Where the Sidewalk Ends tells the story of Detective Sergeant Mark Dixon (Dana Andrews) who is known for his rough and violent manner of dealing with criminals and suspects due to his conviction of being a law abiding citizen which his feather was not. Due to his behavior, his superior refuses to promote him and tells him that he is a good man but needs to exercise more control. The story becomes interesting when Dixon accidentally kills Ken Paine (Craig Stevens), suspected of murder and gambling, when Dixon hits him to protect himself. In order to save himself Dixon throws the body of Paine in a river. Later he is asked to investigate the murder of Paine. He attempts the blame the crime on Tommy Scalise (Gary Merrill) who is a well known criminal. At the same time he tries to protect the taxi driver Jiggs Taylor (Tom Tully) from getting blamed for the murder. Taylor is the father of Morgan Taylor (Gene Tierney), wife of Paine who is abused by Paine. The story takes interesting twists and turns as Dixon tries to save himself as well as win his love Morgan.