Ervin Plummer-played by the estimable George Macready, who like his good friend Vincent Price was a man of culture and erudition who specialised in bad guy roles-is a grasping avaricious businessman with a hunger for gold.

Willis Newcomb and Bart Carroll head a gang engaged in smuggling wanted-American criminals back into the United States from Mexico. Operating from Sharperville, an oil town on the American side of the border, they transport their human cargo in oil drums loaded on trucks. Border Patrolman Tom Sharper intercepts one of the trucks but is overpowered and left for dead. Carroll, having already been paid for the job and not wanting any evidence to walk around, get caught and lead back to him, backs the human-cargo trucks to the edge of a cliff and sends the drums crashing to the boulder far below. Judge Cookie Bullfincher and Border Patrolman Roy Rogers conduct a search for the missing Tom, but the crooks have gone back for him and find him in a state of amnesia. They rob the bank and pin it on Tom. It is now up to Roy to clear his friend and also put an end to Carroll's human-smuggling racket.

Twenty years earlier Farrell killed his mining partner Andrews. Now Andrews daughter arrives to get her father's trust fund. Farrell having rustled Roy's cattle now takes her money from her Lawyer and lets her overhear false information of their next rustling job. With the posse at the wrong location, his men attack the cattle train and Roy on board find himself greatly outnumbered.

Jean Loring has her men illegally killing and selling game. Roy suspects her and gets himself invited to stay at her ranch. Investigating he finds the freezer where the slaughtered game are kept. But he is caught, tied up, and left to freeze.

On vacation at his ranch, western actor Roy quickly finds himself involved with a horse rustling operation and a boy ward of one of the rustlers, leading to the kidnapping of Roy's trick horse Trigger by the gang with a demand for ransom.

Mine owner William Sharon keeps having his gold shipments held up by a gang of bandits. Sharon hires banker Charles Crocker, who happens to have connections in the Central Pacific Railroad, to build a spur line from Virginia City to Carson City, so that the gold can be shipped by railroad. Silent Jeff Kincaid is the railroad engineer. However there is opposition to the railroad, chiefly from another mine owner, Big Jack Davis.

In Roy Rogers' Down Dakota Way, the deadly hoof-and-mouth disease has struck the herd owned by evil rancher H. T. McKenzie (Roy Barcroft). To avoid an expensive quarantine on his stock, McKenzie plans to murder the local veterinarian (Emmet Vogan) before the latter can report his findings to the government. Rogers manages to straighten out the situation by appealing to the sensibilities of the aunt (Elizabeth Risdon) of McKenzie's hotheaded hired assassin (Byron Barr). The film also bears several musical numbers from Roy, Dale Evans, and Foy Willing and the Riders of the Purple Sage.