On the first morning of their holiday together in a remote part of Scotland, 42-year-old Sarah convinces her younger sister, Juliette, to clamber on to the roof of their mobile home for a better phone signal. Juliette has three layers of tinfoil wrapped around her limbs and a tinfoil cone hat plonked on her head before she clocks that she’s fallen for a prank. It’s a pleasing bit of sibling slapstick in Slags, the new novel from Emma Jane Unsworth about desire, dissatisfaction and the ferocious loyalty of sisters. And sisterhood, as Unsworth writes it here, is an unbreakable connection for which no prank antenna is needed.

When Sarah takes Juliette on a Highland road trip for her birthday they find themselves revealing secrets and reckoning with their younger selves. Candid and comic, Slags is Thelma & Louise with a campervan and without a clifftop. There are shades of Fleabag, too, in the fractious sisters, the sexual escapades of one countered by the suburban righteousness of the other.

The novel focuses on Sarah, with chapters alternating between her teenage self, obsessing over a teacher in a desperately pining first-person confessional, and the adult woman, who puzzles over the percolations of midlife desire (narrated by an older, omniscient authorial voice). The present-day Sarah is single, sardonic, bored with sobriety. She lives in London, where no one seems to party any more and “everyone was thinking about their gut health, or their crochet, or the state of the economy”.

Juliette, by contrast, is married with children, and lives in Manchester. Her husband, Johnnie, is into ice plunges and Andrew Huberman podcasts. Unsworth is especially merciless in her portrait of a particular kind of modern masculinity, captured here in all its absurdity. “Longevity seemed pointless,” Sarah reflects, “when you were as tedious as Johnnie.” Johnnie doesn’t have much of a role in the novel, but it’s often through the minor characters, those merely glanced at in the rear-view mirror, that Unsworth demonstrates the sharpness of her perceptions.

Deanna, Sarah and Juliette’s mother, for instance, only periodically swings into view. She is a fleeting memory of neglect – abandoning her young daughters on a broken-down train, stumbling into a party humiliatingly drunk – but Unsworth allows her to cast a long shadow. Later, Sarah reflects more forgivingly on her mother’s abortive efforts to escape suburban life and “the stocks of domesticity”. Suburbia, in general, is efficiently demolished here, reduced to “bin wars, magnolia tree one-upmanship, brick drives, chest freezers, double garages, weedkiller, Chicken Tonight in Le Creuset, Laura Ashley in perpetuity.”

Sarah wants none of it, but her job and her life in the city also leave her empty. Unsworth describes how “late at night, after video calls with the East Coast of America, she often stayed on as a host, alone, in those abandoned Zoom rooms, her own face staring back at her, the glow of the ring-light as hygge as any wood-burning stove, sipping a glass of something moderately alcoholic, feeling a dystopian peace …” It’s not quite loneliness, more a beautiful desolation. “I don’t want to sort my life out,” she tells Juliette during a heated drunken argument. When Juliette protests “But you feel bad”, she replies: “Only sometimes …”

One of Sarah’s distinguishing qualities is this lack of clarity about what it is that she desires. She belongs, as she explains, to gen X, that “lost generation”, too young to be old, too old to be millennial, sexually liberated and yet still searching for something. Where Unsworth captured the erratic hedonism of twentysomethings in her 2014 novel Animals and the online dysfunctions of thirtysomethings in 2020’s Adults, here she plumbs the muddles of midlife. Sarah is a rare female character: she’s not a mother, but neither is she full of fraught questions about fertility or menopause. She is, instead, frank about “getting her rocks off” and the difficulty of how to do that without the aid of drink or drugs.

How to contend with sexual desire is a question for the 15-year-old Sarah, too. She shrugs off unhappy sexual encounters, including an experience of indecent exposure, with a swaggering bravado. How that shapes the adult Sarah’s attitude to sex is not straightforward, and there’s an intelligence in Unsworth’s refusal to present clear cause and effect. Comedy, rather than tragedy, is the response she most often prefers. Perhaps this is symptomatic of the Fleabagification of women’s stories – where farce somehow feels more truthful than straight-up trauma. Is comedy a deflection or a pragmatic approach to getting on with things in a world of misunderstanding and confusion? Certainly, Slags culminates in a confrontation that is more chaotic than climactic. But this is an undeniably fun read, the levity often lifted by an underlying sense of sympathy, affection and tenderness. Unsworth is riotous, rewarding company.