"DO YOU KNOW what the Turing test is?" Nathan (Oscar Isaac) asks Caleb (Domhnall Gleeson). Caleb's a young programmer who's just arrived, via helicopter, at Nathan's remote mountain fortress. After finding his way through Nathan's security systems, he's equal parts star-struck and bewildered—in addition to being Caleb's boss, Nathan is the brilliant, reclusive CEO of a company that might as well be the unholy merger of Google, Facebook, and Apple. But yes, yes, Caleb stammers, he knows what the Turing test is. It isn't long until he figures out why Nathan is asking: Here, beneath forbidding mountains and behind locked doors, Nathan's been working on a technological breakthrough. A robot. A robot that is—in all the ways that matter—equal or superior to humans. A robot named Ava.

Ava (Alicia Vikander) is smart, and curious, and—in how she moves, how she talks, and how she learns—the first of her kind. A flawless melding of flesh-and-blood ingénue and sculpted chrome and plastic, Ava's spent her entire existence behind unbreakable glass, under Nathan's tutelage and surveillance. She wants to know about the world outside. She wants to know about Caleb, and she wants to know what Caleb thinks of her. And while Nathan has plenty of questions too—Caleb was summoned, it turns out, to give Nathan a second opinion on how lifelike Ava is—it's one of the questions Ava asks Caleb that might be the most important. Ava asks it softly, nervously: "Are you attracted to me?"

From Ex Machina's relatively realistic opening moments—it subtly calls to mind both Walter Isaacson's Steve Jobs and David Fincher's The Social Network—things spiral to stranger, creepier places. It's not as if the themes explored in Ex Machina are new—from Asimov to Blade Runner, we've pondered them before—but they're handled here with a depth and intelligence that gives them jarring impact. And the longer one watches, the more Ex Machina reveals: Nathan's chill, bro-ish charm floats on top of something more intense and driven; when Ava barely tilts her head, or takes an uncannily poised step, she does so with the off-putting sense of something both human and inhuman; even Caleb, who starts out trying to brag about being "hot on high-level abstraction," unravels as he tries to figure out what happens when theory becomes reality. Ex Machina doesn't just carve out time for these moments, it is these moments; those wanting sci-fi spectacle or to gawp at a winking sexbot should probably look elsewhere.

Assembled with cool, careful steadiness by writer/director Alex Garland—who's directing here for the first time, after writing sci-fi stalwarts like 28 Days Later, Sunshine, and Dredd—Ex Machina gracefully twists between sci-fi and romance and mystery, unwrapping most of its concepts and thrills in dialogue, close-ups, and color. (Garland's story is largely confined to the sterile, over-designed interior of Nathan's mansion, but when color soaks the frame—during a trek to the forest, during an unexpected power outage, during an even more unexpected disco dance number—it does so with primal urgency.) Ex Machina works because of its details—the way Nathan pitches his voice between humor and threat, the way a crack in Ava's glass cage catches the light—even as it sticks in the mind because of its scope, both personal and technological. Like Ava, Ex Machina is remarkable not just because of its ideas, but also what it does with them.