On her first visit to her uncle’s estate, lively Antonia Thorpe is astonished to receive a proposal of marriage from a man she had never met before. Handsome debonair Fitzhugh Denholm is unabashedly relieved that for some reason his father’s plan to set him up in a marriage of convenience has failed. Only later through a coincidental encounter on the road to London does he finally understand that he proposed to the wrong Miss Thorpe, with Antonia’s cousin Rosamund actually to have been his intended.