Astronauts Mac McKenzie (Frank Aletter) and Hector Canfield (Jack Mullaney) travel faster than the speed of light, resulting in being sent back in time to prehistoric days where they have to adjust to living with a cave-dwelling family led by Shag/Shad (Imogene Coca) and Gronk (Joe E. Ross).

Tribe Chief Boss (Cliff Norton) and his right-hand man Clon (Mike Mazurki) were always suspicious of the astronauts.

Boss and Clon make their final appearances in this episode, which also introduces two new supporting characters who remained with the show: Alan DeWitt as Mr. Tyler, manager of the apartment building where Mac and Hector live, and Frank Wilcox as General Morley, their commanding officer.

The prehistoric family begins adjusting to life in the 1960s, reacting to the unfamiliar surroundings and setting up a home in 20th-century Los Angeles.

According to Pat Cardi, who played Greer, CBS considered reversing their cancellation decision after ratings improved during summer reruns; however, Imogene Coca and Joe E. Ross had already committed to other projects, officially ending the series.