Holly Parker, the wife of a wealthy diplomat, is compromised by the accidental death of a man who has been romantically pursuing her. She is forced by her mother-in-law to assume a new identity in order to save the reputation of her husband and infant son. She wanders the world, trying to forget her heartbreak with the aid of alcohol and unsavory men. Eventually returning to the city of her downfall, she murders a blackmailer who threatens to expose her past. Amazingly, Holly is represented at her murder trial by her now adult son, who has become a public defender. In the hope of protecting her family, she refuses to reveal her real name and is known to the court as "Madame X".
