“Ratchet Clark lived with her mother, Henriette, in a small, gloomy sub-basement apartment in Pensacola, Florida. They had no windows, but if they had she imagined they would be able to see worms, grubs, and strange scary insects. There would be larvae eating the corpses that people had snuck into the apartment yard to bury under cover of night.” These are the opening lines of Polly Horvath’s new novel, The Canning Season, and they radiate a sense of entrapment and mirthlessness, which suffuses much of the book. The novel’s glum cover pretty much nails the mood of the book dead on.

Not surprisingly, adolescent Ratchet is having a miserable life. Her mother “always made her come home right after school because she didn’t want to pay for after-school programs and didn’t like the idea of her making friends.” So Ratchet spends most of her time alone and underground while her mother cleans other people’s houses, and waits on tables at the classy Hunt Club.

Ratchet’s very name, her windowless home, her neglectful mother’s pathological craving for membership at the Hunt Club all create a hyper-Dickensian milieu that is difficult to take seriously. We dismiss it as unreal, and since we can’t take the characters seriously, it’s very hard to start caring about them. Horvath has written about unlikely characters before: Witness the irrepressible Primrose Squarp in her last, opalescent novel, Everything on a Waffle. But there, the tone was so much more humorous and vital, and carried off with a wonderful character and her first-person narration. Here, Horvath chooses a third-person narration in which the cowed Ratchet barely seems to exist.

With less than no ado, Ratchet is dispatched to rural Maine to spend the summer with two very distant relatives (great-aunts for lack of a more precise term), twin spinster sisters called Penpen and Tilly. They live by themselves in a palatial house in the middle of bear-infested woods, and have had decades to become very odd. This development seems to promise a release from the bleak claustrophobia of the opening pages. Alas, no.

Far from blossoming, Ratchet seems to wither away altogether, and small wonder. She is completely overwhelmed by her two eccentric aunts, who suck most of the oxygen out of the house – and narrative – with their endless talking and reminiscing. Characters telling lengthy stories have always played a large part in Horvath’s fiction, but too many stories can have an enervating effect. Though the stories from the aunts’ past are diverting, they starve the narrative of forward momentum. With relatively little happening in the present tense, Horvath’s story stalls. After a while you feel as if you’ve been trapped too long with crazy Miss Havisham in her lightless room, and want to run screaming for the door, window, or air duct – whichever’s handiest.

Some fresh air does get pumped into the story with the arrival of the obnoxious Harper, a 14-year-old girl whose caregiver dumps her at the aunts’ after mistaking it for the local orphanage. Penpen, a recent convert to Buddhism, is unable to turn anyone away, so Harper stays. These four oddball characters form a most bizarre constellation: initially, their interactions are distant and oblique, but then, amazingly, they start to form a tighter orbit of mutual need and even real affection. It’s a testament to Horvath’s powers as a writer that she can even get such bizarrely disparate characters into the same room and scene.

But she is only partly successful. With Harper’s arrival, Ratchet seems to fade into the background even more, often not speaking or even being referred to for pages at a time. Indeed Harper all but supplants Ratchet. She is louder, more assertive, and frankly more sympathetic as a character. Ratchet really doesn’t start emerging until halfway through the novel, and by then it’s too late: as readers we’ve been plopped into this quagmire of a world without benefit of a strong character to guide us, and we’ve given up on Ratchet. She just wasn’t there when we needed her. By novel’s end, when Ratchet finally seems to emerge from her shell, it almost escapes notice, because it seems to happen off the page. What’s more, it’s hard to believe in – or care about – this transformation when Ratchet’s starting point was so unreal and over-the-top.

Other interesting incidents are sprinkled through the novel. Penpen has her first heart attack; Harper’s caregiver (actually her pregnant aunt: another bizarre character) keeps coming back to retrieve her, then changing her mind and dumping her again; and Ratchet’s mother comes to pay a visit with her new, much younger boyfriend. Hutch, a tennis coach at the revered Hunt Club, was ostensibly the reason Ratchet was evicted from her unhappy home for the summer. Henriette is desperate to impress him and thinks Ratchet is a liability.

But these happenings seem pieces of an eccentric mosaic, rather than a chain of incidents that develop the characters and plot. By novel’s end, Ratchet and Harper decide to stay on with Penpen (Tilly has died) and find happiness, or at least contentment in their own idiosyncratic ways. An epilogue follows them into adulthood.

Horvath is a skilled observer of human nature with all its foibles, and has a keen eye for moments of understated absurdity, tenderness, and nobility. She can be funny, although in this book, her humour runs too often to the dark and grotesque for my liking. Often her characters reveal hidden depths (the brash Harper’s love of gardening, for instance) and, as with Horvath’s previous books, there’s an emphasis on accepting people as they are. Tolerance is next to godliness in her world. But in The Canning Season, Horvath may be asking us to tolerate a little too much dreariness and inertia. If only Primrose Squarp had whirled onto the scene like a Tasmanian devil, and revved things up a bit.