Guilty of wartime treachery, Duke Mareno leaves a suicide note accusing his wife of infidelity. The duke's father, Prince Danieli, thereupon denounces the duchess, who flees to London and becomes a popular fortune-teller, known as Madame L'Enigme. When Richard Oak, whom the duchess knew in Italy, invites her to perform for a charity ball, he finally recognizes her and confesses his undying love. But the duchess does not respond and tries to keep her identity secret. Singer Mario Dorando also recognizes her and informs Prince Danieli. Duchess Mareno's anxiety mounts until her father-in-law finally appears with the news that the duke was actually killed by his gardener in revenge for a woman he had wronged. Her position in society restored, the Duchess Mareno accepts Richard.