Set in Post-World War II Los Angeles, a criminal shoots and kills a police officer in the middle of the night. Without any leads, the chief of the LAPD assigns Sgt. Chuck Jones and Sgt. Marty Brennan to investigate the murder and apprehend the culprits. When the dealer of electronics devices, Paul Reeves, is caught selling a stolen projector, the police identifies the criminal, and connects him to other unsolved robberies. Using the witnesses of his heists, they draw their face, but the true identity of the smart and intelligent criminal is not disclosed. The perseverance of Sgt. Marty Brennan in his investigation gives a clue where he might live.