Directors Justin Benson and Aaron Moorhead conduct a clever act of stylistic sleight of hand in their new thriller, “SYNCHRONIC.” Though narrative pieces are set into place in its early sections, the picture seems to meander, guided less by plot than a pervading feeling of things careering out of control—a palpable dread, bordering on nihilism. The filmmakers lull us into sharing this perspective; we’re there to see something new, and we’ll go where they take us. And then, dazzlingly, it snaps into focus, and the viewer suddenly understands why hazy anxiety was so necessary, and where they’re going next. It’s a neat trick.

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Steve (Anthony Mackie) and Dennis (Jamie Dornan) are New Orleans EMTs; longtime friends and partners, they speak in shorthand and have fallen into behavioral patterns that have become a self-fulfilling prophecy. Dennis is the responsible family man, though he’s increasingly feeling like he fails his family; Steve is the footloose single party guy, but he’s increasingly aware of the emptiness of his existence—especially when a routine trip to the doctor leads him to discover that he has, in his words, a “gigantic brain tumor.”

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Theirs is already a tenuous line of work, and Moorhead and Benson create a visceral, almost horror-movie feeling of terror as they walk into their crime scenes and try to figure out what’s what. A string of particularly grisly accidents and overdoses keep pointing back to Synchronic, a synthetic drug that creates incredibly vivid hallucinations. Steve, who fancies himself an “amateur physicist,” tracks down several doses, and, figuring he has nothing to lose, decides to do some experiments.

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And that, frankly, is where I should stop. What he discovers, and how we discover it alongside him, is snazzy and snappy and clever as hell, and once those experiments and the various related plot threads converge, all the filmmakers have to do is tug them all together. Like their earlier genre picture “The Endless” (and its clearest influence, “Primer”), “SYNCHRONIC” can best be described as egghead indie sci-fi, in which the ideas are as exciting as the effects.

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What’s most striking about the filmmakers this time around is their tremendous sense of cinematic confidence. They never question if their audience is going to follow them along this strange, curlicued path; we’re dying to see where they’re going, and they goose things along with strategic deployment of Jimmy LaValle’s (aka ambient indie artist The Album Leaf) pulsing, coiling score, and the script’s little bursts of humor, loaded like landmines. The performances are all rich and lived-in (even Dornan is good), but Mackie really is the star of the movie, and shines in it. Those Marvel movies pay the rent, sure, but it feels like we’re losing out on some terrific performances while he’s twiddling his thumbs on green-screen stages in Atlanta.

Moorehead and Benson’s striking visual sense is on display primarily in the film’s vivid, pulsing hallucination sequences, horrifying scenes that feel real — because they might be? As with “The Endless,” the effects are jaw-dropping on their own merits —but even more so when we consider their limited budgets. You see every penny onscreen, in the nightmare-fuel drug-trip imagery, in the razor-sharp compositions and jagged cutting patterns, in the eerie, floating camerawork. They pull out all the stops (Dutch angles, backward motion, upside-down flips, gonzo POVs, long takes), and yes, at times, they’re showing off. But they’re also using this trickery to create a mood— to push a feeling, necessary to the narrative, that anything is possible.

The picture falls apart a bit in the home stretch. I’m not sure it earns its ending, or, more accurately, that it’s the right ending for this kind of material. But that’s a minor complaint; “SYNCHRONIC” is the kind of brainy, absorbing, all-out thrilling cinema that’s in dangerously short supply these days. [A]

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