They had met at a party in the Museum of Tomorrow in Guanabara Bay. The blurry glaze of her eyes. The sheen of her voice. Nissa could begin a sentence in Brazilian and end it in French or English, and flirt in all of them. Undefended, Dyer went home with her after they ran into each other again at a photo exhibition of Peru’s Sendero years. Within weeks they were living together in his rented flat off Ipanema.

She gave birth to Leandro fifteen months later. After what had happened to Astrud, Dyer had folded himself tight, refusing to invest in a miracle, until one eyelid quivered open, then another, and two bottomless pupils of midnight blue stared out for the first time, and, appearing to focus, saw a middle-aged man who had started to sob.

Yet the arrival of Leandro did not fulfil Nissa.

Nissa had a short attention span if it didn’t involve her. A baby was a competitor. Leandro was four when she left Dyer for an English lawyer, Nigel Trenchpain.

Dyer’s despair was transparent, colourless.

‘I thought she was different,’ he told Vivien.

‘Hardly anyone is, my dear.’

‘Oh, Vivien,’ he said. ‘Oh, Vivien.’

‘It’s OK,’ she held his head. ‘It’s OK.’

Following a brief and unexpectedly straightforward tussle, he gained custody of his son.

Leandro had his mother’s deep laugh and mameluco eyes, like antique glass, and his father’s unsettling persistence. Weaned off the quick fix of journalism, Dyer flexed his stubborn streak to safeguard his independence. The BBC and then The Economist approached him to be their stringer, but he declined. Dyer’s life concentrated on his son.

His days freed up once Leandro began attending the nursery school opposite. While hysterical presidents battled with impeachment, Dyer spent his mornings giving English lessons to wealthy clients; his afternoons teaching glue-sniffing orphans how to read and write.

At what point did it dawn on Dyer that God might have been Brazilian once – as Dyer had believed on arriving in Rio thirty-three years earlier – but had since changed nationality? It was a culmination of separate incidents more than any abrupt revelation, and stole up on him like the subject for his next book. Beneath the art-deco arms of Christ the Redeemer, a street kid was being killed every other week in Dyer’s favela. Drugs and flick knives were discovered in two satchels at Leandro’s new school. Even the beaches had started to stink.

Rio. It had become true for him. A great city – a great solitude.

Over a cold and suddenly tasteless lager in his local bar on Joaquim Nabuco, Dyer was ambushed by an occult feeling that he needed to get Leandro out of Brazil before his son got a blade in his abdomen, or Dyer did. In the five years since she had walked out, Nissa’s new life had left her no space for Leandro, and so it was up to Dyer to act.