The Limpopo was not very wide at that point, but the central channel was deep, a place for a predator. The man was halfway across, seated in his boat with its small outboard motor, when a large crocodile had reared up out of the water and snatched him by the shoulder, dragging him into the river. The herd boy, who was with him in the boat, watched as it happened. At first he was not believed, as crocodiles very rarely attacked a boat, but he stuck to the story. They found what remained of the farmer eventually, and the herd boy was shown to be right.

She looked at the water. It was easy for a crocodile to conceal itself close to the edge, where there were rocks, clumps of half-submerged vegetation and lumps of mud breaking the surface. Any one of these could be the tip of a crocodile’s snout, protruding from the water just enough to allow him to breathe; and, a short way away, two further tiny islands of mud were really his eyes, fixed on potential prey, watching. We are so used to being the predator, thought Mma Ramotswe. We are the ones to be feared, but here, at the edge of our natural element, were those who preyed on us.

Further out, a kingfisher hovered and then plummeted, stone-like, into the water; a splash of white spray, and then up again to a vantage point in the air. She watched this for a few moments, and smiled. Everything has its place, she thought; everything. And then she turned round and made her way slowly back up the track towards the van, to await the arrival of Mma Potokwane and the children. She thought she could hear an engine now, straining somewhere not too far away. That would be one of the orphan farm’s minibuses, nursed and kept alive by Mr. J.L.B. Matekoni, officially retired by Derek James, who ran the orphan farm office, and replaced with something newer, but brought back by Mma Potokwane, who could not bear to waste anything. The old minibuses were now used for work like this, since Mma Potokwane did not like the thought of the newer vehicles destroying their suspension on these bumpy roads.

There were two familiar old blue minibuses. The first one, driven somewhat erratically by Mma Potokwane, drew up close to where Mma Ramotswe was standing and the matron herself got out. She opened the rear door and a chattering group of children spilled forth.

Mma Ramotswe made a quick mental count. There had been nineteen children in a vehicle made for twelve.