Bonanza (1959)

S13E26 One Ace Too Many

While the Cartwrights are in Carson City, the unscrupulous land baron Bradley Meredith, played by Lorene Greene in a dual role, takes advantage of the situation. He impersonates Ben and concocts a devious plan to seize control of the Ponderosa by claiming that "Ben" is gravely ill and persuading friends to buy his shares.