Walker is a D-Day veteran with post-traumatic stress disorder; he can’t return home to rural Nova Scotia, and looks instead to the city for freedom, anonymity and repair. As he moves from New York to Los Angeles and San Francisco we witness a crucial period of fracture in American history, one that also allowed film noir to flourish. The Dream had gone sour but – as those dark, classic movies made clear – the country needed outsiders to study and dramatize its new anxieties.

While Walker tries to piece his life together, America is beginning to come apart: deeply paranoid, doubting its own certainties, riven by social and racial division, spiralling corruption and the collapse of the inner cities.