An engaged couple goes on a long trek, backpacking together through the Caucasus Mountains with only a guide for company. Alex (Gael García Bernal) is sexy and cool, Nica (Hani Furstenberg, an actress lucky enough to be a cross between Franka Potente and Jessica Chastain), even sexier and cooler. Very little happens except that we get to see how comfortable and happy they are together, exploring the mountains and valleys of Georgia. Then suddenly there’s an encounter with strangers during which their strengths and weaknesses are exposed. Blink and you’d miss it, but the power of this vital split second is astonishing. This meandering walkabout, based on a short story by Tom Bissell called “Expensive Trips Nowhere,” turns into an exploration of all the ambiguity that lies ahead of the pair. Will Alex and Nica make it out of the mountains intact as a couple? Director Julia Loktev keeps her cards close; it’s up to the viewer to mull it over and decide their future. The movie is a feature-length reading of a short story, but its slimness is deceptive; Raymond Carver would have loved it.