Aunt Bessie joins the planning committee for Manx National Heritage's new fundraiser, "Christmas at the Castle." Bessie is delighted that her friends, Marjorie Stevens and Mary Quayle, are also both on the committee. Carolyn Teare is a less welcome addition. When Carolyn insists on hiring Christopher Hart, an expensive designer, to "improve" everything, Bessie is even less happy. Aunt Bessie joins Mary and Marjorie in fighting against Mr. Hart's suggested changes to the beautifully decorated rooms. But when the man ends up dead, not liking his design style seems a pretty slim motive. Aunt Bessie joins forces with Inspector John Rockwell and his Douglas counterpart, Pete Corkill, as an act of vandalism and a second dead body threaten to get "Christmas at the Castle" cancelled altogether.