Francis Spufford’s fabulous third novel is a piece of pulp fiction disguised as speculative history, or possibly vice versa: the tale plays both sides and switches lanes in a blur. It is set in an alternative 1920s America that is recognisable at the edges and unfamiliar at its core, centred on a First Nations people who have avoided the worst effects of manifest destiny to maintain a toehold of power in the febrile midwest. Where Golden Hill, Spufford’s riotous 2016 bestseller, took its lead from the writings of Henry and Sarah Fielding to paint a portrait of nascent 18th-century New York, Cahokia Jazz nods to the hard-boiled prose of Raymond Chandler and Dashiell Hammett. It rattles through the urban jungle in the manner of a fast-paced dimestore thriller.
Every good detective story is at heart a licence to roam – an excuse to kick open doors and interview all the suspects. So it is with Cahokia Jazz, which is at least as interested in the investigation of its constructed metropolis as it is in solving the murder of lowly, luckless Fred Hopper, who is found dead on a roof with his heart torn from his chest. The evidence suggests a ritual killing. Suspicion immediately falls on the Indigenous community. But Hopper, in addition to his day job as a clerk, was embroiled with the Ku Klux Klan and in debt to a bootlegger, and his death quickly points to a wider political conspiracy. Spufford’s invented city – built around the true-life Cahokia Mounds, near a village called St Louis – is a place of blind alleys and dark corners. It’s thick with mystery and in thrall to arcane tribal lore. The majority First Nations population holds sway but its position is tenuous: this utopia is revealed to be a tottering house of cards.
Our tour guide and proxy is headstrong, burly Joe Barrow, a mixed-race police detective who was raised as an orphan at a boys’ home in Nebraska. Barrow is conveniently new to Cahokia, still learning the ropes, and so it is via his dogged progress that Spufford draws his picture of a complex “mongrel city” in which fiction is grounded in historical fact. It’s March 1922, which means that Warren Harding is president, The Birth of a Nation is the KKK’s favourite film and Model-T Fords have the run of the road. But the US is here fighting Russia for control of Alaska while the “Mississippi Renaissance” plays as a kind of reverse Great Migration, funnelling African American factory workers back below the Mason-Dixon line.
Reconstruction, it’s clear, hasn’t bitten so fiercely in these United States, although the result is not so much a melting pot as an unstable pie chart of red, white and black influence. Spufford refers to these factions, respectively, as the takouma, takata and taklousa races. Officially, Barrow is working for the takata-dominated police department, but his physical appearance betrays his takouma origins and he finds himself increasingly beguiled by Cahokia’s First Nations leaders.
An overtly political writer might at this stage be laying the ground for a different breed of drama – a revisionist revengers’ tale, perhaps, in which an alliance of Native Americans and former slaves wrest control from their historic white oppressors. Spufford’s approach is more playful than prescriptive, more akin to that of an expert model engineer. He builds a world and paints the scenery, provides a physical map and useful background information, to the point where the act of creation becomes a story in itself. Cahokia, unavoidably, is a hotbed of racial and cultural tensions. But it primarily serves as an ornate film-noir playground; one that stirs memories of the alternative Alaska that formed the centrepiece of Michael Chabon’s The Yiddish Policemen’s Union.
Barrow (a headstrong romantic; your classic noir archetype) is fascinated by what he describes as “the city’s secret self”, suspecting that each neighbourhood hides a secret and every resident wears a mask. The detective, for his part, is as compromised and entangled as anyone else. He’s moonlighting as a jazz pianist and toiling to protect a wayward, rackety fellow officer. He’s hopelessly in love with a takouma princess and unwilling to believe that she might be implicated in the crime. Cahokia Jazz similarly has its hands full, gamely juggling exposition with action, the conjuring of a world with the demands of a machine-tooled murder mystery. Gears grind and wheels spin. Headlamps light the crime scene; pennies drop with a clunk. But the book’s route, although jolting, is rich with incident, texture and colour. Think of the genre plot as a tour bus; a handy mode of transportation. Spufford rides it through Cahokia and lovingly points out all the sights.
• Cahokia Jazz by Francis Spufford is published by Faber (£20). To support the Guardian and Observer order your copy at guardianbookshop.com. Delivery charges may apply