The Treasure of the Sierra Madre tells the gripping story of three down-and-out adventurers in search of gold in the mountainous terrain of Mexico. The novel explores not only their physical trials but also delves into their psychological unraveling as greed and suspicion take hold. It paints a vivid portrait of how the allure of wealth can corrupt the human spirit.

Early Struggles and Alliances

The narrative begins with Dobbs, who is broke and jobless, desperately contemplating ways to scrape together some money. After managing to beg a peso, he rents a bed in a rundown hotel, treats himself to a meal, and buys a lottery ticket from a persistent beggar child. His attempts to find work lead him to the oil fields, but he fails to secure a job. Brief employment with a deceitful contractor follows, who refuses to pay his laborers. It is here that Dobbs meets Curtin, another American cheated by the same boss, and together they compel the contractor to pay them what they're owed.

The Lure of Gold

Not long after, Dobbs and Curtin come across an old prospector named Howard, who captivates them with tales of La Mina Agua Verde, a legendary source of Aztec treasure. Howard's stories, tracing back to the Spanish conquest, reveal how the quest for gold has historically led to exploitation and destruction. The mine, long lost after the Spaniards were massacred, was once rediscovered by a college student with an ancient map, who, along with Howard and others, was ultimately thwarted by greed. Despite the cautionary nature of these tales, Dobbs and Curtin are enticed by the promise of gold and persuade Howard to join them on an expedition to the Sierra Madre.

The Journey and Challenges

The trek is arduous, with Howard’s experience proving vital to their survival. Despite this, Dobbs frequently doubts Howard’s guidance. Setting up camp introduces them to extreme temperatures, dangerous wildlife, and painstaking labor. The discovery of gold does not bring relief; instead, it sows seeds of distrust among them. Howard warns Curtin that the onset of "gold fever" is inevitable, and tensions rise with increasing disputes. Howard's presence is the only thing preventing Dobbs and Curtin from coming to blows. He eventually persuades them to plan for a return within weeks, which temporarily eases tensions as they look forward to leaving with their newfound wealth.

Intruders and Warnings

As Curtin returns to camp one day, he is followed by another American prospector, Lacaud. His appearance is quickly shadowed by Mexican bandits, recognized by Lacaud as the culprits behind a recent brutal train robbery. The bandits nearly kill the prospectors, but are thwarted by the timely arrival of Mexican troops. Seeing no threat from Lacaud, whose focus is on his own elusive mine, the men allow him to stay while they prepare to leave. Before breaking camp, Howard shares another story about the destructive power of greed.

An Encounter with Fate

The return journey is approached with caution to avoid attracting thieves. One evening, their meal is interrupted by Indians seeking help for an injured child. Howard leaves with them and manages to nurse the child back to health. In gratitude, the Indians insist Howard stays with them, prompting Dobbs and Curtin to plan their next move to Durango without him, carrying Howard’s share of the gold with the intention of meeting him later.

Betrayal and Consequences

Howard's absence marks the beginning of Dobbs's descent into irrationality, and Curtin becomes aware of Dobbs's intentions to murder him and abscond with all the gold. Though Dobbs feigns innocence, he ultimately shoots Curtin. Alone and increasingly unstable, Dobbs meets his end at the hands of three bandits near Durango. Meanwhile, Howard, now revered as a healer among the Indians, reunites with a recovering Curtin. They learn of Dobbs's murder, and the bandits' ignorant disposal of the gold, mistaking it for sand. Howard and Curtin find solace in laughter, recognizing the irony of their fate and the futility of their greed-driven endeavors.