The tale travels, with Leah and the submarine, down through the missing six months and the ocean’s vertical zones (sunlight, twilight, midnight, abyssal, hadal), while on land Miri tracks how their relationship is changing in the present. It is told in two alternating voices: Leah’s, in the form of a journal she kept on a deep-sea dive that stranded her and two others in undersea darkness and that of her wife, Miri, who presumed her lost, after Leah’s return. Her debut novel, Our Wives Under the Sea, takes this watery theme, adds it to the kernel of another of her stories (Cassandra After, in which the narrator’s girlfriend returns from the dead), and expands. There is a sense that in this new reality, where whirlpools are “teeth in the ocean”, and the creatures of air and sea are growing “monstrously outsized”, humans are regressing to prehistoric beginnings. The world shrinks, to “lambent pupils on the water”, the “enterprising tentacles” of octopuses, their “liquid squeeze”. The collection ends with the extraordinary Salt Slow, in which a man and a pregnant woman find themselves in a small boat on an ocean that has drowned everything they know – a conceit that reaches both forward, to the predicted effects of climate change, and back, through Noah’s flood to creation.

Armfield is extremely good at anatomising the women’s relationship – the small moments of which lasting love consists The effect is only heightened by a deliberate, vivid realism of place (Newport, Manchester, Glasgow rented flats, bars in university towns) and a discerning interest in the shifting power structures of relationships. It is tricky to describe what happens without giving away the endings – which, when you become used to her method, are often prefigured in the beginnings, and in the classical tales her literalism both defamiliarises and renews: wolf-siblings, maenads, a gorgon.

So a convent schoolgirl with problem skin, always shedding and peeling, undergoes a metamorphosis or a town fills with Sleeps, each having stepped out of its owner “like a passenger from a railway carriage”. Choose a quotidian phenomenon – problem skin, say, or sleeplessness – and use it as a foundation stone for relentlessly logical, haunted edifices reminiscent of the contemporary gothic of Mariana Enríquez or Guadalupe Nettel. J ulia Armfield’s first book, a collection of stories called Salt Slow, set out a method.

Our wives under the sea