Prehistoric Rose saw the two males in front of her (who she don't remenber the names, but know they're familiar) and feeling the musk in the air, succumbed to the primitive instincts.
The naked cavewoman turned around presented her big hairy ass to the expecting cavemen. Kevin acted first and put his dick into Rose's waiting pussy which she moans pleasurably. The devolved couple then began to humping each other, while Jeff stands there, masturbating while watching his friends going on.
After a while the two cavemen came and lets a loud and ecstasic scream. Rose then catches the damaged Chronivac and smell it to know if she can eat it. She hears a grunt and turns to Jeff as if he's saying "box thing is important, made us", and said "we made more people with box thing", which she grunted accordlying.
Rose then hunched next to her mate Kevin and started to follow Jeff in turning more people into cavemen.