French financier Paul Reynard (Rathbone) is sentenced to a ten-year term in a South American penal colony for bank fraud. His wife Irene (Gurie) and Paul's faithful servant Dirk (McLaglen) travel to Rio de Janeiro to arrange for Paul's escape. But once she's landed in the Brazilian capital, Irene falls in love with American engineer Bill Gregory (Cummings). After his escape Paul realizes that he's lost his wife forever to a better man. Seeking revenge, he prepares to shoot Bill in cold blood, but Dirk intervenes and kills Reynard instead.
Convicted on circumstantial evidence, Tommy Shay (Paul Fix), a young product of the Front Street slums, is sentenced to die for the murder of police lieutenant Carson (Monte Montague). When Denver Collins (Marc Lawrence), Tommy's only alibi, mysteriously disappears, Tommy's younger brother Danny (James McCallion) and his gang of alley kids (The Little Tough Guys) determine to find a way to save Tommy from the electric chair. Lieutenant Lewis (Harry Carrey), Tommy's arresting officer, also believes that the boy is innocent and tries to get the case reopened. For his efforts, Lewis is demoted to patrolman, prompting his son Bob (Frankie Thomas), a radio bug with an ambition to become a detective, to initiate his own investigation by which he hopes to find the real murderer and reinstate his father.
After his new wife's family convinces her to leave him, attorney Dan Preston leaves his law practice and sets off to travel around the country as a vagabond. When he returns home he finds his house rented by a novelist, Shirley Haddon. He adopts a mongrel dog, Picardy Max, and sets out to avenge himself against his ex-wife's family by entering Max into dog shows to compete against their pedigreed animals. Preston also begins a romantic relationship with Haddon.
A disgraced lawyer ends up working for a gang of share-pushers. He becomes outraged when he discovers that they are scamming his son's prospective father-in-law and eventually unmasks the villains with the help of the police.