86-year-old Irving Zisman is on a journey across America with the most unlikely companion: his 8 year-old grandson, Billy.

In the sixth film in the series, in February 1916, high school student Indy's plan of taking his girlfriend Nancy is sidetracked when a mysterious break-in, the theft of an electric motor, and rumors of German spies result in a mystery that only young Indy and Nancy can unravel. Indy and his father then head to the southwest to visit family in Albuquerque, where Junior is taken captive by Pancho Villa and his riders.