Mma Ramotswe inclined her head; it was a reasonable point. “Yet Susan is also a common enough name, Mma. So what if there were many Susans at the time—and many Rosies? Would it not be possible that one of these Rosies might have looked after a Susan—but a different Susan?”

Mma Makutsi gave her a doubtful look. “I do not think so, Mma. Oh no, I do not think so at all.”

“Well…,” began Mma Ramotswe.

But she did not finish. The first of the Rosies had made an appointment and there was a hesitant knock on the door.

“The first of the liars,” mouthed Mma Makutsi.

Mma Ramotswe gave her a discouraging look, but said nothing. It would have been too late to do so, anyway, as the office door was now being pushed gently and she saw, peering into the room, a tall woman in a green dress.

“This is the No. 1 Ladies’ Detective Agency?” asked the woman. She spoke with a rather strange, guttural accent, as if she were not a native speaker of Setswana, or of English.

“It is,” said Mma Ramotswe. “And you must be Rosie.”

She gave the woman a considered look. Did she resemble the woman in the photograph? It was hard to tell, because of the image’s lack of definition, but it was just possible that this woman’s head was the same shape as that of the woman in that blurry photograph.

The woman seemed to hesitate before she replied. Only for a moment or two, but it was long enough for Mma Makutsi to notice and to flash a warning glance in Mma Ramotswe’s direction. The meaning of this glance was clear enough—at least to Mma Ramotswe. It was: she had to remind herself that she was claiming to be Rosie.

Mma Ramotswe was less ready to jump to that bleak conclusion. People can be hesitant for all sorts of reasons, she felt—unfamiliar surroundings, social awkwardness, lack of confidence: all of these could explain a brief hesitation in answering.

“Yes,” she said. “I am Rosie.”

Mma Ramotswe invited her to sit down. She offered to make tea, but Rosie declined. As she settled herself in the client chair, Mma Makutsi started to quiz her.

“You read the article?” Mma Makutsi asked.

“I did,” said the woman. “That is why I am here.” She paused, and then continued, “I’m sorry, Mma, but could you tell me who you are?”

The effect of this question on Mma Makutsi was dramatic. Straightening her back, Mma Makutsi sat bolt upright, her lips pursed, her fingers intertwined. “You’re asking my name, Mma?” she said. “Is that what you’re asking me?”

“If you don’t mind, Mma.”