Two men running a carnival airplane ride are hired to fly to retrieve what they think are photos for a reporter. Actually, they are retrieving diamonds stolen from a noted gem dealer. As it turns out, their plane crashes on the very estate of the dealer. Thinking the duo are police officers, the dealer offers his home for their convalescence from the accident. Meanwhile, the diamonds have been snatched by a kleptomaniac dog and buried on the estate. When the smugglers track down the pair, they try to convince the dealer that they are officials from an institution from which the two have escaped. Before long, the carnival fellows, the crooks, the gem dealer and his family, along with a platoon of cops, are tearing up the grounds to find where the dog has buried the diamonds.

To investigate a gold-shipping scam, a postal inspector goes undercover and tries to infiltrate the gang he believes is responsible.

While breaking into a bank safe, a gangster overhears a bank employee singing and decides to put her in a Broadway revue

Protecting himself in an attack by rustlers, Rancher Steve Holden believes he has killed one of the attackers, young Bud Mathews, who in reality has warned Holden of the rustlers' approach. Unaware that Mathews was actually killed by rustler boss Cass Barton, Holden heads out to Mathews' home town where he plans to tell the boy's family of his death but instead uncovers a plan by a local businessman to force Mathews' father out of his ranch.

Joe Lane, radio entertainer and songwriter, learns that the manager of the studio, Arthur Phillips, has made improper advances to his wife, Katherine. Infuriated, Lane engages him in a fight, and the encounter results in Phillips' accidental death. Joe goes to prison for a few years, and when he is released he visits his son, Little Pal, at school and is begged by him to run away together.

In the 1810s, an old maid poses as her own niece in order to teach her onetime beau a lesson.

Rubber-legged comedian Leon Errol made his talkie starring bow in Paramount's Only Saps Work. Based on a play by Owen Davis Sr., the film casts Errol as James Wilson, a kleptomaniac who starts with picking pockets and ends up robbing a bank. Wilson's friend Lawrence Payne (Richard Arlen) inadvertently aids our hero during one of his heists, ending up in deep doo-doo with the law. Before Wilson is able to extricate Payne from his dilemma for the sake of heroine Barbara Tanner (Mary Brian), he pauses long enough to pose as a private eye -- and even gives bellboy Oscar (Stu Erwin) tips on how to spot a crook! If only all of Leon Errol's feature films had been as consistently hilarious as Only Saps Work.

Casey and Babe are sisters who work in a department store and each year the store puts on a show. As expected, things are going wrong with every act until Casey comes out to help Babe with her song. They are a hit, but in the final act, Casey again comes out and this time the president sees her act and fires both her and Babe on the spot. Benny is able to book Casey, Babe and Dean into Vaudeville and their act is popular. But before they have their shot at stardom, Dean and Babe leave Casey and the act.