The Forbidden Tower

"This is the novel of four who defied the powers of the matrix guardians--fanatics who protected those powers so that the planet of the ruddy sun might never fall beneath the influence of materialistic Terrans. The four who found themselves fused into a terrifying unity in that defiance were two men and two women. The men were Damon Ridenow, a Comyn of the ruling caste, and Andrew Carr, the Earthman who had won for himself the right of clan-entry. The women were Ellemir, betrothed of Damon, and Callista, who foreswore her vows to seek the love of the alien from the stars. All the forces of Ancient Darkover were to combine to resist this "unnatural" alliance."--Back cover.