This is pretty good. The three significant actors are all subtle and excellent, the shots of the Bolivian high altitude desert are stunning and the view into a completely different world is fascinating. As for the pacing, it would be easy to say it's slow, but this is not a long film and when dealing with issues like these, it's not dramatic events that count, but the slow changes caused to the daily routine by weather and health.
An old couple farming llamas for wool among the Bolivian Andes are struggling to survive because of a prolonged drought. All their water must be fetched in buckets from a river miles away. The old man's health is failing and their grandson comes to stay, hoping to persuade them to return with him to the city. Like their children, many neighbours have given up the grim struggle and departed, but how can they bring themselves to leave the remote and beautiful wilderness which is all they have ever known?
It could have been better done by giving a fuller picture of their daily life, particularly the woman's tasks, to replace some of the many shots of llama herding. What do they eat? Where does it come from and how is it prepared? And so on. Also I found the ending improbable, given what had gone before and this was likely just a symbolic repetition of a message which had already been made very clear. Something more practical would have worked better for me.