The film is set against the backdrop of Mexico's Cristero War, which took place between 1926 and 1929, when the Mexican government banned Catholicism and persecuted its followers. Clergy are separated from their congregations and worship is forbidden. Elias, the central character of the film, follows his wife's wishes by seeking out a priest to perform the last rites on their unborn son, whom she fears will die due to a fall she sustained. Upon finding one, he manages to persuade the priest to return with him to the village to perform the last rites, despite putting the safety of the community at risk. The Federales follow the pair and kill every man, woman and child in the village. Elias's family are able to escape, although his wife dies while giving birth to their son. Captured, Elias realises he is responsible for the deaths of his entire community and begs the priest for forgiveness before his execution. The priests says he is unable to do so and curses Elias's bloodline. Elias escapes and becomes obsessed with the concept of atoning for his sin. He moves his remaining seven children to the desert where they begin to build a monument to God. As his children begin to die through illness and accident, Elias maintains that God has forsaken him and his religious beliefs turn from reverence to homicidal and take over his and his children’s lives.