On a sweltering summer day in the sleepy town of Mercer, Montana, a comically hellish odyssey begins for easygoing gas station attendant Clay Bidwell (Joaquin Phoenix). His best friend, Earl, abruptly confronts Clay, having learned that Clay has been having an affair with Earl’s hot-to-trot wife, Amanda (Georgina Cates). With a horrified Clay looking on, Earl successfully engineers his own demise and frames Clay for the “murder.” Clay manages to cover up the mess and remain in the clear. The incident doesn’t do Clay and Amanda’s relationship much good, and she begins playing mind games with Clay. To forget Amanda, Clay goes on a hot date. To forget the ugly business with Earl, Clay goes fishing with his new friend, swaggering cowboy Lester Long (Vince Vaughn), who “never forgets a friend.”

That’s when Clay goes from the frying pan into the fire. The fishing jaunt is spoiled. The date ends dreadfully. Clay soon has the unwanted attention of laser-sharp FBI Agent Dale Shelby (Janeane Garofalo), who believes he may be responsible for a number of murders in the region. “Promise you’ll stop finding dead people,” pleads concerned Sheriff Mooney (Scott Wilson). Try though he might, every move he makes only puts Clay in deeper and deeper…