There’s an interaction in the middle of Chilean filmmaker Sebastian Lelio’s “A Fantastic Woman” that perfectly describes the film’s conflict and asserts its core thesis. Two women meet in a downtown Santiago parking garage to exchange the car of the recently deceased Orlando (Francisco Reyes). It’s the first meeting of his girlfriend, Marina (Daniela Vega) and his ex-wife, Sonia (Aline Kuppenheim), and Sonia is anxious to get her eyes on Marina. “Just flesh and bones,” is how Marina describes herself to Sonia — she’s just another human body, like everyone else. But to Sonia, Marina is something else, a “chimera,” a mythical fire-breathing monster, part lion, part goat, part serpent.

There is something mystical and magical about Marina. Her unwavering gaze, powerful presence, intoxicating singing voice and her ability to see and interact with the dead — it’s all otherworldly. But Sonia’s intended assessment is much baser; she’s referring to Marina’s gender. She is a trans woman, and when Sonia refers to her as the “chimera,” an interspecies monster, it’s a cruel denial of her humanity, her “flesh and bones,” her existence. In “A Fantastic Woman,” Lelio explores the aggressions and oppression that Marina endures when something as profoundly human as death occurs.

Older businessman Orlando and Marina, a nightclub singer and waitress, are deeply in love, in the throes of a relationship that’s exciting, comfortable and sexy. They’re planning for a future: trips, moving in together, the culmination of a yearlong “soap opera,” as described by Sonia. When Orlando wakes up in the middle of the night dazed, with labored breathing, Marina rushes him to the hospital, where he suddenly dies, and her entire world gets pulled out from under her — the apartment, the dog, the car, her love.

Despite it all, Marina fights, because she must. Vega turns in a stunning, fierce and vulnerable performance, casting spells with her eyes. Lelio makes her the focus, and again and again her eyes break the fourth wall, whether riding an elevator, readying herself in a mirror or performing a fantasy dance number through the depths of her pain. Each time it’s a confrontation with the audience, an assertion of her soul. Marina is fighting simply to exist, and the film celebrates that existence.

“A Fantastic Woman” wouldn’t be the same without Vega — she makes the film what it is, shapes it with her body and spirit. As Marina she is heartbreaking, hopeful and undeterred, marching through her grief and trauma, leaning into the wind that tries to blow her down. She is powerful and delicate simultaneously, in equal measure.

Lelio crafts a world that’s realistically, distressingly unfair, violent and dark. But with Vega in the lead, her arresting screen charisma lends itself to some truly lovely and wonderful bits of fire and magic, proving to be quite the fantastic woman indeed.

MOVIE REVIEW

“A Fantastic Woman”

Grade: A

Starring Daniela Vega, Francisco Reyes, Luis Gnecco and Aline Kuppenheim. Directed by Sebastian Lelio.

Rated R for language, sexual content, nudity and a disturbing assault. Check listings for theaters. 1 hour, 44 minutes.

Bottom line: Powerful film about an unfair world