Into the Wild contains two interconnected plots, one that involves directly represented action and another that involves the careful development of a psychological portrait of Christopher McCandless. The first plot tracks McCandless’s journey into the wild, while the second tracks the development of Krakauer’s, and, implicitly, the reader’s, understanding of McCandless’s character and motivations. Neither plot is presented in linear fashion, and the two often intersect through the presentation of subtle detail, description, and the elaboration of multiple possible lines of cause and effect. Krakauer serves as the narrator throughout the book.

Into the Wild begins with the discovery of Christopher McCandless’s body by a group of Alaskan hunters who visit Denali National Park and Preserve on a yearly excursion. They radio for help. The FBI arrives and removes the body. Krakauer then visits with Wayne Westerberg, who knew Christopher McCandless as “Alex McCandless” and who provides an initial character sketch of the young man, Krakauer in a bar in Carthage, Wisconsin. Westerberg employed McCandless on and off on his grain elevator and remembers him as engaging, intelligent, and determined. Details from McCandless’s comfortable, middle-class Virginia upbringing and his dislike of materialism further Krakauer’s understanding of the young man. These same details take the narrator back to the first leg of McCandless’s journey west in his used yellow Datsun.

Just after graduating from college, McCandless drives to Lake Mead in Nevada, where a flashflood wets the engine of the Datsun. He leaves it and a number of other possessions behind. After two months of tramping, he buys a canoe on impulse and paddles down the Colorado River to Mexico. The journey takes five months. In the meantime, the McCandless family begins investigating their son’s disappearance. After his canoeing excursion, McCandless lives and works in Bullhead City, Arizona. An old man named Charlie takes him in briefly, before McCandless departs and meets Jan Buress and her old boyfriend in California. He engages in the social life of Buress’s drifters’ camp but leaves hastily, intending to embark on his trip to Alaska. Krakauer receives a letter from and then meets Ronald Franz, who describes to Krakauer the father-son relationship he established with McCandless. The narrator uses Franz’s story to initiate a line of investigation into the harm McCandless’s risk-taking behavior caused others.

Krakauer next visits Wayne Westerberg again and reconstructs McCandless’s last month in Carthage, South Dakota by speaking with Westerberg’s girlfriend and his mother. He acquires insight into McCandless’s troubled relationship with his father and relates that in late April, 1992, McCandless sent his friends postcards revealing that he was leaving for the wild, perhaps never to return. Krakauer’s investigation then move through his revelation that many readers of his original Outdoor magazine article about McCandless thought that Christopher McCandless was an incompetent, romantic fool. In response, Krakauer embarks on the telling of the stories of three other twentieth century wilderness fanatics who disappeared or died in the wild. He evaluates each and decides that McCandless has the most in common the young artist Everett Ruess.

Back at the bus in Alaska, state troopers attempt to identify McCandless’s body. Jim Gallien reads about the finding of the corpse and then contacts the police, setting off a string of events that lead to the identification of the body. Krakauer next visits with McCandless’s family, beginning with his father, Walt McCandless, and his mother, Billie McCandless. Billie shows Krakauer photographs of Christopher’s childhood and Walt describes the heartbreak his son has caused the family. Krakauer’s investigation then picks up a new subject: McCandless’s frustration with his family. When McCandless graduated from high school, he went on a trip to California and discovered that his father had been a bigamist. Krakauer theorizes that McCandless’s anger at this long-kept family secret offers some motivation for his desire to leave his life behind.

Krakauer then dedicates two chapters to his own ascent of the Devils Thumb. These parallel the plot of McCandless’s journey. Krakauer attempts the glacier’s north face and is rebuffed, then spends three days trapped at his base camp. After accidentally setting his tent on fire, he makes a desperate attempt at the southeast face and succeeds. Recalling this story allows Krakauer conclude that Christopher McCandless must not have been suicidal when he began his trip.

Jon Krakauer’s own trip to Denali National Park and the abandoned bus where McCandless died closes out the narrative. Along with three experienced Alaskans, Krakauer crosses the same river whose flooding prevented McCandless from leaving the wild. The four hikers encounter the bus in the late evening and examine its contents. Everything seems to have been as McCandless left it. The party eats dinner and reflects on the circumstances that could have led McCandless to head into the wild. In an epilogue, the author visits the bus again with Walt and Billie McCandless, Christopher McCandless’s mother and father.