After they break up, in spite of Montse's pregnancy, Santiago decides to spend his military service as far away from her as possible: in the Western Sahara, Spain's only African colony. There, he is one of the few Spanish soldiers to befriend the local Saharawi people, quickly falling in love with their customs and culture. But the year is 1975 and the colony will not last much longer. Following the death of General Franco and the Spanish withdrawal, Santiago becomes caught up in the brutal war between the Saharawi and invading Moroccan forces. He is entrusted with escorting a Saharawi friend's family on an epic journey, hundreds of miles across the desert.

Thirty years later, Montse, now a divorced doctor living in Barcelona, sees a photo of Santiago carried by a Saharawi patient. After discovering that he did not die in 1975 as she had been told and that he, like her, has lost both a child and a partner, she sets out to find him amongst the refugee camps of the Western Sahara, a journey that will prove to be every bit as dangerous as Santiago's so many years before.