A complex novel of contrapuntal development, Lafcadio’s Adventures is divided into four interrelated parts. In the first book, André Gide introduces the reader to a scholarly—indeed pedantic—freethinker and would-be scientist. Anthime Armand-Dubois, crippled by rheumatoid arthritis, is physically grotesque yet intellectually vigorous. Because of his misshapen body, he retreats into abstruse scientific research. Unlike his pious Catholic wife, Veronica, Anthime is driven in his studies to demolish the religious superstructure that, in his judgment, obscures reason and promotes superstition. A Freemason, he plans to publish in scientific journals his minor, often cruel, experiments involving animal vivisection and abuse. Then suddenly, he experiences a religious conversion. After his young niece prays for the forgiveness of his sins, Anthime has a vision of the Virgin; coming to his senses, he appears to be healed from his pain, throws away his crutch, and swears devotion to the Church.

In book 2, Gide treats the sophisticated, somewhat smug novelist, Julius de Baraglioul, who has just received a troubling letter from his distinguished father, Juste-Agenor de Baraglioul. The dying gentleman wants Julius to report to him information concerning the actions and intentions of a young stranger, Lafcadio Wluiki. With some misgivings, Julius visits Lafcadio’s shabby lodgings, reads the youth’s enigmatic diary, then is startled by the arrival of Lafcadio himself. Shortly thereafter, the two men, of vastly different temperaments and stations in life, discover their link to each other: They are half brothers.

In book 3, Gide introduces Julius’ gentle and ingenuous brother-in-law Amedee Fleurissoire. Quite comfortable with the routines of his bourgeois life and his bland marriage to Arnica (Marguerite de Baraglioul’s younger sister) Amedee is startled into heroic enterprise after learning a terrible secret. Through the intervention of Father Salus and the Countess de Saint-Prix, Arnica passes on to her husband the information that Pope Leo XIII has been imprisoned and that a false Pope has taken His Holiness’ place.

In book 4, Amedee, flushed with religious enthusiasm, begins his absurd journey to discover for himself the truth. With great discomfort, he travels to Rome, then—convinced by Protos (an adventurer who earlier disguised himself as Father Salus) into believing that the plot is a true conspiracy—agrees to secure from his wealthy brother-in-law letters of credit to ransom or release the supposed captive.

Lafcadio, the young adventurer, who has just inherited an annual income of forty thousand francs from his father’s estate, happens upon Amedee in a train compartment. To Lafcadio, Amedee is a complete stranger who nevertheless inspires a sudden thought: Why not commit a perfect crime—a gratuitous act for which there is no logical explanation—by pushing this innocent man from the train? Cool and emotionless except for the exhilaration of having committed an unprovoked, motiveless crime, Lafcadio later reads an account, while in Naples, of a mysterious accident that occurred recently near Capua, of a “Crime, Suicide...or Accident?” according to the newspaper headline. While in Naples, he also meets his half brother Julius, and the two discuss the import of the event. For Julius, the theme of an unmotivated crime would be perfect for his new novel. For Lafcadio, the game of discussing the subject but not revealing his own role in it is dangerous but entertaining. The game becomes truly dangerous, however, when Protos, disguised now as a pedantic law professor named Defouqueblize, confronts Lafcadio with incriminating cuff links that connect him with the crime; Protos blackmails the youth into cooperation.

Fortunately for Lafcadio, Protos himself is vulnerable: He has murdered his mistress Carola Venitequa, and the police soon have him in custody and charged with Amedee’s murder as well. Now Lafcadio has a moral dilemma. Should he confess to his part in the crime, or should he follow the advice of Julius’ daughter Genevieve (who is in love with him), and allow Protos to pay a double penalty, since he is already doomed? The choice is life with dishonor but with the promise of love and redemption, or death. The reader must guess which one Lafcadio will choose.