Tom Welles (Nicolas Cage) is a surveillance specialist – what used to be known as a “private eye” – but his version of the profession is hardly the stuff of which legends are made. He has a modest, home-based practice in Harrisburg, Pennsylvania, where he lives an existence remarkable only for its normalcy with wife Amy (Catherine Keener) and baby daughter, Cindy. Respected but still waiting for a big break that will improve his professional status, Welles spends most of his time on routine cases involving unfaithful spouses and the like. Nothing too dangerous, nor too threatening…until a small, innocuous-looking plastic reel of film turns Welles’ life upside down, sending him down a sordid and terrifying path into society’s darkest corners.