Jeff arrives in town to see the Sheriff only to find him just killed. The culprit is Clay Wheeler. When Jeff becomes friendly with Letty, Clay sends his man Ortega to kill him. Jeff foils the attempt and gets him to confess that Clay was the killer. With only old-timers Lafe and Bill to help, Jeff heads after Clay and his gang.
When he swaps horses with the Tombstone Kid — a wrongly accused man on the run from the law — singing cowboy Tex Randall gets arrested by the local sheriff in a case of mistaken identity.
The fourth of 12 singing Westerns starring the "Silvery-Voiced Baritone," Fred Scott, Melody of the Plains begins peacefully enough with Scott, as cowboy Steve Condon, warbling Don Swander and June Hershey's "Albuquerque." The story quickly takes a rather grim turn when one of Steve's colleagues is shot and killed after selling out to a gang of rustlers. Mistakenly believing he fired the deadly shot, a dejected Steve, along with sidekick Fuzzy, goes to work for Bud's father, a rancher nearly forced into bankruptcy by a crooked land developer.
There is a range war between the ranchers led by Tilden and the outlaw gang of Link Carson. Wanted outlaw Dude Ramsey arrives and joins up with Tilden. First he saves the ranchers from Carson's trap and then exposes Pearson as Carson's informant and killer of Steve Warner.
Unable to legally capture and sell a herd of protected wild horses, corrupt rancher Rance Macgowan uses his trained killer horse, Volcano, to substitute for the real leader of the herd and cause havoc and death among the ranches. With the government about to drop the restrictions on rounding up the herd, the Three Mesquiteers find themselves in the middle of the controversy after their friend, Sheriff Miller is killed by Volcano.
The Louisiana Purchase is imminent and Gilmore is smuggling guns into St. Louis so his men can make him Governor of the new Louisiana Territory. But John Colfax fights to defeat Gilmore.
Hoppy goes undercover as an outlaw (which permits him, for once, to drink and be mean to children) to track down a bunch of outlaws operating along the border. Loco, the head bad guy, deflects suspicion from himself by pretending to be a moron.
The Transcontinental Broadcasting Company sends a sound truck and equipment to a ranch to obtain an audition from "Santa Fe" Evans and his musical cowboys (Oscar Gahan, Lloyd Perryman, Robert "Curley" Hoag, Rudy Sooter and Sherry Tansey.) Carver, arch enemy of Evans and a rival for the love of Carol Sheldon, fails in an attempt to spoil the audition. Carver frames Mr. Sheldon and Carol's brother Buddy on a charge, by Al Jensen, of receiving cattle stolen from him by Evans. Carver blames Evans for all of the Sheldon's troubles and, what with one thing or another, it looks like Evans and his cowhands will miss the big broadcast.
Brett runs a protection racket for an unknown boss. When Jeff Hayes arrives and opens a gambling den, they try to shut him down. Unlike the others who have given in, he plans to fight back.
Director Leslie Selander exhibits the sure-handed expertise that would endear him to latter-day western cultists in his 1937 formula western Sandflow. Buck Jones plays the son of a crooked land dealer. Seeking redemption, Jones rides through the west to compensate every rancher who was cheated by his dad.
A lawman poses as an outlaw, steals $10,000 from a cattle thief, then promises to return the money if he can join the gang--while finding a way to expose them.