Susan Hart, assistant to private detective Russ Ashton, is given a camera concealed in a hat box and assigned to take a picture of a woman. A gun is accidentally hidden in the box and the woman is killed. Susan is charged with murder, but Russ and his less-than-useful associate, Harvard, get on the case.

Chick Williams, a prohibition gangster, rejoins his mob soon after being released from prison. When a policeman is murdered during a robbery, he falls under suspicion. The gangster took Joan, a policeman's daughter, to the theater, sneaked out during the intermission to commit the crime, then used her to support his alibi. The detective squad employs its most sophisticated and barbaric techniques, including planting an undercover agent in the gang, to bring him to justice.

A deep-sea diver becomes romantically involved with the daughter of a gold smuggler.

A taxi dancer with a jealous husband finds herself falling for a wealthy client.

Richard Walters is condemned to death for a murder he claims not to have committed. He arrives on death row just before a brutal inmate leads the other convicts in a violent uprising. Walters gets caught up in the riot, while on the outside his friends are trying to find evidence of his innocence.

Wild Bill Saunders recruits a team of paroled convicts to subdue a lawless gang.

Moe discovers Curley's unknown boxing talent when he knocks out the Champ at a restaurant when Larry plays "Pop Goes the Weasal" on the violin. Moe becomes Curly's manager, and they win every fight, with the help of Larry. At the championship game, though, Larry's violin breaks. Curly is getting beat down bad when Larry makes his unexpected entrance and helps Curly prevail.