The show presents a popular plot device of an innocent man on the run from the police for a murder he did not commit while simultaneously pursuing the real killer. It had its antecedents in the Alfred Hitchcock movies "The 39 Steps", "Saboteur", and "North by Northwest." The theme of a doctor in hiding for committing a major crime had also been depicted by James Stewart as the mysterious “Buttons the Clown”, who never removed his makeup, in "The Greatest Show on Earth." Writer David Goodis claimed that the series was inspired by his 1946 novel "Dark Passage", about a man who escapes from prison after being wrongly convicted of killing his wife. Goodis' litigation over the issue continued for some time after his 1967 death.