Speed Sullivan and his son Swifty are traveling salesmen who are very good at what they do but aren't entirely honest. Their main business seems to be taking deposits on lightning rods, that will never get delivered, and selling their homemade tonic which is made up mostly of booze. The Watson brothers are on their trail for what the magic elixir did to their father so both Sullivans are keeping one eye over their shoulder. When Swifty thinks he's found a piece of gold amongst Mark's collection of arrowheads and the like, Speed tries to make a deal to the mineral rights for the McCain ranch. There's something far more serious to deal with however when the Watsons catch up to Swifty and think Mark is the other swindler.
—garykmcd