The Shadow of the Object, the new novel from Mexican-American author Chloe Aridjis, opens with an eruption of violence: Flora, a fortysomething woman, is visiting her mother and stepfather in Mexico City for the first time in many years when one evening, as she is bidding them goodnight, Diego – the household’s beloved guard dog – springs up and sinks his teeth into her hand. This unexpected incident is an assault not only on Flora’s body, but also upon those delicate fictions that have, until now, shaped her life and swathed that body in an illusory sense of safety. The ageing alsatian, who had lived until the instant of the attack with “his inner life and ours mysteriously, harmoniously, aligned”, suddenly gazes up at the benevolent limb of his human benefactor and sees “an unsettling sight” indeed: “A hand out of context, unattached to a body … A hand gone rogue, no longer following orders from headquarters.”

Condemned to spend the rest of her vacation confined to the winding corridors of a private hospital in Mexico City, Flora is ambivalent. On the one hand, the environment is hardly stimulating – but on the other, “hospital stays offer a rare occasion to check out … as a patient you are absolved of most responsibility, nothing expected of you except to mend”. The hospital is life’s waiting room, and it is during a languid midnight stroll of its corridors that she meets Wilhelmina Blau, an elderly yet redoubtable German admitted with a bad case of pneumonia.

Flora and Wilhelmina strike up a friendship, and during their nightly meetings in the hospital’s dully lit hallways, Wilhelmina shares the ample wisdoms gleaned from her highly unconventional life. She tells Flora about her late husband and her son Max; she relates her childhood stays in a “preventorium” situated in what had once been a Cistercian abbey; she describes her favourite exhibit in Mexico City’s Museum of Anthropology (a human heart carved from greenstone, with “a face, eyes, eyebrows and fangs”, emitting “as much malice as the most sanguinary gods”). And – most consequentially – she describes for her new friend her now-dispersed collection of “pre-cinema toys and instruments”, once considered one of the greatest in the world: “shelves and shelves of magic lanterns and peep boxes, long mirrors that returned sideshow reflections, zoetropes and phenakistoscopes, shadow puppets in every corner”.

For Wilhelmina, the technologies of illusion illustrate “the persistence of vision … that human emotions are repeated, have but a finite number,” and “how the same gestures are repeated over the centuries in one vast theatre of the soul”. She hosts a magic lantern show in her room for the breathlessly admiring Flora and a gaggle of nurses; as images of glowing angels and overgrown gardens and robed magicians ravish the hospital’s sterile white walls, Flora and the nurses are utterly enraptured. Some days later, Wilhelmina succumbs to her illness, and it falls to Flora to return her belongings – including the magic lantern – and cremated remains to Wilhelmina’s son in London.

Leaving aside the profundity of its themes, The Shadow of the Object would be an immense achievement based on the strange, impressionistic beauty of its prose alone: mirroring Wilhelmina’s final magic lantern show, this slim and limber novella takes on an episodic structure as Flora returns to London and exchanges her burgeoning friendship with Wilhelmina for a hesitant sort of intimacy with her son.

Aridjis is concerned with those seams of enchantment that suffuse our daily reality, and how the metamorphic potential of images made from light might demonstrate that “no scene, no existence” is ever totally “self-contained”. Despite the weightiness of these ideas, her writing is deceptively pared back. In one scene, Flora and Max meet for a Sunday stroll on London’s New River Path, and Flora’s awareness of the history obscured beneath the cloudy water of the canal gives rise to a kind of ecstasy that the tidy marvels of Aridjis’s prose can only provoke the reader to share in:

To think that from this body of water containing soot and suicides and all other kinds of trauma, much of London used to drink. I sensed a hidden pact between everything, a density forced open in an instant. Winter branches wrote their foreign messages overhead. A blackbird. A wren. Birds who had stayed behind, not answering any migratory call … Yet the human species appeared to be obeying some sort of winter brief, and for a long stretch it was only the wind that walked ahead of us.

This is a fabulist’s novel, but one in which any gothic excess is tempered by a profound humanity. Nothing so workaday as a plot could be imputed to this glowing, mythopoeic book. But I can only concur with Aridjis’s many admirers that she is one of the boldest writers at work in English today.

The Shadow of the Object by Chloe Aridjis is published by Chatto & Windus (£16.99). To support the Guardian, order your copy at guardianbookshop.com. Delivery charges may apply.