The term "Castle Dangerous" was applied to the feudal home of the Scotch Douglases, because of the many fierce fights for its possession which raged between the English and the Scotch lords, during the struggle of Kobert Bruce against King Edward I. Sir James Douglas, popularly called the Black Douglas, chief supporter of Bruce, has sworn that Douglas Castle shall not remain in the hands of the English. More than one English lord has attempted to hold it against attack or trickery, but in every case has come to a violent end. At last Lady Augusta de Berkely promises her hand and large estates to Sir John de Walton on condition that he hold the "Dangerous Castle" for a year and a day. He accepts the task and is made governor of the stronghold; but as the months slowly go by, Lady Augusta is overcome by misgivings and resolves to go to the castle and shorten the probation. Disguising herself as a youth, she goes in company of her father's minstrel Bertram as his son. They meet the deputy governor, De Valence, who agrees that the supposed boy shall be left at the convent of St. Bride's, near by, until formal permission to enter the castle has been secured, while the minstrel obtains entrance upon pretext of examining ancient songs ...