Jeff Rydell has lulled himself into believing he is content watching Linklater films on a loop while working in what might be the last video store in America. His pleasantly pedestrian existence is shattered when he stumbles upon a bag stuffed with half a million dollars and the wallet of Ben Flanagan, a man who looks exactly like him. Flush with cash and a false identity, Jeff uses his knowledge of film to pretend to be a Hollywood producer kicking around Park City during the Sundance Film Festival. The new persona launches him into a whirlwind relationship with Cleo, a wannabe actress with a penchant for foreign accents and secrets of her own. But when the real Ben, a drug dealer looking to escape his own troubled past, discovers his identity has been hijacked, he hatches a plan for Jeff to take the fall for his crimes. Someone Else follows the misadventures of an in over their heads couple as they race through Utah subcultures not found anywhere in sanctimonious state tourism pamphlets, all while navigating devious doppelgängers, backsliding Mormons, extreme tattoo artists, and hired thugs.