Intent on seeing the Cahulawassee River before it's turned into one huge lake, outdoor fanatic Lewis Medlock takes his friends on a river-rafting trip they'll never forget into the dangerous American back-country.

Three friends, whose lives have been drifting apart, reunite for the funeral of a fourth childhood friend. When looking through their childhood belongings, they discover a trunk which contained details on a quest their friend was attempting. It revealed that he was hot on the trail of the $200,000 that went missing with airplane hijacker D.B. Cooper in 1971. They decide to continue his journey, but do not understand the dangers they will soon encounter.

Tim and Lee are married with a young child. The chance to stay at a fancy home in the Hollywood Hills is complicated by Tim's discovery of a bone and a rusty old gun in the yard. Tim is excited by the idea of a mystery, but Lee doesn't want him to dig any further, preferring that he focus on the family taxes, which he promised to do weeks ago. This disagreement sends them on separate and unexpected adventures over the course of a weekend, as Tim and his friends seek clues to the mystery while Lee searches for answers to the bigger questions of marriage and parenthood.