“Day Night Day Night,” the verité-style chronicle of a young suicide bomber, resembles its title: stark, descriptive, but enigmatic. Taking place over two days and nights, Julia Loktev’s disciplined debut feature follows a teenager as she is prepared and sent out to detonate a backpack bomb in Times Square. The reserved, small-scale approach, which frustrates explanation or condemnation, yields a riveting work that, strange to say, extends the fragile possibility of hope.

The movie, which opens today at the IFC Center, is a handheld, point-of-view affair that stays physically close to the character but keeps us at arm’s length in other ways. We accompany the nameless girl as she meets her contact at a bus station, trains with masked handlers in a drab hotel room, and gets outfitted by bomb makers in an mysterious hideaway. But we are not privy to what led her down this terrible road to begin with. The identity and agenda (besides mass murder) of those shepherding her along, all unnervingly cordial, remains tantalizingly unspecified.

All we are left with is one girl’s face, and it tells a whole story at a glance. Luisa Williams, a nonprofessional in her first role as the bomber-to-be, is a slight teenager with sharply dramatic features: hollow eyes, finely carved bone structure, and pixie ears. From one scene to the next, her character can look pre-lit for intrigue or, more fitting to her years, exposed and overwhelmed.

Ms. Williams’s character, identified in the credits only as “she,” politely follows her handlers’ directions, yet at the hotel room calmly asks them to share her pizza with her. When they make her memorize the fake driver’s license they’ve provided, it has the ring of a grade school drill. Her voice always sounds surprisingly small.

Throughout the teenager’s journey, Ms. Loktev focuses shots on the bare facts of visual and especially aural detail, from clipping nails in the cramped hotel bathroom to the hazy, humid soundscape of the Times Square crowds. At street level, as she wanders, bomb trigger at the ready, realism becomes dizzying, feverish, amid the unreality of pending catastrophe. It’s worlds away from Hitchcock’s infamous ticking-bomb formula for movie suspense, back when suspense wasn’t a way of life.

Character becomes a stringently empirical matter; the viewer combs the text for clues. Is the whispered monologue of the scene’s opening shot, the girl’s head in inward-looking silhouette, a prayer or an inscrutably private steeling of nerves? (Does her scrupulous shaving and grooming on the eve of her mission refer to the well-known preparations of Islamist bombers?) And what about her parents, whom she appears to call at a pay phone?

Ms. Loktev’s treatment of psychology and politics may be oblique, but she is not making some muddle-headed bid for sympathy or the withholding of judgment. The events of the film’s purgatorial final third reveal a larger strategy of compassion and even a kind of optimism that are more convincing because they aren’t pinned on to a conventional drama. The precarious ending, too, is far more attuned to the current desperate moment than a typical good-and-evil treatise or the self-aggrandizing re-creations of “United 93.”

Beyond the immediate subject of terrorism, the exceptional circumstances in “Day Night Day Night” also have a way of bringing out the political currents in the ordinary world around the girl as she broaches the Times Square throngs. To our frayed senses, everything seems weighted with significance, like the unwanted attentions of a borderline hostile pick-up artist — an unwelcome part of daily street life whose aggression lights up clearly in the void of our anticipation. Ms. Loktev and company also introduce an element of street theater by having the young actress, amid unrehearsed crowds, effectively simulate the technique of an actual suicide bomber — small wonder that the performance artist Vito Acconci pops up in the credited acknowledgments.

Ms. Loktev, who has a background in sound design, has chosen two peculiarly well-suited technicians for the movie’s immersive style. Leslie Shatz, who did sound on Gus Van Sant’s experimental take on Columbine, “Elephant,” registers every crunch, rustle, and, in one memorable instance, clicking car turn-signal. Cinematographer Benoît Debie previously shot Gasper Noé’s “Irreversible,” another study in horrific forward momentum.

Like another recent release, “Zoo,” a documentary that featured “zoophiles,” “Day Night Day Night” is an aesthetically bold movie on a subject destined to alienate some portion of the audience. As a rigorously controlled experiment in form and perspective, the film does have a self-contained quality, as if it threatens to self-destruct after viewing. But in realizing the limits of overarching psychological and political explanations, Ms. Loktev is able to surprise us with a pointed and unexpected understanding of a more universal sort.

Through May 15 (323 Sixth Ave. at West 3rd Street, 212-924-7771).