The Secretary of War receives a decided “jolt” when the daily papers assail the department for lack of zeal in running down the murderer of Colonel Allen, late commandant of the Presidio at Monterey, California. Kate Waters, of the Secret Service, is sent to the scene of the murder with a letter to Colonel Prentice, the successor of Colonel Green. In his household she assumes the role of housemaid in order to learn all she can from the troopers. Lieutenant Bronson flirts with her and she “jollies” him in turn. The commandant’s orderly is given a note written by “Pony” Collins, an officer who wounded Lieutenant Bronson on the night of the murder and later disappeared. Kate and the orderly have become friendly and, appreciating the fact that the orderly is the fountain-head of all post gossip, she “nurses” his regard for her. At her pouting demand, he shows her the note and from it she locates the whereabouts of the missing Collins. Accordingly she visits the underworld section of San Francisco in the guise of a cabaret singer. One night while she is singing a patriotic song, Collins enters under the influence of liquor. Seeing the flag in her hands, he comes to a military stand. Kate joins him at a table and then notices his West Point class ring. After a few drinks he “loosens up” and tells his story, relating to the dinner party at the colonel’s house; how he saw the colonel’s wife join Bronson in the gardens and make love to her; how he and the colonel joined them and how he ordered Bronson to leave with him; how he demanded that Bronson cease his attentions to Mrs. Allen; how they came to blows; how he was arrested and ordered to his quarters; how he saw from his window the colonel’s wife come from her home and meet Bronson, all dressed to go away; how the colonel came from the house after her and picked up a note she had dropped; how he, Collins, broke his arrest and ran to Mrs. Allen to prevent her going away; how he saw Bronson meet the colonel; how he saw their quarrel and how Bronson shot and killed the colonel; how he met Bronson and shot at him; how he broke from his captors and came to ‘Frisco. Kate persuades Collins to go back with her. She reports to the colonel, resumes her role of maid, meets Bronson, and by accidents gets the keys to his room. The same day she forces a confession from Mrs. Allen and that night “frisks” Bronson’s quarters and finds the incriminating note which he had written Mrs. Allen, bidding her meet him and run away. With this evidence she brings Collins to the commandant. Bronson is sent for and placed under arrest. Later Collins is reinstated and he and Kate become sweethearts.