This historical novel is set in the Scottish Borders during the reign of Robert II, King of Scots (1371-1390). The story features the English Sir Philip Musgrave who captures Roxburgh castle and is committed to hold it for a specified period to satisfy his mistress Lady Jane Howard. James, Earl of Douglas, takes up a challenge by Robert's daughter Princess Margaret to recapture it within the same period. Sir Walter Scott of Rankleburn assists Douglas indirectly by harassing the English supply chain, to his own advantage. On the other hand, both Jane and Margaret assume male disguise in order to keep an eye on their respective lovers...