In Cologne Cathedral, during a holiday service, a mass killing occurs: all parishioners die in a horrifying death. Perpetrators dressed in monk’s robes steal a priceless relic kept in the cathedral since the 12th century—the bones of the biblical Magi. A team of special agents from the secret organization “Sigma,” led by Gray Pierce, is sent from Washington to investigate the crime. Together with Vatican scholars, the group manages to establish that the killings and the theft involve the Imperial Order of the Dragon—an underground brotherhood of alchemists whose roots go back centuries.