An enigmatic doctor (Robert Forster) picks up a flighty middle-aged woman (Amanda Plummer) in the middle of the desert, seemingly on a whim. The two flirt awkwardly and feel each other out, a process frustrated by car troubles that put them at the mercy of oily con man David Thewlis. It's an intriguing premise and, for its first hour or so, American Perfekt unfolds slowly but deliberately, establishing a languid, unpredictable tone that's almost hypnotic. Well acted by all three leads, the first half hints at an intriguingly offhand approach that's refreshingly original. But as soon as Plummer and Thewlis' screen time makes way for Fairuza Balk, who shows up as Plummer's drifter sister, things go downhill fast, as American Perfekt turns into a crushingly ordinary, derivative tale of an eccentric serial killer on the highway with odd methods and a unique worldview. Eccentric serial killers have to be the most over-represented demographic group in the history of film and, sadly, American Perfekt's vision of pure evil is nothing that hasn't been presented countless times before. Worse, the film's swift transition from promising drama to punishingly mediocre thriller requires Forster to abandon the restraint that had characterized his performance and engage in hammy, over-the-top mugging. Forster, Plummer, and Thewlis all deserve better than this wasted opportunity, as does Balk, who acquits herself admirably in a role that requires her to do little more than scream, run around, and look scared.