Two flirting agents track down a killer, who is trying to get the money from the mail robbery.
The driver of a mail truck is killed, and the killer Crowley escapes to the west. Former partners Tom Mallory (Lee Tracy) and Doris Martin (Gloria Stuart) are told that Crowley's accomplices are in the hotel. They mail a letter to Jane Turner in Los Angeles, and Doris intercepts it. Tom arrests three men. Tom and Doris fly to Los Angeles, and Tom gets two dogs for a reward offered by Jane Turner. Crowley (Paul Guilfoyle) tells Eddie that he doesn't trust him or a woman. Tom waits at the post office. Jane Turner (Judith Blake) gets a letter with money, and Doris follows her to an apartment. Jane calls Norton to make up the shortage, and her husband Jerry Turner (John McGuire) tries to explain about the books. Doris rents an apartment, sees Jane go out, and bugs her apartment. Tom sends an unemployed man money from his son. Another woman asks for Jane Turner's mail and runs out. Tom follows her, jumps on her car, and arrests her and Eddie. At the post office Ruby (Irene Franklin) is caught promising marriage for money and agrees to marry a sheepherder.
Tom questions Eddie, but he won't talk. Three men get on the Jane's nerves while she waits. She tells Tom that she was in on it for Eddie. Tom writes a personal ad for poodles to send Crowley to the other Jane Turner's apartment. There Jane tells Jerry that she offered the $10,000 she found in the mail to Norton, while Doris listens by the bug. Tom calls on Doris, who serves him dinner. They dance as Jane and Jerry dance next door. Tom buys three poodles from the coded ad. Doris criticizes him for baiting a trap with her innocent neighbors. Tom is called that Eddie told them Crowley's address. Jerry is called that Norton committed suicide because of the shortages. Tom and his men enter a house by the window. Tom is shot at and shoots the man, who is not Crowley. Tom sees the ad and calls Doris to get the Turners into her apartment. Doris gets her gun and takes Jane's place. Crowley sneaks in and holds up Doris with a gun. Tom arrives and asks Jane where Doris is. Doris offers Crowley half and signals Tom, who comes in and arrests Crowley. In the final scene Tom asks Doris to marry; but she says he owes her $30. They fight and then kiss.
Combining sexual tension between the partners and clever detective work, Tom captures the criminals and a bride, showing that crime often does not pay, while those hired to catch them get regular salaries.