Catching the trout was only part of it, though. Fishing sharpened your memory and perception, and allowed you to see connections that might otherwise have drifted by unnoticed. Later, Dyer carried its lessons into journalism. As a cub reporter, he discovered that almost everything about fly fishing, from his selection of a fly to his method of casting the line, had this in common with a line of prose: it could not hide his character – although, paradoxically, everything condensed towards trying to suppress that character.

Above all, he learned that even the smallest grayling lifted flashing from the water could stand as a true image, a true sentence, the scrap, as it were, of a greater truth. A muscle of light and agitated life that connected the angler to the universe.

Athough he kept his father’s rod in the hall as a standing reminder of something he intended to do, Dyer had not fished in England for years. He had fished the Piabanha near Petrópolis, the Paraná further north, and the Amazon – from sturgeon-sized peixe, whose each pearly scale was the size of a woman’s purse, to tiny blue hatchet fish, as if a kingfisher had dived underwater and shattered. But he had hardly picked up a rod since Astrud’s death, and not once to fish with a fly.

He hesitated over an elk-hair caddis before selecting a white Klinkhammer, and tied it on. As on his last outing to the Hodder, he squirmed along the bank: this impatient, messy, blind, noisy form a crushing argument in his own person against the qualities needed to catch a fish. His aim this afternoon was simple, as when he first came here as a teenager. To untangle himself into becoming what normally he was not. And so achieve that meditative state in which his mind was carried forward by the flow of the stream – until it was both cleansed and primed to make connections; to strike, to hook.

He stood on a rock and cast upstream. It was difficult to distinguish his white Klinkhammer from the bubbles and foam. He had to raise the rod and drag the fly back so that it lay on the surface. ‘The secret is concentration. Brain, muscle, ear, eye have to have coordination. You can’t teach that.’ Among the superstitions that his father had passed down was his belief that fishing was about concentrating on the fly until it took you into another world.

Dyer cast again, like a prayer. With every cast he was dropping a line into the unknown in order to reach out and connect. Until the moment arrived when, instead of a white dot bobbing between chevrons of rippling water, he is conscious of an eye measuring him.

He stares back. This eye – impassive, matter-of-fact – evaluates him for what he is, and not for any secret he might have concealed in a library book. Rougetel lifts the candle to her face.