To describe Kris Kneen’s latest novel as “sexy” would be an understatement. The sensual, sometimes disturbing Rite of Spring redraws the limits of sex, desire and the body in bold new ways, and Kneen isn’t afraid to lean into the details.

The novel features only two human characters – Miranda and Richard, who have signed up for a six-month stint as lighthouse carers on a remote island off the coast of Tasmania. The pair hope to reignite their failing marriage away from civilisation, where Richard had been unfaithful with a woman whose spectre still haunts any intimacy between them. Miranda, a marine biologist, is also recovering from a diving accident that severed her connection to the ocean, the only place she’s felt truly herself.

Isolated on the freezing island, “one of the windiest places on earth”, they are hoping to rediscover what they’ve lost. But it awakens a deep sense of unease in Miranda, who has felt uncomfortable in her body since the accident and the onset of menopause. She finds herself drawn to the unknown and to the possibilities of who she might become in this new place.

She remembered her excitement in the days before a dive. And if anyone had asked her what she was looking for down there in the deep water, she would have stared out into the future with that same unfocussed expression.

Miranda’s search for something “huge and pure” in the ocean’s depths is a yearning that compels her. She’s the real star of this novel and it’s her sexual, physical and psychological awakening that reader and writer are invested in. Richard is mostly one-dimensional. His infidelity hangs between them but isn’t presented as unforgivable, so he comes across as an affable, slightly overprotective carer, whose purpose in the role of “husband” Miranda envies – particularly given how awkward she finds the more passive, feminised role of “wife”. His lack of curiosity sits in stark contrast to Miranda, whose eagerness to explore the possibilities of this new environment is obvious before she even steps off the boat. She soon uncovers a series of unsettling effigies, made distinct by their grotesque faces and non-binary genitalia.

Although the figures make Miranda uneasy at first, when she finds the journal entries scribed by their creator – the mysterious KJ, whose sections of the narrative are marked by her desperate plea to be saved from her own “wretched desire” – something in her body responds. Sex seeps into all corners of the narrative, and Miranda chases it, desperate to discover the truth of herself and to reconnect with her own desire.

The alien depths of the ocean offers possibilities for the body beyond the gender binary – female octopuses able to impregnate themselves; the permanent, almost violent union of the anglerfish; parrotfish able to change their gender at will. Miranda dreams of “fins and flaps of skin hiding complicated genitalia”. Kneen exploits the ocean’s hidden potential gleefully and, as Miranda begins to more boldly explore the island and its surrounding waters, the ocean begins to offer up its secrets, leading her to discoveries about her own body as well as the bodies that call to her across the waves.

The challenge this novel poses to the body is less about its limits and more about its potential. In addition to KJ’s diary entries, the narrative is interrupted by a number of personal reflections signed by “Kris”, which read like dispatches from the future and connect the two characters – KJ and Miranda – to the author’s experience of being non-binary. Where KJ fears her unconventional desires, Kris embraces them; Miranda is on the precipice of the two.

Kneen has used their body as a site for story before, particularly in their memoir Fat Girl Dancing. But their fiction is more tightly crafted. There is abundance in the language they use to describe the experiences of the body but the focus is sharp and the dramatic tension soars. The isolated island is moody – electric storms, fallen trees, icy and powerful wind – and the possibility of things going horribly wrong is never far away. But the ocean and the life within it is a refuge, painted exquisitely and often erotically in the language of sex and the body; the pink flesh of Australian salmon “as wide and thick as a vulva”, for instance.

There have been parallels drawn between Rite of Spring and Shakespeare’s The Tempest but there are more interesting comparisons to be made. There are echoes of Margo Lanagan’s eerie, Stella-shortlisted Sea Hearts, which brings together the myth of the selkies with questions of power, bodily agency and transformation; as well as more contemporary novels exploring the peri- and post-menopausal body, including Miranda July’s All Fours. Which of these threads resonates depend entirely on what the reader brings to the page. Rite of Spring is a surreal, sexy triumph.

• Rite of Spring by Kris Kneen is out through Transit Lounge