She went into their bedroom and kicked off her shoes. Then, lying down on the king-size bed that Phuti had specially ordered through his wholesaler, she closed her eyes and prepared to give in to her drowsiness. But sleep eluded her and she found herself listening to those small sounds, wondering which one of them might be a cobra. It was a hot day, and any cobra who knew anything about houses would realise that there would be plenty of cool places that offered sanctuary from the heat outside – places of darkness where a snake could lie and digest his meal and think about his next move. Places in bathrooms, places in cupboards, places under beds…

She opened her eyes. There was a movement on the ceiling above her – a movement that was almost undetectable because the creature that made it was so small. She saw what it was: a tiny gecko, attached to the ceiling by the curious sticky pads on its toes, had been stalking a fly and had pounced. She smiled. There was no reason to be frightened of creatures like that, which helped so much by keeping mosquitoes down.

Then she heard another sound. At first she wondered whether somebody had come into the house and was talking at the end of the corridor, but then, hearing it again, and louder now, she realised that it was in the room.

I’d be careful if I were you, boss.

She lay quite still. She had been wearing relatively new shoes and this pair had never addressed her before. But the voice was the same – and spoke with much the same accent as her other, older shoes.

‘What was that?’ she half-whispered.

I’d be careful, boss – that’s all.

She sat up and rubbed her eyes. This was ridiculous. Shoes could not talk – as Mma Ramotswe would say, that is well known – and yet there was no doubt in her mind that she had heard something. She considered what they had said. I’d be careful, boss. What could it mean? In the past her shoes had restricted themselves to complaints or to Delphic utterances of no great importance – the sort of thing heard from subservient, disgruntled employees. This was the first time they had uttered a distinct warning.

She told herself that it was all in her mind. People imagined that they heard things, but it was just one bit of the brain convincing another bit of the brain that something had been said.

Don’t say we didn’t warn you, boss – that’s all. But remember this: we can see things down here that you can’t see up there.