On a whim Viscount Medenham decides to take the place of a chauffeur who is unable to fulfill a booking to take an American heiress, Cynthia Vanrenen, and her chaperone on a tour of southern England. Shortly after beginning the tour Medenham discovers that the chaperone is scheming to trick Cynthia into a marriage with a French fortune hunter. He decides to thwart the pair and so begins an amusing game of cat and mouse with the conspirators.