Passing themselves off as wealthy business owners, brother-and-sister swindlers Tobias and April Horn (Robert Hogan, Marj Dusay) hoodwink the Cartwrights into helping them rob the Virginia City bank. Humiliated at being taken in by the siblings, and angry that his father was wounded in the robbery, Joe Cartwright rides into the desert in pursuit of the Horns-only to be outmaneuvered every inch of the way by the crooks' partner in crime, former army scout John Spain (Anthony Zerbe). "A Ride in the Sun" was written by John Hawkins and Peter Germano. The episode was originally shown on May 11, 1969, bringing Bonanza's tenth TV season to a close.
by Hal Erickson synopsis