In the Brazilian countryside, poor sharecroppers join a messianic group led by Joaquim, who believes he is the reincarnation of Jesus Christ. Gaining power over the peasants, he begins to persecute those who do not pay absolute obeisance.

Chief of Police Rui, a happily married man of principles, is in charge of investigating Joana, a teacher who's accused of political crimes. After some false starts, he manages to arrest her, but is startled to learn that she's also a nun. The revelation doesn't alter the natural course of events: he must torture her in order to obtain a confession, and gets increasingly attracted to her.