Mma Makutsi frowned. “At the Botswana Secretarial College we were taught never to throw anything away for at least a week,” she said. “There might always be some follow-up.”

“There will be no follow-up to a letter of thanks,” said Mma Ramotswe. “That is it. There will be no more. That case is closed.”

With a slow show of reluctance, Mma Makutsi held the letter over the bin and dropped it in. As she did so, the door of the office opened and Charlie, the older of the two apprentices, walked in. He had removed his work overalls to reveal a pair of jeans and a tee-shirt underneath. The tee-shirt, Mma Ramotswe noticed, had a picture of a jet aircraft on it and the slogan underneath in large letters: HIGH FLIER.

Mma Makutsi looked at him. “Finishing work early today?” she asked. “Ten o’clock in the morning? You’re a quick worker, Charlie!”

The young man ignored this comment as he sauntered over to Mma Ramotswe’s desk. “Mma Ramotswe,” he said. “You’ve always been kind to me.” He paused, casting a glance over his shoulder in the direction of Mma Makutsi. “Now I’ve come to say goodbye. I’m finishing work here soon. I’m going. I’ve come to say goodbye.”

Mma Ramotswe stared at Charlie in astonishment. “But you haven’t finished your…your…”

“Apprenticeship,” supplied Mma Makutsi from the other side of the room. “You silly boy! You can’t leave before you’ve finished that.”

Charlie did not react to this. He continued to look at Mma Ramotswe. “I haven’t finished my apprenticeship—I know that,” he said. “But you only need to finish your apprenticeship if you want to be a mechanic. Who said I want to be a mechanic?”

“You did!” shouted Mma Makutsi. “When you signed your apprenticeship contract, you said that you wanted to be a mechanic. That’s what those contracts say, you know.”

Mma Ramotswe raised a hand in a calming gesture. “You needn’t shout at him, Mma,” she said quietly. “He is going to explain, aren’t you, Charlie?”

“I’m not deaf, you know,” said Charlie over his shoulder. “And I wasn’t talking to you anyway. There are two ladies in this room—Mma Ramotswe and…and another one. I was talking to Mma Ramotswe.” He turned back to face Mma Ramotswe. “I’m going to do another job, Mma. I am going into business.”

“Business!” chuckled Mma Makutsi. “You’ll be needing a secretary soon, I suppose.”

“And don’t bother to apply for that job, Mma,” Charlie snapped. “Seventy-nine per cent or not, I would never give you a job. I’m not mad, you see.”

“Ninety-seven per cent!” shouted Mma Makutsi. “See! You can’t even get your figures right. Some profit you’ll make!”