The Commissioner of Police at Gottenberg, Messenia, is informed that a treaty is about to be completed between the two neighboring states, Keltia and Slavonia, which is in opposition to the interests of Gottenberg. Protea, a notorious adventuress, is commissioned to secure a copy of the document. Before accepting the commission, Protea asks for the assistance of a prisoner known as "The Eel." The prisoner is released and he and Protea set out on their mission. The Slavonic ambassador at Gottenberg, learning that Messenia is endeavoring to get a copy of the treaty, sends his secretary. Viscount Osthansen, to apprise the government of Keltia of the intended robbery. At the railway station Protea recognizes the Viscount and succeeds in ingratiating herself into his good graces while her accomplice appropriates his keys. The two spies later go to the Viscount's apartments, take his credentials and place in his valise articles subject to tariff. Unable to prove his identity to the custom officers he is arrested as a smuggler. In Keltia the two spies make their way to the Foreign Office, and as they are about to enter the minister's room the night watchman frustrates their plan. On the report of the watchman the treaty is placed in the safe for greater keeping. Later that day Protea, in the guise of an aged person, calls upon the minister. A large box is received from the Viceroy of Numidie. The minister is quickly chloroformed by Protea and with the aid of her confederate he is placed in the box. At the point of a pistol a young officer is compelled to relinquish his clothes, which are quickly donned by the adventuress. As she is about to take a mandate to the secretary, ostensibly from the minister, the chloroformed official recovers from the effects of the drug and again the plan of the spies is frustrated. It is only by the display of stratagem that the spies make their escape. The next diabolical plot worked out by the two spies finds Protea as the leader of the ladies' orchestra at a ball given by the minister of Keltia at the Foreign Office and her confederate as a man servant. The Viscount arrives and recognizes the leader of the orchestra as the astute spy. He hurriedly acquaints the minister of her presence. Protea realizes that she has been recognized and as she is conferring with her accomplice the new ambassador for Albania and his wife arrive. The wife bears a striking resemblance to Protea. As the ambassador and his wife are passing through the ante rooms they are pounced upon, bound and gagged by the spies, who proceed to array themselves in the clothes of their captives. They then proceed to the ballroom, where they are welcomingly received as the new ambassador and his wife, nobody penetrating their disguise. Shortly thereafter Protea feigns illness and as she had presaged she and her confederate ambassador are led into the minister's room where they find the document. In order to affect their escape they set the room on fire. The firemen arrive and a moment later the two spies appear as firemen, recognized by none. After the pandemonium has subsided the loss of the treaty is discovered by the minister and Ambassador Osthansen. The official institutes a search and a few days later the spies are captured in their home; but being ready for such an emergency they soon escape through the floor, which carries a secret passage. In order to cross the frontier unrecognized, Protea acquires some stock of a traveling menagerie and with her accomplice effectually disguised as a man-monkey, stop at an inn near the border of the frontier. Perceiving that her disguise has been penetrated by the proprietor she places the treaty in the care of the lioness Sadie, who keeps the police at bay. By the careful manipulation of a lever Protea sends the authorities and the innkeeper in a heap into the cellar. Securing the treaty Protea escapes into the forest while "The Eel" conceals himself in a tree. Her pursuers, who have been following her in an automobile being unable to navigate in the woods with the car, decide upon another plan to circumvent the daring spy from reaching her destination. They set the bridge on fire, which is the only means of reaching the desired location. Undaunted Protea leaps over a precipitous incline and lands safely on the other side of the water, where she rejoins her accomplice. There they array themselves in the dress of peasants and are later entrusted with the baggage of two officials who had come to inspect the guard on the frontier. Taking possession of the official's uniforms they pass the frontier unchallenged. The next day Protea hands the Commissioner of Police the much-desired treaty.