SO, MMA RAMOTSWE,” said Mr. J.L.B. Matekoni. “So you received a big letter today.”

They were sitting on the veranda at Zebra Drive at that companionable hour when the late afternoon shades almost imperceptibly into early evening. The sky was not yet dark, but had become paler, and pinker, too, in the west. Dusk was not far off, but had not yet made its softening mark; yet the birds knew, and were flying from tree to tree restlessly, finding just the right place to spend the impending night. A pair of Cape turtle doves, as married as the couple sitting on the veranda, edged closer to one another on the bough of the acacia tree that sheltered part of Mr. J.L.B. Matekoni’s vegetable garden. Their anxious cooing could be heard alongside the sound of a car making its way home to a neighbouring house, the half-hearted barking of a neighbour’s dog, the sound of a radio somewhere indeterminate.

Mr. J.L.B. Matekoni, unusually for him, was drinking a beer. He drank very little, and Mma Ramotswe hardly at all, but on the occasional evening he would unwind with a glass of Lion lager, savouring the feel of the damp, cold glass against his hand almost as much as the freshening sharpness of the beer. Mma Ramotswe would sometimes accompany him, as she did now, taking a teaspoon of beer-a single teaspoon-and putting it into a glass of water with a slice of lemon. The resulting concoction she would sip at, convinced that even this quite homeopathic dilution would go to her head if consumed too quickly.

They had raised their glasses to one another in salute, and then he had asked his question about the letter. Charlie had mentioned it that morning as they were attending to a recalcitrant gearbox, but he had not known what the letter contained. “Big news, I think, Boss,” he had said. “A letter from America means a big case.”