Interweaves the stories of a twelfth-century French monk, an agnostic scholar searching for his Jewish wife in 1939 Berlin, and a group of radical Muslims in contemporary Frankfurt to explain the possible hidden origins of the religious and political fanaticism and intolerance within Christian Europe that began with the brutal subjugation of the Cathers and continued in various forms, from centuries of the Catholic Inquisition to the Nazi exterminations and today's violent conflict between East and the West.