Susan took her cue. “I decided to come back to Botswana,” she said, “because I’d been so happy here. I wanted to see the place I loved so much. I wanted to see some of the people.”

Mma Ramotswe wrote on her pad: Place. People.

“May I show you a photograph, Mma Ramotswe?”

Susan dug into the handbag she was carrying and extracted a black-and-white photograph. It was a large print, the size of a paperback book, and its edges were scuffed. As she passed it to Mma Ramotswe, Mma Makutsi rose from her chair and came to look over her shoulder.

“That is me when I was about seven,” said Susan. “And that lady was the nurse my parents engaged to help look after me. She was called Rosie. She had a Setswana name, but I’m afraid I don’t know what it was.” She looked apologetic. “I wish I could ask my parents—they might have known, but my mother died, you see, a few years back and my father…well, his memory is very weak now—he’s in a home. He can’t remember much about Botswana.”

Mma Ramotswe nodded sympathetically. “It is very sad to lose your world.”

Susan pointed to the photograph. “You see her face?”

Mma Ramotswe peered at the photograph. A young girl wearing a faded frock, barefoot, stood beside a woman somewhere in her late twenties—or so it seemed; it was difficult enough, even in the flesh, to tell ages with faces that did not line; harder yet with a photograph such as this, which was blurred. It was as if a filter had been placed across it, softening the edges, draining definition. Mma Ramotswe could tell that the woman was a Motswana—there was something familiar about the face, the bone structure, that enabled her to recognise a kinswoman.

The woman was smiling—not in the strained way in which people may smile in photographs, told to do so by the photographer, but in the natural way of one who wants to smile; who is happy; who is with somebody she loves.

“You were fond of that woman?” asked Mma Makutsi.

“Very,” said Susan. “Very, very fond. She was like a second mother to me.”

“That can happen,” said Mma Ramotswe. “That is why it is a fortunate thing to have a nursemaid. You have one mother, and then you have another mother.”

Susan reached out to touch the photograph. Mma Ramotswe noticed the gentleness—the reverence—with which she did this. And she thought of the photograph that she kept in the living room at Zebra Drive—the photograph of her late father, Obed Ramotswe, and of what it meant to her. The photographs of late people had a power beyond that of the photographs of those who were still with us…She stopped. This woman, this Rosie, was not necessarily late; and that, Mma Ramotswe realised, was why Susan was here.