In PREHISTORIC WOMEN, the titular cavewomen are treated as slaves by the men in their tribe. Fed up with their situation, they rise up and flee, allowing them to enjoy their freedom in the wilderness.
Uh oh!
It seems they forgot the fact that without men, as odious as they are, the women will face certain extinction. Luckily, there's a male tribe nearby, allowing the females to conquer and enslave the poor saps. Not taking kindly to this, the he-men revolt, and the roles are reversed. Etc.
This is, as one might have guessed, an absurd movie. It's basically about the "battle of the sexes" 1950's style, with era-appropriate stereotypes and healthy doses of sheer nonsense. Unfortunately, none of it is all that interesting or entertaining.
On the positive side, we do learn the true origin of both fire and the use of levers...