Mma Potokwani’s pace became even slower. ‘Do you remember what happened to you, Rra?’ she asked. Normally Mma Potokwani spoke in stentorian tones – the result of having to make herself heard over the voices of hordes of children; now her voice was softer, gentler.

Mr J. L. B. Matekoni was not sure what she was referring to. ‘Many things have happened to me,’ he said. ‘In fact, Mma, things happen to me every day.’

‘No, no, Mr J. L. B. Matekoni. I am not thinking of ordinary things. I am thinking of when you were ill. Some years ago – remember?’

He stopped in his tracks. ‘Oh…’

Mma Potokwani was looking at him intently. ‘People get depressed, Rra – it is very common. One of the housemothers here had that happen to her just a few months ago. She sat and sat and thought about problems. One of the children came to me and said that the mother cried too much and sometimes could not manage to heat up their dinner. I knew what the trouble was.’

‘And this lady – how is she now?’

‘Good as new,’ said Mma Potokwani. ‘I took her to the doctor and they knew what was wrong. It was the same thing that happened to you.’

‘That was thanks to Dr Moffat,’ said Mr J. L. B. Matekoni.

‘Yes,’ said Mma Potokwani. ‘He is very kind.’

‘But I do not think she’s depressed,’ said Mr J. L. B. Matekoni. ‘She is eating as much as ever. She is keeping the house very well. She has no trouble with her sleeping. Dr Moffat told me that if you’re depressed you usually do none of those things.’

‘Are you sure?’ asked Mma Potokwani.

‘I am very sure, Mma. She is still laughing. When I was depressed I did not do any laughing.’

They resumed their walk. They were now near the patch of grass and dust where a group of children were playing football. They were all wearing the khaki shorts and shirts of the classroom, but were barefoot. Two teams of six, running and wriggling with all the energy that young boys can muster, battled over a somewhat deflated old leather ball, urging each other on exuberantly and raising a cloud of dust that darted about the pitch like a tiny, localised tornado.

Mr J. L. B. Matekoni called out encouragement, and Mma Potokwani gave a good-natured wave of her hand.

‘Boys,’ said Mr J. L. B. Matekoni. ‘Their batteries never seem to run down, do they, Mma?’

‘No,’ said the matron. ‘They’re on the go all day. Non-stop. I think that…’ She broke off and turned to look at Mr J. L. B. Matekoni. ‘Batteries, Rra.’

He made a gesture towards the boys. ‘Yes, look at them…’

‘No,’ she said, shaking her head. ‘Not the boys’. Mma Ramotswe’s batteries.’

He took a little while to reply. Then he said, ‘Her batteries are run down? Is that what you’re saying, Mma?’