"Ex Machina" is an unsuspectingly bold achievement of the science-fiction realm, minimalistic in setting yet massive in creative ambition. The sensational directorial debut of screenwriter Alex Garland (2010's "Never Let Me Go"), the film works on too many levels to count: as a thinking-person's fable; an imagination-rich cautionary tale; a contemporary "Frankenstein" for adult audiences; an intensely compelling four-character chamber piece, and, most surprising of all, an unnerving thriller with an arthouse spirit and the potential accessibility of a stimulating mainstream entertainment. Assured and immersive, the story's evolving mysteries and suggestive (but still tastily open-ended) revelations weave a hypnotic spell difficult from which to break free—not that anyone would want to.

When 26-year-old computer programmer Caleb Smith (Domhnall Gleeson) wins a company-wide competition to spend a week at the high-tech home of its reclusive CEO, Nathan Bateman (Oscar Isaac), it is a once-in-a-lifetime opportunity he wouldn't dream of passing up. The circuitous living-quarters-cum-research-facility, located among a secluded stretch of mountains he is transported to by helicopter, is heavily protected, each room requiring a security badge and the proper clearances to enter. Nathan is a brilliant, hard-drinking, decidedly eccentric man who requires that Caleb sign a non-disclosure agreement before he reveals to him the top-secret project on which he has been working. Reluctant to give up access to his property and electronic devices, he is nevertheless curious enough that he cannot help but acquiesce.

Nathan's creation, it turns out, is a fully functioning A.I. named Ava (Alicia Vikander), a barrier-breaking technological wonder that he believes is the first machine in existence to have a human-like consciousness. Caleb's job is to interact with Ava and provide feedback on whether he believes Nathan's claims to be true, and it isn't long before this awestruck visitor is drawn to the synthetic being's gentle, alluring, inquisitive, unexpectedly sexual nature. When the compound experiences a brief power outage during one of their sessions together and Ava takes it as an opportunity to warn him that Nathan is not to be trusted, it sets off a chain reaction of paranoia and a power struggle over ethics that could change nothing less than the course of history.

"Ex Machina" rarely leaves the confines of Nathan's state-of-the-art residence, but its meticulously constructed, antiseptically kept corridor of rooms gives the film a hyper-modern, almost otherworldly atmosphere. Just as Caleb feels like a stranger to this place, very much a guest in someone else's cryptic lair, so does the viewer. Outstanding technical credits—Rob Hardy's enveloping, richly toned cinematography; Mark Digby's (2013's "Rush") claustrophobically serpentine production design, and Geoff Barrow and Ben Salisbury's music score of mesmeric dissonance—add to the off-center mood as Caleb is alternately blown away by Nathan's invention and increasingly protective of it when he suspects Ava is just one in a long line of disposable test subjects. Caleb is aware that Ava is a machine, but it appears to have thoughts, feelings, yearnings and natural curiosities that force him to reevaluate what it means to be alive, and human. What is less apparent is what these characters' actual motives are, with Caleb empathizing with Ava's hopeless, sheltered plight while becoming suspicious of Nathan's intentions. And then there is Nathan's obedient, frequently nude Asian servant, Kyoko (Sonoya Mizuno), whom he claims to keep around precisely because she doesn't know English and won't ask questions.

Domhnall Gleeson (2013's "About Time") is a terrific protagonist, keenly intelligent but with an identifiable everyman quality. His Caleb acts as the eyes and ears of the audience, who willingly follow him without question and mirror his emotions as he starts to deeply care for Ava and begins to plot a means of escape. Oscar Isaac (2013's "Inside Llewyn Davis") continues his revelatory climb as one of the most dynamic performers working today, able to bridge the gap between a leading man and a diverse character actor. Isaac plays Nathan very close to the vest—does he mean Caleb harm? Is he hiding more nefarious plans? Or is he simply a wealthy eccentric who happens to drink too much?—which only serves to deepen the menacing allure and fascination surrounding him. The performance many will be talking about after the fact, however, is Alicia Vikander's (2015's "Seventh Son") breakthrough turn as Ava. Vikander's A.I. is not entirely unlike the ones played by Haley Joel Osment and Jude Law in 2001's "A.I.: Artificial Intelligence," but her fluid body movements and subtly expressive facial expressions and speech ensure that Ava is a true original. That one is also never sure if Ava, like Nathan, can be trusted only adds to the complexity of what Vikander has achieved.

"One day, the AIs are going to look back on us the same way we look at fossils," Nathan tells Caleb, his words all the more disturbing because they may eventually, thousands or even as little as hundreds of years from now, prove to be believably, eerily prophetic. As technology advances at an astonishing rate, are scientists and robotics engineers setting into motion humanity's last gasp? "Ex Machina" acknowledges this possibility with a provocative, forward-thinking vision that writer-director Alex Garland is clearly thrilled to explore. As unspoken conflicts of mistrust and manipulation boil over, the third act culminates in a series of reveals and confrontations that are as blunt as cold steel and as piercing as a sharpened butcher's knife. There is one key concluding moment that takes place off-screen, needlessly causing more questions than answers, but this is a minor quibble that virtually loses itself in the shadow of so much done exceedingly right. "Ex Machina" is a singularly chilling cinematic stunner that coexists as a wild daydream and a prescient glimpse into the future.