Night Caller (1973)

One hundred years after the third world war has occurred there are only two groups of people left: The savages whose minds have been destroyed by damaged genes passed on for a century and the intellectuals who totally live in their minds. However, survivor Nathan is an odd blend of the two opposing factions. Nathan takes revenge on the savages after they slaughter all the intellectuals. While in the middle of exacting his revenge Nathan receives a call from the long unused telephone lines from a mysterious female "night caller" who begs Nathan for help. Nathan must race against time to find the only remaining female member of his species before it's too late.