There is, inevitably, a sense of loss that Ali Smith’s seasonal quartet (lengthened into five books by 2022’s Companion Piece) is now over. These novels, as close to livestreamed literature as the technology would allow, were each masterful works of deeply moral writing; together, they built into something like a handbook for life in the 21st century. Gliff, her follow-up, takes the logical next step from these up-to-the-minute novels and is set in a dystopian near future. The story is narrated by Bri, a characteristically precocious and logomaniacal Smith avatar, non-binary and in their early teens when the novel opens. Bri and their sister, Rose, find themselves alone and unwelcome in a more-or-less identifiable Britain when a family emergency calls their mother away.

Bri and Rose are “Unverifiables” – a subclass in a culture that has taken the hostile environment to dreadful extremes. It’s not clear whether they are excluded on grounds of nationality, race or because, as a result of a headstrong and idealistic mother, they have not submitted to the model of surveillance capitalism that dominates the country. Their mother thinks smartphones are “liabilities”: “a device that means you see everything through it.” The government has imposed a system whereby the homes of Unverifiables are painted around with red lines, then bulldozed. Bri and Rose are on the run from a force that is both faceless, terrifying and banal in its relentless bureaucracy.

The origins of this totalitarian landscape are never fully mapped out; the reader is left – quite deliberately, I think – to fill in the blanks. This is the logical evolution of the world Smith presented in the seasonal quartet: of brutal detention centres in which a for-profit security firm (“SA4A”) processes and renders human beings with a deliberate effacing of their individuality. The way those who find themselves on the outer edges of our society are treated has always been a signal theme of Smith’s work. In the dystopia of Gliff, not only is the government seeking to control and exclude those it deems undesirable; the fissures in society have become so wide that the rich seem not even to see the poor. “It was like they all had their backs to me, even the ones facing me,” Bri says. “Their disconnect was what elegant meant.”

There is a kind of caesura halfway through the book, when a new chapter begins with the words “Brave new world”. We move forward five years to find Bri is a factory supervisor in a world that has become even bleaker and more technocratic. Child workers on the factory floor are scarred and mutilated, burnt by battery acid, living under the boot of a remorselessly productive state. As the chapters progress, we find variations on the theme of Brave New World: “rave new old”, “rave n o (us)”, “ave n (i) r”… With each subsequent chapter, with each of Bri’s small rebellions, we understand what it takes to challenge totalitarianism, to pick it apart, thread by thread. A character from Bri’s past appears and sets in process a chain of memories and events that propel the narrative towards its hopeful ending.

The title of the book refers to a horse that Bri and Rose encounter in a field near their house. He is called Gliff, a name that Bri, who loves words, tells their sister is “polysemous”: having many meanings. “Because of what you called him,” they say, “he can be everything and anything.” The horse becomes a metaphor for the care we show to others, even those whose perspectives we do not share. “Was a horse more lost to the world,” Bri wonders, “because of no words, or was the horse more found – or founded…?”

In the end our hope lies in Bri and Rose, in their generation, in outsiders. And if Smith’s recent books were a handbook for 21st-century life, Gliff is a warning as to what will happen if we ignore their lessons.