The planet Melhandur is populated with humans of different nationalities living in a medieval lifestyle. Every several years, on demand, they are obligated to sacrifice a selection of their people to an alien spacecraft that comes to collect them, or risk being wiped out completely, as has happened to other settlements in the past.
William and the mortally wounded Larissa arrive on Melhandur, brought there while in search of help for Larissa. Years earlier their arrival had been foretold by an old acquaintance of William's, coupled with the warning that their arrival would herald the most dangerous of times for the people of Melhandur. Between the dangers posed by powerful warlocks and marauding Nordics, and the presence of a portal leading across space and time, lies the mystery of the origin of the Sapphirus Tempus.