From the cover:
"When four moons rise the mystery and powers of the legendary world of Darkover are at their height. When the light of their conjunction bathes the world of the Bloody Sun, anything can happen, and Darkovan, Terran, and even the native chieri must all beware - for at such times the destinies of all who dwell in Keep, Tower, Guildhall, or town may forever be changed for good or ill."