When Colonel Edward Ryan, D.S.O, M.F.H, changes his sex as a result of taking some horse pills, it has confusing repercussions. His son David is about to be engaged to Sandra Bendle, an American, and his daughter, Rosemary, is likewise involved with Tommy Devon. Before the Bendles arrive, the family decide father must pose as 'Aunt Edwina'. This works quite well until Edwina finds himself fending off Joseph P Bendel's advances with a sword. The engagement announced, Sandra, David and mother leave for New York. In her absence, the Press get hold of the story. Finally, the Colonel's bizarre predicament is solved in a still more bizarre way when his wife returns. For she has turned into a very handsome Uncle Cecil.