Roy Rogers (Roy Rogers), Frog Millhouse (Smiley Burnette), Gabby Whittaker (George 'Gabby' Hayes) and the Sons of the Pioneers (Sons of the Pioneers) undertake to protect the ranchers of Cherokee City from unjust charges levied against them for transporting their cattle to the stock yards of the packing houses. Trucking executive Ross Lambert (Edmund MacDonald) doubles his rates and Roy decides to try and convince old Colonel Silas Popen (Walter Catlett) to run his riverboat as far as Cherokee City and transport the cattle that way. Roy and his friends plan a "western" welcome for Popen and his daughter Mary Lou (Ruth Terry), but James Barabee (Paul Harvey, head of the cattleman's association, sends Roy a wire warning him that Popen hates and fears anything smacking of the "wild west.