Wheel of Stars — Andre Norton

When Gwennan Daggert meets Tor Lyle--a tall, demanding man of ancient family--she enters an underworld of hellish nightmares and beautiful dreams.

She can see but she cannot forestall what is to come, for she is caught in an unbreakable cycle of doom, a struggle between good and evil older than Earth.

Gwennan and Tor hold the keys that unlock the future, but first they must face and conquer the forces bent on destroying those who will inherit the Earth.