The Power and the Glory chronicles the plight of a Catholic priest who, for eight years, has continued to say Mass and administer the sacraments, even though Mexico's revolutionary government has outlawed these practices.

Knowing that he will be executed if he is caught, the priest moves from village to village carrying on the work of the Church. He is relentlessly pursued by a nameless young lieutenant of police, a revolutionary who believes that the new government can help mitigate poverty; the lieutenant despises the Church for ministering to spiritual needs while ignoring poverty. The priest, however, believes that faith in the Church's teachings provides hope for the poor and oppressed. Because he considers himself a sinner, the priest empathizes with others who are weak, and feels compelled to fulfill his priestly duties despite the threat of execution. But the lieutenant sets traps for the priest by killing hostages in the villages where the priest has held Mass and by luring him with liquor. The inevitable confrontation between these two men brings the novel to a dramatic climax.