Charley Wyckham and Jack Chesney pressure fellow student Fancourt Babberly to pose as Charley's Brazilian Aunt Donna Lucia. Their purpose is to have a chaperone for their amorous visits with Amy and Kitty, niece and ward of crusty Stephen Spettigue. Complications begin when Fancourt, in drag, becomes the love object of old Spettigue and Sir Francis Chesney.