Recently ordained as a priest, 24-year-old Father Amaro makes his way to Los Reyes, a quaint town in the fictional state of Aldama, to embark on his journey within the church. As a protégé of a ruthless political bishop, he quickly discovers the moral complexities surrounding him. Meanwhile, the local priest, Father Benito, is embroiled in a scandalous affair with a local restaurant owner while simultaneously overseeing the construction of an expansive hospital funded in part by a drug lord. On the other hand, Father Natalio (Damián Alcázar), the lone priest depicted positively, faces scrutiny for his support of leftist insurgents in his remote parish.
In this small community, Amélia (Ana Claudia Talancón), a 16-year-old girl, plays a critical role as a catechism teacher for the town's children. She is the daughter of Benito's mistress and finds herself at a crossroads, contemplating a future with Rubén (Andrés Montiel), a budding journalist. Their relationship is fraught with tension, as Rubén's non-belief clashes with Amélia’s staunch Catholic faith. Complicating matters further, Rubén's father is an outspoken anti-clerical atheist, leading to resentment within the town.
Amaro's attraction to Amélia quickly deepens, with their interactions becoming increasingly charged. During confession, she candidly explores the themes of love and sin, confessing to feelings she struggles to understand. Their dynamic intensifies when Amélia serves him at the restaurant, leading to a moment of innocent intimacy. However, as scandals surrounding Benito—such as his baptism of the drug lord's newborn—surface, Rubén is thrust into a moral quandary. Encouraged by his father's mountain of evidence, he exposes the truth about Benito's hospital, only to face repercussions from the Catholic establishment, which pressures the newspaper to dismiss him. Heartbroken, Amélia ends her relationship with Rubén, unleashing a torrent of insults, leading to vandalism at his family home and an explosive encounter between him and Amaro.
The film poignantly captures the conflict between desire and the vows of priesthood. Amaro grapples with guilt as he becomes entangled in an affair with Amélia, quoting verses from the "Song of Songs" to woo her. Their relationship spirals out of control when Amélia becomes pregnant. Amaro proposes they flee the town to shield his secrets, yet Amélia concocts a plan to convince everyone that Rubén is the father. In a desperate bid for legitimacy, she seeks Rubén, who ultimately declines her advances.
Tensions mount when Benito threatens to expose Amaro's actions, leading to a confrontation where Benito is injured in a fall. As the story unfolds, Amaro arranges for a backstreet abortion that tragically goes awry, causing Amélia to bleed profusely. In a frantic race to a city hospital, tragedy strikes, and Amélia dies before they reach safety, leaving Amaro in despair.
Though the local gossip spins a false narrative blaming Rubén for Amélia's predicament, a handful of townsfolk, including Benito and a cynical old woman, know the harrowing truth. The community chooses to uphold a facade, commending Amaro for his misguided heroism. The film culminates in a somber funeral for Amélia, attended by mourners who fail to see the devastating reality beneath their pious sentiments. In the end, Benito, now wheelchair-bound, turns away in disgust, a testament to the corruption and moral decay that permeates their world.
