A mysterious cosmic force-the "Ring of Fire"-has hurled thetown of Grantville from 20th century West Virginia back to 17th century Europe,and into the heart of the Thirty Years War. With their seemingly magicaltechnology, and their radical ideas of freedom and justice, the time-lost WestVirginians have allied with Gustavus Adolphus, King of Sweden, to form theConfederated Principalities of Europe, changing the course of history-in waysboth small and large.