Space-age technology is pitted against medieval superstition and treachery in this wild and wacky comedy-fantasy. Astronaut Tom Trimble (Dennis Dugan) and his robot companion are unexpectedly hurled backward in time during a routine space flight and end up prisoners at the Court of King Arthur in sixth-century England. Adding to Tom's plight is his discovery of a sinister plot to overthrow the King, with the outcome resting on the flash-and-dazzle of the equipment at hand — from the 20th century!