Simon James (Eisenberg) is a timid office clerk working in an ominous government organization. He is overlooked by his boss (Wallace Shawn) and colleagues, scorned by his mother, and ignored by Hannah (Wasikowska), the lovely copy room girl he pines for. Undermined and undervalued everywhere he turns, it seems that his directionless life couldn't get any worse-until the arrival of James Simon, his new co-worker. James is both Simon's exact physical double and his opposite-confident, charismatic and seductive with women. To Simon's horror, James slowly starts taking over his life.