Belém was a city which resonated for Dyer. It was where one humid evening in an otherwise deserted riverfront restaurant he had stumbled across the police colonel who had arrested Ezequiel. The only other person in the Cantina da Lua was the waiter, Emilio Ribeiro, a lugubrious fellow who hurried for no one. A connection with Afonso Ribeiro, the first European to speak a native Latin American language, seemed highly improbable. Almost everyone in Bahia was called da Silva; most likely, the same held true for the Ribeiros of Belém. Yet it was a sign which the superstitious ex-journalist was reluctant to ignore. For Dyer, as for another ex-journo he admired, Graham Greene, coincidences were not merely spiritual puns, they ‘beset our past like the traps set for leopards in the jungle’. For most of his life, Dyer had considered extraordinary coincidences to be the lazy novelist’s gambit. Only since returning to Oxford had he started to recognise that it took an historian to set leopard’s traps.

Dyer perceived the waiter’s surname as an omen. For the first time in months, his life had taken on a new rhythm. He felt like the Portuguese admiral Pedro Cabral on the deck of his four-master, tossed upon boiling seas, his spanker sails buxom with a sudden wind from the south.

Shortly before 1 p.m. Dyer returned Professor Madrugada’s book to the stacks. Before unplugging his laptop, he checked the headlines. A mass extinction of antelope herds in the Russian steppes, allegedly linked to climate change … an Australian mathematician missing on a bush walk …

Dyer’s attention glided to the Middle East. The Iranians were protesting about the US president’s visit to Saudi Arabia and the Saudis’ purchase of $100 billion of US arms. Meanwhile, the latest US Defence Secretary was defining the three gravest threats facing America as Iran, Iran, Iran. Dyer wondered how Marvar would receive this news.

Outside struck the full winter chill of Oxford. There had been a frost in the night. The windscreens of the cars parked beside St Barnabas school stared blindly at him, opaque beneath membranes of ice. Dyer meandered back to Jericho through patches of mist, trying to recollect where he had parked his frog-green Beetle.

In the mist with his coat he was a bluster of dust. Dyer was halfway down Great Clarendon Street when he recognised Marvar leaning against the wall inside the entrance to the Oxford University Press. During the week, this was where smokers congregated – editors and managers discussing redundancies and bonuses, and – who knew? – Dyer’s book. This morning only three people stood sucking on their cigarettes, printers and shift-workers most likely, plus one solitary large flabby figure.

‘Rustum?’