Michael Xabra, an anarchist, has been condemned to death for a dynamiting outrage in which four people perished. The Red Brotherhood, an anarchist society, the leader of which is Ferrand Boissevan, the keeper of a curio shop and an opium smuggler, have determined that if Xabra is executed they will spread germs of the bubonic plague throughout New York. Rose Lee, secretary to the Governor of New York, goes to Chinatown for her weekly supply of opium, but is unable to procure her supply due to new laws. During her days as a free-lance stenographer, Rose had done some work for Boissevan. He was greatly attracted to her, but she had repulsed him. He sees her in Chinatown, and promises to give her opium, on the condition that she report daily what the Governor intends doing about the case of Xabra. She consents. Carson Huntley sees Rose slink into the curio shop. Following he hides behind a curtain, hears of the plot discussed by Boissevan and his accomplice, Giovanni. Huntley telegraphs to Yorke Norroy that the Red Brotherhood is to be called together. He advises Norroy to disguise as a Russian and go to the meeting of the anarchists under the name of Jacobus of Wilmington. Norroy is on his way to New York. Huntley learns that a test tube in the possession of Boissevan contains the culture of the bubonic plague and that it is to be thrown into the New York City reservoir. Yorke Norroy arrives. He goes to the Governor’s office disguised as a Russian and puts Rose through a test to find out if she is one of the conspirators. Discovering that she is ignorant of the plot, he unfolds his plan to prevent the disaster. Realizing that her life has never been of any use to any one, she declares that she is glad to be of service. Norroy instructs her to get Boissevan to her rooms and there manage to break the test tube. He will prevent the spread of the germs by a strong chemical, which will destroy himself as well as the girl and Boissevan, for it will burn the whole house. Rose entices Boissevan to her house and there gets him into a large closet which has a spring lock. Deciding that two lives will be sufficient sacrifice, she follows him into the closet and hurls the lamp at him. The flames catch the clothes hanging about, and soon the forms of the girl and man are seen still struggling. Norroy rushes into the room too late to save Rose, although he makes so great an effort to do so, that he is finally carried unconscious by Huntley from the burning house.