If you get up to go to the bathroom at the wrong moment during “The Loneliest Planet,” you’ll miss everything.

The UW-Cinematheque is hosting the Madison premiere of the film at 7 p.m. Friday at 4070 Vilas Hall, 821 University Ave. The screening is free, but seating is limited and first-come, first-serve.

Much of Julia Loktev’s gorgeous and unsettling film is like a travelogue, with long scenes of the three characters trudging through the vibrant green hills of the Caucacus Mountains in the country of Georgia. It’s a vacation for an adventurous engaged couple, Alex (Gael Garcia Bernal) and Nica (Hani Furstenberg), and I’m guessing the title is a play on those “Lonely Planet” guidebooks. There isn’t much to do out in these remote hills except hike, but they pass the time playing teasing word games (he’s teaching her his native Spanish, verb by verb) and all the other things young couples do when they’re in love, and the enormity of the world seems to reside in the other person.

“Planet” requires a bit of patience from the viewer at first; there are a lot of hiking shots, and while undeniably beautiful (this is a movie that demands a theatrical viewing) it can get a little repetitive to see similar shots of the same figures, tiny as ants, moving across an emerald backdrop. (Loktev only uses music during those extreme long shots, quickly cutting it off when the camera narrows in on the couple).

There’s a third figure with the couple, a local guide named Dato (Bidzina Gujabidze). He’s a somewhat mysterious figure, trying to make jokes in English while the couple nods politely. There’s a few moments of uncertainty — at one point, Dato freezes in his tracks as if he hears something, but doesn’t say what. We sense something is going to happen to these three, but what?

And then, midway through the film, it finally does. It only lasts a few seconds, but has a profound impact, and we realize we needed all that time spent earlier with the happy couple to see just how profound. The rest of the film is, again, a lot of walking and some talking (although, tellingly, never about the incident). But everything’s changed. Alex and Nica are more distant, uncertain how to relate to each other. One of the fascinating aspects of “The Loneliest Planet” is how slight adjustments can completely alter the effect of what is basically the same shot, much as how a small moment can send love that seemed secure tumbling into doubt.

“The Loneliest Planet” is a film about connection, or the attempt at connection; everybody’s trying to learn each other’s language, both verbal and emotional, but there are limits to what you can understand about another person. It’s telling that, in some early scenes, the characters are visually obscured from us — in one local tevern, Alex and Nica sit in semi-darkness, illuminated occasionally by a rotating blue light from the dance floor. Out in the mountains, there’s nowhere to hide from the camera, and the couple learns that perhaps it’s best not to know exactly what’s in the other person’s heart, or their own.