After Rear Admiral Jeremy West is dismissed because plans entrusted to him for the country's security have disappeared, he collapses and is taken to a sanitarium. West's daughter Ruth overhears his secretary, Alfred Trimble, plot with a man named Wolvert, and tracks them to the Fifth Avenue address of Mrs. Marcia Vanderhold. Masquerading as her friend Betty, Ruth becomes a stenographer for the Associated War Charities, of which Mrs. Vanderhold is president. After Ruth's aunt hires Herbert Ross, a young detective, to find her, Ruth becomes Mrs. Vanderhold's personal secretary. When the previous secretary is found dead, Ruth refuses Herbert's offer of help, and accompanies Mrs. Vanderhold to her Long Island villa, where Trimble arrives with a man called "His Excellency." After Ruth learns that the plans are hidden in a wall safe, she chloroforms Wolvert and recovers them. When Trimble recognizes her, Ruth knocks a lamp over and shots flash in the darkness. Herbert turns the light on, and Ruth embraces him. The crooks are arrested, West is reinstated, and Ruth accepts Herbert's proposal.