The Butterworth family attorney Gaspar Le Sage, and a suitor for the hand of Eleanor Butterworth, persuades a beautiful Eurasian adventuress, Annabelle Wu, to help him steal the official plans for the coastal defense of California from Eleanor's brother, Lieutenant Butterworth. Annabelle gets the susceptible lieutenant drunk at a roadhouse, steals his keys, and gets the plans. Blame for the theft is placed on British secret service agent Lord Chumley, engaged to Eleanor, who immediately sets out to clear his own name and save the family honor. He prevents young Butterworth from killing himself, recovers the documents, and saves Eleanor, who has been abducted, in desperation, by Le Sage.