Victorian-era Oxford students Charley Wykeham and Jack Chesney recruit their wealthy playboy friend, Lord Fancourt Babberly, to impersonate Charley's Brazilian aunt, Donna Lucia, to chaperone a double date the pair have planned. But unbeknownst to the trio, Jack's father happens to be after Donna Lucia's fortune, and the real Donna Lucia  has come to town incognito to check up on her nephew.