In the 1840s, Ramsey MacKay, the driver for the struggling Wells Fargo mail and freight company, will secure an important contract if he delivers fresh oysters to Buffalo from New York City. When he rescues Justine Pryor and her mother, who are stranded in a broken wagon on his route, he doesn't let them slow him down and gives the ladies an exhilirating ride into Buffalo. He arrives in time to obtain the contract and is then sent by company president Henry Wells to St. Louis to establish a branch office.

When Rocklin arrives in a western town he finds that the rancher who hired him as a foreman has been murdered. He is out to solve the murder and thwart the scheming to take the ranch from its rightful owner.

Having served a prison sentence for robbery, Pete Carver decides to go back for the hidden loot. But someone is on his trail.