David Gray's hunt for the famously incriminating Casket letters, belonging to Mary, Queen of Scots, takes him to Fast Castle in Berwickshire, to London on a delicate mission to King James, and to Paris to help woo Princess Henrietta Maria for Prince Charles. The author has also written Flowers of Chivalry, Columba, The Riven Realm, James, by the Grace of God and Rough Wooing.