"The Grail of Montségur": At the end of the 12th Century, the Archon Reka uses her influence over the Pope to extend her power over the whole of Christianity. She subverts the Holy Inquisition with a secret aim of seizing the Grail and using the lost runestone of Dyo to gain dominion over her brother. But Erlin and Aker join forces with the Holy Roman Empire of Frederic II, determined to counter her plans!