Tina’s upper lip quivers as she sniffs the air. She’s in uniform, watching as passengers stroll through an airport terminal corridor. She’ll pull one off to the side and find hidden booze, drugs, even secrets. Tina has a talent; she can smell emotions like guilt and fear and shame. As border security guards go, she’s in a class all her own.

“Border” is based on a short story by ‘Let the Right One’ In author John Ajvide Lindqvist. That provenance tells you something about the film without spoiling any of its secrets or revelations. This is a compassionate and surprisingly sensual film about an outsider discovering and actively defending her identity.

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Tina is unlike anyone else. She describes herself as an “ugly strange human with a chromosome flaw.” She has a closer relationship to nature than most people; you can tell that even before she shares a peaceful midnight moment with a moose or a fox.

Eva Melander plays Tina as a wary outsider. She wears extraordinary makeup that creates a ragged mouth and Neanderthal brow to complement the character’s ambling, apish movements. (OK, she also looks a bit like the Geico cavemen.) But when the bear-like Vore (Eero Milonoff) strolls past Tina at work, she’s taken aback, possibly for the first time. He looks just like her. How can she be a genetic offshoot when Vore is so clearly cut from the same cloth?

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The movie paves two narrative paths. Tina and Vore circle one another, slowly revealing secrets and truths, even as an encounter with a suspect at work leads Tina to cooperate with authorities to investigate a heinous crime. Both stories proceed slowly, and the dance between the two characters is more compelling than the procedural. The resolution of one threatens to undermine the other, but “Border” ultimately keeps its footing.

Melander’s performance is remarkable. Director and co-writer Ali Abbasi brilliantly conjures an unlikely eroticism as Vore literally sniffs out Tina’s desire, and she begins to realize just how limited her understanding of her own identity has always been. This might be a satisfying experience even if Tina’s evolution was primarily existential.

But “Border” is an unabashedly physical movie. Long before Tina and Vore get it on — in a coupling that is unsurprisingly animalistic but still impressively tender — their scenes are charged with a frank sensuality. It’s almost confrontational because neither looks like characters typically subjected to voyeuristic observation on film.

There’s no polite way to say that Tina is ugly. And yet the raw emotion expressed in these scenes, and the way it consumes Tina is compelling. Melander so effectively communicates the character’s sense of discovery and joy, that this movie provokes questions about what we find attractive, and what the rigid structure of those rules does to anyone who falls outside their parameters.

“Border” is also effective as it portrays Tina’s quest for a personal identity. Her joy at finding a potential companion, whose existence she never even fantasized, is balanced by the difficult realities of coming to terms with who that person is. Just because they’re “the same” doesn’t automatically lead to compatibility. Discovering your life, at long last, doesn’t mean that living it gets any easier.

Check out all our coverage from the 2018 New York Film Festival here.