Lady Susan Vernon, a recently widowed and notoriously flirtatious woman, arrives at her in-laws' estate to wait out the colorful rumors about her dalliances circulating through polite society. With her daughter Frederica in tow, Lady Susan maneuvers through various societal interactions to secure advantageous marriages for both herself and her reluctant daughter. Utilizing her charm and intelligence, she engages in a series of romantic entanglements designed to ensure their financial futures.

Lady Susan's main focus becomes Reginald De Courcy, the brother of her sister-in-law. Despite initial resistance from Reginald's family, she successfully captivates him. However, her plans are complicated by the sudden arrival of Frederica, who has fled from school due to a planned union with the rich but foolish Sir James Martin. As Lady Susan manipulates those around her to achieve her goals, tensions rise and true intentions are revealed, setting the stage for dramatic confrontations and witty exchanges.