Mia Wasikowska plays Robyn Davidson, who hiked across the Australian desert, and Adam Driver is National Geographic photographer Rick Smolan, in “Tracks.” (Matt Nettheim/The Weinstein Company via Associated Press )

In 1975, Robyn Davidson came up with a plan that was almost universally ridiculed. The 20-something Australian decided she would walk across the Australian desert. The 1,700-mile trek from Alice Springs to the Indian Ocean would take six months and, with the exception of four camels and her dog, Davidson would go it alone.

Davidson wrote about the experience in her memoir, “Tracks.” It’s not exactly a movie-ready story, given that it’s about a mildly misanthropic woman marching for miles, day after day, under the scorching sun. She doesn’t do a lot of talking, and no zombies appear to liven things up. But for all its simplicity, “Tracks” the movie is a poignant, deeply emotional story.

Casting was key for the role of Davidson, who spends so much time alone on screen, and Mia Wasikowska is a perfect fit. She’s well-suited to playing outsiders, whether it’s Alice in Wonderland or Jane Eyre, because her sweet, sad eyes make her so utterly sympathetic. She’s also a great physical match for Davidson, who was photographed by National Geographic’s Rick Smolan during her trip. Those photos appear during the closing credits and convey how detail-oriented the filmmakers were.

Adam Driver plays Smolan as Davidson’s foil. Where she’s quiet and enigmatic, he’s aggressively chatty and openhearted. He’s a nice guy, but Smolan inevitably annoys Davidson, asking her to pose in all sorts of ways during his monthly drop-ins. Previews and posters for the movie make it seem as if a romance between the two is a central theme, but that isn’t the case, even if they did have a fling.

If “Tracks” is a love story at all, it’s one between Davidson and the often unforgiving land, or perhaps between Davidson and her cherished dog. She explains that the only time she feels free is when she’s away from society, somewhere remote with her animals. We see how she arrived at this point through a mix of lovely, unobtrusive narration and affecting flashbacks.

There are some unnerving moments during Davidson’s trip, but the movie doesn’t milk any incident for more drama than it needs. And there’s power in its understated approach. When Davidson tries to refuse offers for a radio or gun — two things she ends up taking and needing — Smolan responds with a simple yet potent line: “Do you want to die out there?”

That question hangs over Davidson’s journey while the audience tries to decipher why a person would give away almost all of her possessions and march across the desert in sandals and a sarong. It all looks appropriately unglamorous, with Wasikowska wearing a layer of grime, her hair matted as she swats at ever-present flies. But the setting is spectacular. Director John Curran (“The Painted Veil”) captures the stark allure of the landscape so well, there are moments you might almost understand why Davidson chose to go there.

★ ★ ★ ½

PG-13. At area theaters. Contains language, disturbing images and partial nudity. 112 minutes.