Howard Duff guest-stars as Sam Clemens, who in the days before his fame and fortune as "Mark Twain" could be found working as a reporter on the Virginia City Enterprise. The Cartwrights come to Clemens' assistance when the young journalist endeavors to expose an illegal collusion between Judge Yerrington (John Litel) and a powerful railroad executive. Featured in the cast are Dorothy Green as Minnie andAnn Whitfield as Rosemary. Written by Harold Shumate and first broadcast October 10, 1959, "Enter Mark Twain" might prove an interesting comparison to the 1972 Bonanza episode "The 26th Grave," in which Sam Clemens is also a central character. ~ Hal Erickson, Rovi