Two decades ago, Chris McCandless, a young American adventurer and the talented offspring of prosperous middle-class parents, was discovered lifeless in an abandoned bus deep within the Alaskan wilderness. His story inspired the acclaimed book and film “Into the Wild.” Today, PBS revisits McCandless’ journey, attempting to unravel the reasons behind his decision to cut all connections with his past, dispose of his money, adopt a new identity, and venture into the Denali Wilderness. Newly released letters from McCandless, along with fresh and unexpected interviews, delve into the enigma that continues to captivate audiences and has cemented its place in American literature.