Gemma (Imogen Poots) isn’t the sort of person who envisions herself leading a banal, button-down life in suburbia. Granted, not much is revealed about her background in the opening scenes of Lorcan Finnegan’s twisted sci-fi/horror allegory Vivarium. By all appearances she is a pleasant and kindly person who enjoys her job as a teacher at an English junior school. She has an American boyfriend, Tom (Jesse Eisenberg), who is employed as a groundskeeper at the same school, and the two exhibit a warm, playful manner with each other that suggests a down-to-earth Millennial couple who haven’t quite settled into their middle-class rut yet. Much like April and Frank Wheeler in Richard Yates’ scathing indictment of 1950s America, Revolutionary Road, there’s also something a touch smug about Gemma and Tom, as though they imagine themselves to be smarter and more self-aware than their peers.

This sense of sardonic remove is evident when the couple visit the storefront for a peculiar real-estate development called Yonder. Gemma and Tom are, in fact, house hunting, but their interest in Yonder and its odd-duck salesman, Martin (Jonathan Aris), smacks of smirking irony. They acquiesce to a tour more out of amusement than good-faith curiosity, and Martin eagerly leads them on a prolonged road trip to the development site. Obviously Gemma and Tom would never actually choose to live in such a place: a treeless, prefab labyrinth of identical two-story houses all painted the same shade of celadon green. While the unnervingly plastic Martin enthuses about the features of model unit No. 9, they snicker over the oppressively anonymous, middlebrow décor. (The foyer features a painting of the house, and the master bedroom a painting of … the master bedroom.) Of course, there are more mysterious details, like the his-and-hers clothing laid out on the bed, and the apparent lack of any other residents in the entire subdivision.

When Gemma and Tom wander off on their own for a moment, Martin abruptly vanishes – along with his car – and so the perplexed couple return to their own vehicle and prepare to leave Yonder behind. Or at least they try to leave, quickly becoming lost in a maze of identical streets and identical homes, growing more irritable and frazzled with each turn that leads them back the way they came. After meandering through the development for hours on end, their car finally runs out of gas, stranding them directly in front of No. 9. By this point, the sun has long since set, and lacking any other options, the couple resign themselves to spending the night in the model home.

In the morning, however, their dilemma remains. They try to walk in a straight line in one direction, hopping fences as needed, but by nightfall they are again back at No. 9. The day after that, Gemma and Tom discover that a box of groceries and other supplies has been left at the curb, all of the products bearing uncannily generic labels. In desperation, Tom sets the house ablaze, and the pair fall asleep while watching in satisfaction from across the street as the structure burns to the ground. Naturally, they awaken the next day to find that No. 9 is still standing, pristine as ever. What’s more, a new box has been delivered, containing – to their shock and confusion – a naked infant boy. There is no explanation, only a single sentence printed on the lid: Raise the child and be released.

From this bizarre Twilight Zone conceit, director Finnegan (Without a Name) and screenwriter Garret Shanley – who share a story credit – craft an upsetting and unpredictable tale of captivity. It’s easy to describe Vivarium as an allegory about the lifeless aesthetic and cultural homogeneity of suburban existence, as well as the societal pressure to adopt said lifestyle and become a “normal” adult. To be sure, Finnegan’s feature is satirizing suburbia, if unsubtly. The film transforms the bland comforts of middle-class life into a literal prison of forlorn futility, one where the perfectly puffy little clouds seem pasted into the firmament and no breeze ever wafts through the eerily deserted streets. This is nothing new, of course. As Yates’ 1961 novel illustrates, artists have been dismantling the ennui of postwar bougie life almost from its beginning, although such cultural criticism is not limited to fraught family dramas. Genre films such as The Stepford Wives (1975), Edward Scissorhands (1990), and Pleasantville (1998) have memorably employed outlandish concepts to skewer the Western world’s vast wasteland of two-car garages and landscaped cul-de-sacs.

Vivarium escalates its fantastical premise to truly nightmarish levels, but the underlying message – spoiler alert: suburbia is a soul-sucking purgatory of small-minded routine and cultural vacuity – is hardly original or insightful. Fortunately, Finnegan’s film has more on its mind than an uninspired savaging of middle-class conformity. The Boy (Senan Jennings) left on Gemma and Tom’s doorstep grows with unnatural speed, appearing roughly 7 years old after just three months in the limbo of Yonder. His ceaseless, puerile demands – and his piercing screams when he doesn’t immediately get his way – rapidly grind both adults down into a permanent state of petulant exhaustion. Tom eventually finds a distraction, digging into the rubbery “soil” underneath the backyard lawn in the hopes that an escape (or an answer) lies somewhere below. Gradually, this excavation comes to consume his every waking hour, which means that Gemma is saddled with cooking, cleaning, and meeting the Boy’s endless needs. One can hardly blame her when she ultimately relents and allows the Boy to watch the only thing ever shown on their television: a weird shifting pattern of black-and-white blobs accompanied by a crackling, slithering soundtrack.

The ease with which even well-meaning, progressive-minded heterosexual couples can drift into traditional gender roles is a key theme in Finnegan’s film, as is the way that careerism, materialism, and even the physical environs of suburban living subtly contribute to this slippery slope. The previously fun-loving Tom grows increasingly distant and hostile as the never-ending, backbreaking toil of the backyard excavation wreaks havoc on his physical and mental health. Notwithstanding the Boy’s obvious inhumanity and off-putting weirdness, Tom’s antagonism toward the child – as well as his slow-motion abandonment of the household for the grueling comfort of his ever-growing hole – nudges Gemma closer to the Boy, her maternal instincts improbably stoked by what Tom calls the “little mutant.” Like Jennifer Kent’s The Babadook (2014), Vivarium stares into the abyss of maternity with discomfiting candor, acknowledging the wearying tug-of-war between a mother’s primal caregiving instincts and her revulsion at the selfish, shrieking little hobgoblin that shackles her.

At one point Gemma discovers what appears to be a cryptic instruction manual filled with unintelligible symbols and weird diagrams that suggest Being John Malkovich. (It’s one of several details in Vivarium that evoke Spike Jones’ defiantly unstable 1999 mindfuck.) Gemma never deciphers the book and it is never directly relevant to the plot, but this dead-end subplot capably stands in for the bewildering glut of advice that confronts new couples, parents, and homeowners – a cacophony of frightening dos and don’ts that dissolves into garbled nonsense. A broader, more existential horror can be discerned in the film’s distillation of family life into its absurdist, Sisyphean essence. Simultaneously recalling and inverting Hereditary (2018), Finnegan’s film imagines parenthood as a kind of vampiric thralldom, one whose ultimate result is the transmission of vitality from one generation to the next. The terror of Vivarium is not that everyone becomes their parents, but that everyone is replaced by their children, in an endless, hollow cycle of parasitism.

One can easily envision a more focused and less eccentric short-film version of Vivarium – or perhaps an episode of an anthology TV series – that tackles at least some of these themes in under 30 minutes. Indeed, one of the primary weaknesses of Finnegan’s feature is the escalating, almost arbitrary weirdness of its plot, which drifts from one repulsive, outlandish development to the next. It feels more like the fever-dream indulgence of surrealist horror rather than the narrative parsimony of allegory, inidicating the extent to which the latter ultimately feels secondary to the former. There’s nothing wrong with surrealist horror, of course, particularly when it’s presented with so many queasy, disquieting touches, many of them related to the Boy’s strange demeanor and behavior. (Finnegan overdubs Jennings’ dialogue with a slightly distorted adult vocal performance, and the effect is horribly unsettling, especially when the Boy mockingly mimics Gemma and Tom.)

However, Vivarium is so obviously about something that its absorption with creepy, sci-fi world-building – which concludes with a Möbius loop so bleak it would make the Coen Brothers recoil – undercuts its more acerbic ambitions. Unlike Dogtooth (2009), which similarly concerns itself with a twisted nuclear household, the film’s fantastical elements are too precise to permit a more open-ended metaphorical richness. Finnegan's film is full of choices, as they say, but those choices don’t truly resolve into the coherent thesis one typically expects of a sci-fi/horror allegory. Paradoxically, this leaves Vivarium often feeling weird for weirdness’ sake, as though the film were eager to make viewers squirm in their seats over its redolent perversities without any regard for what those perversities connote. Fortunately, Finnegan’s feature still manages to leave a deep and thoroughly upsetting impression. The film ultimately succeeds on the strength of its cult-flick strangeness and unsettling thematic murmurs, rather than any specific caustic cultural critique.

Rating: B-

Vivarium will be available to rent from major online platforms on Mar. 27.