Seers of Verde - Williams Myron L

Marauders from a renegade planet attack an Earth colony ship forcing landing parties to split into two groups in a desperate attempt to escape. The attackers are killed but the colonists pay a terrible price. Their vessels are destroyed stranding them without their technology on either side of an imposing mountain range on the planet Verde Grande. 

Descendants of a mysterious Seer now protect their people but become the bane of the hunter society on the other side of the mountain. For two centuries all attempts to scale the mountain are thwarted by the powerful Seers who want to preserve their religion and way of life no matter the cost.

One day, a party of hunters sets out to climb the mountain. To their dismay, the Seers cannot control a strange unreachable young woman, who finds the passage to their protected valley. The reunion triggers a decades-long conflict between the Seers and the children of the “lost ones”—a struggle that forever changes the people of Verde Grande.