Bill Bryson is ambling around his New Hampshire home when he comes across an entrance to the Appalachian Trail, the world's longest hiking path. This sucker is long: it stretches over 2,100 miles from Georgia to Maine. Naturally, Bryson's instantly decides that he wants to hike the whole thing.
Unfortunately, the only hiking partner he can find is Stephen Katz, an old friend and recovering alcoholic. Bryson and Katz go way back: they took a trek across Europe together when they were fresh out of college… and drove each other insane. Without any other choice, however, Bryson meets up with the woefully out-of-shape Katz and hops on a midnight plane to Georgia.
So Bryson and Katz hit the trail. Although Bryson enjoys the grueling hike, Katz is less enthused to sweat it out every day. At least they're getting along, though. After several bone-breaking weeks, however, Bryson makes an awful realization: for all their effort, they've barely scratched the surface of the AT. It'll be impossible to hike this entire thing.
Surprisingly, this gives the two men a sorely needed boost. They spend the next several weeks hiking through Virginia before Katz heads home: he needs to work for a few months before meeting back up with Bryson. Bryson tries to hike on his own for a while, but he finds the experience unfulfilling.
Luckily, Katz meets back up with Bryson and our two bros happily hike the AT once again. After taking a stop in town, however, Bryson discovers that Katz has fallen off the wagon and is now drinking. This infuriates him. The two men eventually make up when they're back on the AT, with Katz revealing that he relapsed because he has an incredibly lonely life.
The next day, while traveling through a brutal section known as "The Hundred Mile Wilderness," Katz goes missing. Bryson freaks out, fearing the worst, and goes an entire day without seeing his friend. They finally come across each other the next day and Katz, horrified by his near-death experience, decides that they have to leave the trail. Although they never end up completing the entire AT, they decide that the important part is that they tried.