“Borne” brings an acute intimacy to the tropes of genre fiction. Illustration by Keith Negley

Rachel, the twenty-eight-year-old narrator of Jeff VanderMeer’s new novel, “Borne,” lives in a harrowed, poisoned, semi-ruined city, where she scavenges scraps of food and tradeable detritus from the wreckage, a dangerous enterprise in a landscape haunted by the similarly desperate. Her lover and partner, Wick, remains holed up in their booby-trapped, warrenlike refuge, a former apartment building disguised as a midden. It’s essential that their home, a place they call the Balcony Cliffs, be unidentifiable from above, because their unnamed city is intermittently terrorized by a ravenous giant bear named Mord, and Mord can fly.

This is postapocalyptic fiction, a genre that, for all its lamentation over the loss of the world we live in now, often runs on a current of nostalgia for an earlier age. What is a zombie saga like “The Walking Dead,” if not a Western? Its premise replaces the civilization that makes our lives soft and easy with that most tenacious of American dreams: the frontier, where settlers get to reinvent society from the ground up and prove their worth in feats of manly valor. And, where the historical myth of the Western is now being eaten away by national guilt over the treatment of Native Americans, the zombie story provides us with the undead, a new category of nonhuman humans who can be mowed down without a twinge of conscience. The postapocalyptic imagination is shot through with unacknowledged wish fulfillment.

Not in VanderMeer’s hands, though. VanderMeer belongs to a loose group of literary writers, the New Weird, who bend the old devices of genre fiction to unaccustomed ends. His best—and best-known—work is the Southern Reach Trilogy, three novels published in succession, in 2014. The saga recounts the experiences of several people charged with investigating a stretch of coastal land where something uncanny has occurred. Within the borders of Area X, all human inhabitants have vanished, and the natural world has returned to its pristine state, without a trace of man-made pollutants. Much to the alarm of the authorities, the border of Area X is expanding. In a startling reversal, the world shaped by humanity—what one character describes as “dirty, tired, imperfect, winding down, at war with itself”—has been contaminated and invaded by purity.

Rachel’s city is the opposite of Area X. The river that rings it is a “stew of heavy metals and oil and waste that generated a toxic mist.” Not long ago, a shadowy operation known as the Company set up a biotechnology facility that cranked out freakish new organisms, then set them loose on the city’s streets to see what happened. Mord is the result of one such experiment, a creature manufactured to protect the Company from the increasingly restive locals. Now Mord runs amok, like the dragon in Spenser’s “Faerie Queene.” Many of the survivors have begun worshipping him as a god.

A bear the size of a department store given the power of flight: VanderMeer couldn’t care less about technological plausibility, and “Borne” isn’t, at heart, science fiction. With the toppling of the old forms of order, Rachel, Wick, and the other residents of the city have been plunged into a primordial realm of myth, fable, and fairy tale. Their world is a version of the lost and longed-for territory of fantasy and romance, genres that hark back to an elemental, folkloric past roamed by monsters and infested with ghastly wonders. Mord’s rival is a mysterious figure called the Magician, a woman clad in biotech robes that enable her to appear and vanish before Rachel’s eyes. The Magician’s minions are genetically altered children whose “iridescent carapaces” and “gossamer wings” recall Titania’s fairy attendants. In accord with Arthur C. Clarke’s famous dictum, the technology devised by the Company has become indistinguishable from magic, but this is not so much a midsummer night’s dream as it is a year-round nightmare.

Into this setting comes the novel’s title character, although whether he is a character or not isn’t clear at first. Combing for salvage in the dense fur of a sated, sleeping Mord, Rachel scoops up something “dark purple and about the size of my fist,” resembling “a hybrid of a sea anemone and a squid.” The thing emits a delicious fragrance of beach reeds and passionflowers, a scent that evokes a rare peaceful memory from Rachel’s nomadic childhood. “Much later,” she adds, ominously, “I realized it would have smelled different to someone else, might even have appeared in a different form.” First, Rachel treats the creature like a houseplant, then like a pet. Borne (so named because “he was born, but I had borne him”) gets bigger, while small objects and animals left around it disappear. It changes shape, pulses with color like a cephalopod to signal its moods. Whatever it is, Rachel finds it soothing and companionable. Then, one day, Borne speaks.

The conceptual elements in VanderMeer’s fiction are so striking that the firmness with which he cinches them to his characters’ lives is often overlooked. The primary characters in the Southern Reach Trilogy suffer from disorders of connection: one drifted away from the husband she loved; another comes from a family that for generations has been mired in the corrosive web of an intelligence agency. The vegetable invasion that threatens them seems so alien, in part, because it denies the detachment that modernity has made possible. “Borne” is VanderMeer’s trans-species rumination on the theme of parenting. “It” becomes “him.” Borne learns to read and to play. He asks the thousands of maddening questions familiar to any adult who has spent much time with a four-year-old (“Why is water wet?”) and many that are unanswerable for reasons peculiar to Borne himself (“Am I a person?”). Yes, it’s a bit creepy that Borne, for all his weirdness, has obviously been engineered to appeal to Rachel, but the same could be said of human babies, with their oversized eyes and adorable cooings. That Wick and Rachel might have had a child in the usual way doesn’t seem to have occurred to them. Along with all the tangible things that they have lost in their fall backward into the unchanging domain of myth, they have forgotten how to envision a future.

Wick mistrusts Borne, and Rachel’s refusal to give the newcomer up threatens the couple’s already doubtful alliance. No reader will blame her. As improbable a task as it may seem to make a faceless, squid-like creature lovable, VanderMeer does it. Children, their cuteness and their vulnerability notwithstanding, endear themselves by allowing adults to see the worn-out world remade through their eyes. When a protective Rachel grudgingly allows Borne on the balcony, and he gets a glimpse of the city’s deadly, multicolored, glowing river, he declares it beautiful. “I realized right then in that moment that I’d begun to love him,” Rachel explains. “Because he didn’t see the world like I saw the world. He didn’t see the traps. Because he made me rethink even simple words like disgusting or beautiful. That was the moment I knew I’d decided to trade my safety for something else.” To take on a child is to step out of fantasy and into history.

Compared with the Southern Reach Trilogy, which brings its readers, like its characters, to the threshold of the incomprehensible, “Borne” has a more conventional adventure plot. An epic confrontation will be forced, a quest undertaken, and secrets from the past unveiled, along with Borne’s true nature. The novel’s scope is of human dimensions, despite its nonhuman title character. But VanderMeer’s take on the postapocalyptic fantasy is not without subversive ambition. At its most regressive, the genre believes that we can truly become ourselves only when we are released from the constraints of a complex, denaturing society, when we’re allowed to live as we imagine our ancestors once did, and when we’re free to be who we really are underneath our overcivilized veneer. But in “Borne” the lawlessness of the city doesn’t provide survivors with a stage that has been cleared for heroic exploits. It’s merely Hobbesian: exhausting and degrading. The novel insists that to live in an age of gods and sorcerers is to know that you, a mere person, might be crushed by indifferent forces at a moment’s notice, then quickly forgotten. And that the best thing about human nature might just be its unwillingness to surrender to the worst side of itself. ♦