Confederate super-spy Johnny and his partner in crime Steve travel to San Francisco near the end of the Civil War, masquerading, respectively, as a singer/guitar instructor and a magic-elixir vendor. Once there, Johnny dons a fake wig, beard and mustache, and steals Union gold to bring back to the South, aided by a guitar that doubles as a gun.

Two actors who play detectives on the radio find themselves investigating a real crime masterminded by an arch-criminal named the Cobra.

A gang of criminals, which includes a piano player and an imposing former convict known as 'Gruesome', has found out about a scientist's secret formula for a gas that temporarily paralyzes anyone who breathes it. When Gruesome accidentally inhales some of the gas and passes out, the police think he is dead and take him to the morgue, where he later revives and escapes. This puzzling incident attracts the interest of Dick Tracy, and when the criminals later use the gas to rob a bank, Tracy realizes that he must devote his entire attention to stopping them.

A police detective uses his girlfriend to track down a homicidal maniac.