Gangster Duke Castenega (George Walsh) asks his ex-girlfriend, Kate (Marion Burns), to provide him with the combination numbers to safe deposit boxes at the bank where she works. When Duke is arrested, he escapes and hides in Kate's attic. Danny Dolan (Spencer Tracy), who's just received a promotion to detective, is assigned to find the gangster. He's in love with Kate's sister, Helen (Joan Bennett), and seeks her help in the investigation -- but Helen is reluctant to place Kate in jeopardy.