Neolithic man Kelab proudly presides over his tribe, which includes his wife Kisis and son. He is an imposing physical presence and frequently leaves camp to hunt. During one of these sorties, sadistic rival Krant and two accomplices enter the camp, rape and murder Kisis, and kill everyone else in plain sight. When Kelab senses the horrifying threat, he races back to his camp but arrives too late to save anyone except for a mewling baby. The tribal leader vows revenge.
I love this!