She lifted her foot off the accelerator to see if that would help, but all that it did was to reduce the volume of the knocking sound. And when she put her foot down on the pedal again, the noise resumed. Only at a very slow speed, barely above walking pace, did the sound disappear altogether. It was as if the van was saying to her: I am old now; I can still move, but I must move at the pace of a very old van.

She continued her progress down Zebra Drive, steering the van carefully through her gateway with all the care of a nurse wheeling a very sick patient down the corridor of a hospital. Then she parked the van under its habitual tree at the side of the house and climbed out of the driving seat. As she went inside, she debated with herself what to do. She was married to a mechanic, a situation in which any woman would revel, especially when her car broke down. Mechanics made good husbands, as did carpenters and plumbers-that was well known-and any woman proposed to by such a man would do well to accept. But for every advantage that attended any particular man, it always seemed as if there was a compensating disadvantage lurking somewhere. The mechanic as husband could be counted on to get a car going again, but he could just as surely be counted upon to be eager to change the car. Mechanics were very rarely satisfied with what they had, in mechanical terms, that is, and often wanted their customers-or indeed their wives-to change one car for another. If Mma Ramotswe told Mr. J.L.B. Matekoni that the tiny white van was making a strange noise, she knew exactly what he would say, as he had said it all before.

“It's time to replace the van, Mma Ramotswe,” he had said, only a few months earlier. And then he had added, “No vehicle lasts forever, you know.”

“I know that, Mr. J.L.B. Matekoni,” she said. “But surely it's wrong to replace a vehicle that still has a lot of life left in it. That's not very responsible, I think.”