Nancy, Bess, and George have become tap-dance enthusiasts. Nancy meets an eccentric retired actress, Miss Carter, who owns a large number of cats. Nancy attempts to solve a strange tapping sound at the woman's house. Miss Carter's finances are in a poor state, due mostly to the manipulations of a crook. Meanwhile, Nancy seeks to restore a former suitor of Miss Carter to favor. The story outline was completed by Edna Stratemeyer Squire, and was written by Mildred Wirt Benson, the series' primary ghostwriter. Mrs. Squire is noted to have unusual tastes in plot devices, and this is evident in the unusual action, chapter climaxes, and various other events in the book.