The supermarket was not busy, although there were short lines of people at the bakery and meat sections. They avoided these, and walked instead down the curry and pasta lanes. Mma Makutsi reached for a jar of peri-peri sauce and put it into the tray.

“Phuti likes peri-peri chicken,” she explained. “He has a taste for hot things.”

“I can’t stand it,” said Charlie. “Why spoil good food by making it so hot that it burns your mouth? What’s so good about having a burnt mouth, Mma Makutsi?”

“It doesn’t really burn your mouth,” Mma Makutsi replied. “It just tastes like that.”

“Same thing,” said Charlie.

Mma Ramotswe was eager to return to the business in hand. “Let’s not argue about such matters,” she said. “Everybody likes different things. We are not all made the same way.”

They were approaching the tea section, and Mma Ramotswe began to slow down, her attention drawn to a display of brightly coloured boxes of tea. “Now that looks very nice,” she said. “Perhaps—”

She did not finish. Charlie had seen something; now he abruptly reached out and clapped his hand over hers on the trolley bar. “There she is, Mma! There. Look.”

They stood quite still. At the end of the lane, on the point of turning the corner, was a woman in a shiny green dress, pushing a trolley laden with foodstuffs.

It was Mma Makutsi who broke the silence. “Violet!” she exclaimed. “Violet Sephotho!”

Mma Makutsi’s voice carried, at least as far as Violet, who spun round to find out who it was who had called her name. For a moment she appeared confused, but then, turning sharply on her heel, she changed the direction of her shopping trolley and began to push it towards the household products section. Mma Ramotswe lost no time. Leaning into the trolley, she began to pursue Violet, the trolley wheels clattering noisily as they picked up speed.

After a few seconds, Violet half turned to glance behind her. Seeing herself pursued by Mma Ramotswe’s advancing trolley, she spun her own trolley round the approaching corner. For a short while she was out of sight of her pursuers, but Mma Ramotswe was now assisted in the pushing of the trolley by Mma Makutsi and Charlie, and they began rapidly to close the distance between them.