THAT EVENING, in the house on Zebra Drive, Mma Ramotswe and Mr. J.L.B. Matekoni sat out on the verandah after dinner, reviewing the events of the day. The two foster children, Motholeli and Puso, were safely in bed. Motholeli, being older, was allowed to turn her own light out after she had finished reading, provided that it was off by half past nine; Puso’s light had to be out an hour earlier than that, not that this was ever an issue with him. Like most boys, he spent his days in the relentless expenditure of energy, with the result that even by seven o’clock, when Mma Ramotswe placed the family meal on the table, he was tired to the point of exhaustion. Often Mma Ramotswe would go into his room a few minutes after the evening meal, drawing in her breath to deliver a homily on the need to tidy up the mess, only to discover the small boy lying, fully clad, on top of his blankets, already asleep.

She would gaze at him, at the perfection of his features—for he was an attractive child, with the honey-coloured skin of the Bushman side of his family, his mother and her people, but the taller build of his Motswana father. It was a good combination, a happy mixture. His Kalahari ancestors had bequeathed him eyes that shone with light, and the quick, darting manner of those who lived by their wits in a harsh land. He could spot things from a great distance—she had noticed him doing it when they were out in the bush. He could see a bird on a branch of an acacia tree when others could barely see the tree, and he could make out the light brown smudge of a nervous impala where others would think there was just grass and thorn bushes and sand.

“You could be a great tracker,” Mr. J.L.B. Matekoni said to him once. “You have that gift from your people.”

But Puso had turned away and said nothing. He is ashamed, thought Mr. J.L.B. Matekoni; he is ashamed of what he is. He had tried to talk to him about it, but Puso had simply run away, out into the garden.

“What do we do, Mma Ramotswe?” asked Mr. J.L.B. Matekoni. “What do we say to him? Can you…”

“I’ll try,” she said.

And she did, having waited for her moment, which came when she was sitting with Puso in her tiny white van. She was driving to Mochudi and he had come to keep her company, and she brought up the subject of his past.

“We took you and Motholeli in because we loved you,” she said. “You know that, don’t you?”

He looked down at his hands, folded on his lap in front of him. His voice was small when he replied. “Yes. I know that.”