Longshoreman Johnny Barnes (Burgess Meredith) is in love with Kitty Tracy (Irene Hervey), barmaid at her father's waterfront saloon, and he beats up Cassidy (Joe Downing), a crooked politician who has been annoying her. Cassidy is murdered that night and Johnny is jailed for the crime. Kitty, her father Andy Tracy (Raymond Walburn), and waterfront-priest Father Cameron (Robert Armstrong believe Johnny is innocent but all evidence points to his guilt. Johnny's story that he was at pier seven watching a tugboat being repaired is discredited by the police, who prove that pier seven has long been closed, and no tugboat such as the one described by Johnny can be found. Following up a clue found by her father, Kitty finds the boat and uncovers the identity of the real murderer, Alcatraz escapee Monte March (Edward Pawley). Kitty and Father Cameron locate and confront him, but his loving wife Frances March (Esther Ralston) is ready to defend him. A terrific struggle between Kitty and Frances, and the priest and the murderer will decide theirs, and Johnny's end.