In their post in the Peruvian Andes, Corporal Lituma and his assistant Tomás find themselves trapped. Constantly threatened by terrorist commands and a violent nature, they are tasked with uncovering the mysterious disappearance of three people. Everywhere they turn, they are met with distrust, and eerie stories reach their ears. If it weren't for Tomás's burning memory of his adventurous love story with Mercedes, which he recounts to Lituma night after night, the two would likely succumb to this hostile, superstitious mountain world. Despite the harsh climate and the disturbing fragments of truth they gradually uncover, they refuse to give up. What happened in the mountains has the proportions of an incomprehensible drama.