The novel is a poignant exploration of the human condition, set against the backdrop of a tuberculosis sanatorium in the mountains of pre-World War II Spain. It delves into the lives of the patients and staff within the sanatorium, weaving a complex tapestry of love, betrayal, and philosophical introspection. The narrative focuses on the intense and tragic love affair between a disenchanted monk and a passionate, free-spirited woman, both seeking meaning and redemption amidst the despair of their illness. Through their story, the novel examines themes of morality, existential anguish, and the struggle for spiritual and emotional liberation.

The book is a harrowing narrative of a man from rural Spain, chronicling his life marked by violence and hardship in the early 20th century. Written as a series of letters from prison, the protagonist recounts his tumultuous journey through a series of misfortunes, familial strife, and brutal personal impulses that lead him down a path of murder and eventual execution. The novel delves into themes of fate, existential despair, and the brutal realism of peasant life, offering a stark portrayal of a man struggling against the inexorable pull of his own tragic nature.