Cosmo Jones, a correspondence-school detective from a small town, comes to the big city to offer his services to the police. He happens by where a gangster is killed by an opposing gang. Socialite Phyllis Blake is running around with gang member Tom and the opposing gang plan on kidnapping her. Cosmo is with Sergeant Flanagan when the attempt is made in front of a night club, where a bystander is seriously wounded in the gun-battle. Police Chief Murphy blames Flanagan for the shooting and demotes him. Cosmo, with the aid of a porter, Eustace and Flanagan's fiancée, Susan, tries to find the killer. Phyllis is finally kidnapped and Cosmo decides the act was committed by one of the two gangs. He has her father place an ad in the newspaper that contact has been made with the kidnappers. Each gang thinks the other is pulling a double cross, and one gang wipes out the other.
Frank Graham
as Cosmo Jones
Edgar Kennedy
as Police Chief Murphy
Gale Storm
as Susan Fleming
Richard Cromwell
as Sgt. Pat Flanagan
Mantan Moreland
as Eustace Smith
Gwen Kenyon
as Phyllis Blake
Herbert Rawlinson
as Mr. James J. Blake
Tris Coffin
as Jake Pelotti
Charles Jordan
as Biff Garr
Vince Barnett
as Henchman 'Gimp'
Emmett Vogan
as Police Commissioner Gould
Maxine Leslie
as Mrs. Jake Pelotti
