Set in Mexico on the Day of the Dead in 1938, the novel follows the last day in the life of Geoffrey Firmin, a British consul with a severe alcohol addiction. Through his interactions with his estranged wife and half-brother, the book explores themes of despair, betrayal, and the destructive power of addiction, against the backdrop of political and social unrest. The impending eruption of the nearby volcano serves as a metaphor for Firmin's deteriorating mental state and the looming world war.

The novel is set during the Mexican Revolution, focusing on a whisky priest who is on the run from the authorities who have outlawed Catholicism. The priest, who is flawed and sinful, travels across the country to evade capture, minister to the faithful, and find a way to repent for his sins. Despite his moral failings, the priest's compassion and commitment to his faith make him a symbol of hope and resilience in the face of oppression. The book explores themes of faith, redemption, and the human struggle with sin.

The book follows the journey of a young woman who crosses the Mexico-US border to find her brother. Along the way, she encounters various characters and obstacles that challenge her identity, her understanding of her culture, and her perception of the world. The narrative is filled with allegories and metaphors that provide a deep exploration of migration, language, and identity.