger window with the sleeve of his jacket. “I will get out and fix those, Mma,” he said. “They are just stuck.”

Mma Ramotswe made a clucking sound with her tongue. “You don’t need to do that, Rra. You will get soaked. Wait until it eases a bit.”

Mr. Polopetsi peered through the small circle he had cleared in the condensation. “It will not clear quickly. This rain is going to go on for some time. I do not mind a bit of nice warm rain, Mma.” He turned to grin at her. “Why should I mind that? We have waterproof skins, do we not, Mma? Is that not what God has given us?”