Their eyes heavy with grief, Edith and Violet, dancers, return from the funeral of their sister, Grace. They find a letter marked, "To be opened after my burial," which encloses a photograph. This, the dead sister identifies as the man who has wronged her and through his falseness has brought her to her death. Her request is that her sisters seek him out and avenge her. Strangely enough, she omits to mention his name and address. Conjuring before them the image of the beloved departed, Edith and Violet swear to find the unknown and wreak their worst upon him. Assuming new names to aid their search, the sisters are engaged to dance in a music hall. Here comes Viscount Henry, and a party of friends. This count is peculiarly attracted by the mysterious masked sisters. He asks the manager to introduce him. Violet's beauty is the source of particular attraction. The other sister fears danger and recalls to her her sister's fate. This count persists, although a likeness to the dead Grace, to whom he once promised marriage, causes him uneasiness. Edith, calling upon the viscount to learn the purpose of his attentions, accidentally finds her late sister's portrait. Returning with the portrait of the viscount the sisters compare the one which the sister had enclosed in her last letter. They are identical. Edith reminds Violet of their oath of vengeance. It falls to Edith's lot to execute the oath. She goes to the viscount's house and confronts him with his guilt. He orders his servants to arrest her. She escapes. Keenly anxious, the other sister, Violet, comes to the house about this time. She is daunted by the onrush of the pursuers who are chasing her sister. Mistaking Violet for Edith, they pursue the former, and a stern and exciting chase it is. Edith, in the meantime, returns to the house, where she meets the Viscount, now unprotected by his servants. A shot from Edith's revolver, and a long fall down a secret passage ends his evil life.