Lady Windermere suspects that her husband may be having an affair with another woman. She confronts her husband but he instead invites the other woman, Mrs Erlynne, to her birthday ball. Angered by her husband's unfaithfulness, Lady Windermere leaves him for another lover. Mrs Erlynne follows Lady Windermere and attempts to persuade her to return to her husband. Mrs Erlynne ends up sacrificing herself and her reputation in order to save Lady Windermere's marriage. Her reasons are revealed in due course ...