They were slow to open the door to her knocking, and when it was opened it was done in such a way that it could be quickly slammed shut. She saw a figure within which at first she could not make out, and then she recognised her mother-in-law, and she caught her breath. She was aged now, and stooped, but it was the same woman whom she had not seen for many years, and who recognised her too, after a moment’s hesitation.

For a while neither woman spoke. There was so much that could be said, and Mma Ramotswe might have wept in the saying of it, but that was not what she had come for, and this woman did not deserve that. She had always sided with Note, of course, and had turned a blind eye to what was going on, but then what mother would admit to others, or to herself, that her own son was capable of such cruelty?

After a minute or so, the older woman moved slowly to one side and nodded. “You should come inside, Mma,” she said.

Mma Ramotswe stepped into the house, noticing the smell as she did so. This was the odour of poverty, of life on the edge of making do; the smell of carefully husbanded cooking fuel, of clothes that were not washed frequently enough—for lack of soap. She glanced around. They were in a room which served as a living room and kitchen. A naked bulb burned weakly above a table on which a half-empty jar of jam stood flanked by a couple of knives and a folded cloth. On a shelf at the other end of the room was stacked a small number of tin plates and several steel cooking pots. A picture, cut out of a magazine, had been pinned to the wall beside the shelves.

She had been in this house many times before. That had been a long time ago, and she was now feeling the usual effect of memory, which was to diminish places, to make them more cramped and shabbier than they had once appeared. It was as though one was looking at the world from a long way away, and it was smaller. She tried to remember exactly when it was that she had last been here, but it was too many years ago, and the painful memories had been obliterated.

“I am sorry that I have come to your house so late at night,” said Mma Ramotswe. She spoke respectfully, because this was an old woman she was addressing, and it did not matter that she was the mother of Note Mokoti—she was an old Motswana lady and that was enough.

The woman looked down at her hands. “He is not here,” she said. “Note is not here.”

Mma Ramotswe did not say anything. On the other side of the room two doors led off into the rest of the house, the bedrooms. These were both closed.