Jim and Jill Tomkins are brought to the year 26930 and duplicates sent to their time to gather historical information lost in an atomic war. While in the future, the couple manages to help defeat a strange indestructible creature with their knowledge of Mark Twain's novel "A Connecticut Yankee in King Arthur's Court."
A simple piece of rope on exhibit was once used by an escape artist from Earth to rescue the kidnapped queen of the planet Baloran in time to save both planets from war.