Patrick Gale’s first historical novel is inspired by a non-story, a gap in his own family record. His great-grandfather Harry Cane spent the first part of his life as a gentleman of leisure among the Edwardian comforts of Twickenham. What then suddenly prompted him to abandon his wife and small daughter and emigrate to the Canadian wilderness? The official line was that he had money troubles, yet he doesn’t seem to have been short of cash in Canada.