Bill Bryson, instead of retiring to enjoy his loving and beautiful wife and large and happy family, challenges himself to hike the Appalachian Trail: 2,200 miles of America's most unspoiled, spectacular, and rugged countryside from Georgia to Maine. The peace and tranquility he hopes to find, though, is anything but, when the only person he can find willing to join him on the trek is his long-lost former friend Katz, a down-on-his-luck serial philanderer....

A visitor from the future tells best friends Bill and Ted that one of their songs can save life as they know it and bring harmony to the universe.