Jonathan Lethem’s breakthrough as a writer came from deconstructing the apparatus of the thriller and putting the pieces back together in unhinged ways. His Motherless Brooklyn won the National Book Critics Circle award in 1999 for exploding the most laconic of American archetypes, giving us a private detective with Tourette’s syndrome, a man who could never keep his sleuthing to himself.

Here he offers another, in some ways stranger, take on the genre. At first sight, in his beaten-up trailer on the eastern edge of Los Angeles, with his undressing stares and his severely rationed smiles, Charles Heist seems to be a private investigator from central casting. He keeps an opossum in a desk drawer. Lethem’s narrator, Phoebe Siegler, stumbles in on Heist to help her search for a friend’s missing daughter. Siegler has resigned her editorial post at the New York Times, over what she viewed as its appeasement of the incoming 45th president. She has headed to California both for an escape from “the beast in the Tower” – it is the month before Trump’s inauguration – and in the hope of a quest that will make her feel like a journalist.

She has pitched up in Heist’s rank trailer because her only lead in her hunt for the missing student, Arabella Swados, is their shared love for the songs of Leonard Cohen. She knows Arabella has been shaken by the singer’s death and believes she may have come on a private pilgrimage to the Buddhist retreat at Mount Baldy in which he once lived. Charles Heist’s ramshackle “practice” is at the foot of that mountain.

What follows is less a missing person drama than a wayward road trip into off-grid America. Lethem wants to make his book an allegory for all the red-in-tooth-and-claw division and the deranged politics of the nation. Siegler – a naive and not always convincing voice – is torn between two icons: she can’t decide whether she wants to be Nancy Drew or Joan Didion. She ends up, self-consciously, in the degraded world prophesied by the latter in that seminal book on the fallout of the Californian 1960s, Slouching Towards Bethlehem.

In his pick-up truck Heist takes her into a ravaged landscape of post-hippy tribes and drug communes, of which he himself is a survivor. These tribes, it seems, over the years, have coalesced into two groups: the Bears, a violent death cult of sometime Hell’s Angels, and the Rabbits, a mutually supportive post-feminist community of female avengers. Arabella is caught up in these warring visions of the frontier, like a kidnapped governess tied to a tree in a western. Naturally, only Charles Heist can save her.

Lethem is a fearless kind of writer, and he takes all sorts of high-wire risks here, some of which come off enjoyably, some of which fall to earth. In trying to create a telling myth of the American present he indulges comic-book hyperbole. The King of the Bears is a hairy individual named Solitary Love, a sort of stand-in for the “rough beast” then about to be anointed in the White House: “He wore a bearskin costume that flapped around his shoulders, bound with straps across his chest, and nothing underneath. His shadowy junk swung heavily as if he were never less than slightly aroused.”

In Solitary Love’s orbit, out in the desert, Siegler comes upon a ring of 4x4s and trailers shored up against the wind, like pimped-up covered wagons: “Ordinary people might be the most terrifying thing on earth,” she observes. “Or ordinary Americans, I should say. For months now I’d studied them in the backdrops of the ceaseless television rallies, stacked in those vertical arenas revering the back of a blue suit and a red hat, trying to fathom what they see in him, and wondering where they went to, after…” It seems that they pitched up here, on the edge of the apocalyptic wilderness, one half of the warring factions of America’s psyche. The resultant conflict is predictably bloody – “It was all kind of Game of Thrones actually,” remarks one onlooker – and, in what reads like a fearful private cage-fight with the extremes of the American present, redemption is far from certain.

• The Feral Detective by Jonathan Lethem is published by Atlantic (£16.99). To order a copy go to guardianbookshop.com or call 0330 333 6846. Free UK p&p over £15, online orders only. Phone orders min p&p of £1.99