The nurse shook her head. “There has been nobody. The last patient was that man last week—the one who had the motorcycle accident near Pilane. He got better quickly.” She turned to Mma Ramotswe. “Every time I see a motorcyle, Mma, I think of the young men we get in here…” She shrugged. “But they never think of that. They don’t.”

“Young men often don’t think,” said Mma Ramotswe. “They cannot help it. That is how they are.” She thought of the apprentices, and reflected on what a good illustration they were of the proposition she had just made. But they would start to think sooner or later, she told herself; even Charlie would start to think. She looked at the bed, covered in its neat white sheet. Although the sheet was clean, there were brown stains on it, the stains of blood that the hospital laundry could not remove. At the top of the bed, to the side, she saw a machine with tubes and dials on a stand.

“That is a ventilator,” said Tati Monyena. “It helps people to breathe. All three patients…” He paused, and looked at Sister Batshegi, as if for confirmation. “All three patients were on it at the time. But the machine was thoroughly checked and there was nothing wrong with it.”

Sister Batshegi nodded. “The machine was working. And we checked the alarm. It has a battery, which was working fine. If the machine had been faulty we would have known.”

“So you can rule out a defective ventilator,” said Tati Monyena. “That is not what caused it.”

Sister Batshegi was vigorously of the same mind. “No. It is not that. That is not what happened.”

Mma Ramotswe looked about her. One of the patients at the end of the ward was calling out, a cracked, unhappy voice. A nurse went over to the bed quickly.

“I have to get on with my work,” said Sister Batshegi. “You may look round, Mma, but you will find nothing. There is nothing to see in this place. It is just a ward. That is all.”