Chip Brown, a retired diplomat, is living in the family manse in Montrose, Pennsylvania when he receives a note threatening death by fire unless he returns "the Yasna", a liturgical work written and used by the followers of Zoroaster long before the time of Christ. At the suggestion of retired Philadelphia homicide detective Kate Pierce, Chip digs into the history of his diplomatic career that was terminated abruptly when his wife, Henna, was uncovered as a Soviet spy. Follow Chip from quiet Montrose to Moscow as, in a race against time, he learns about Zoroastrianism, tries to find out why someone would be willing to kill to retrieve the Yasna, and uncovers things that Henna hid from him which ultimately put his life at risk.