In Grubb’s Alley a beggar girl finds a ring in a handkerchief, on which is embroidered the word “Help.” She is arrested on the suspicion of having stolen the ring. At headquarters she begs the inspector to send for Miss Margaret Kent, a woman detective, who had befriended her. Miss Kent receives the message while glancing over the police report of one Steve Bright, forger, kidnapper and blackmailer. The only clue that the police have of him is a thumb print. This interests Miss Kent and upon leaving to go to aid the girl, she carries the thumb print with her. She succeeds in obtaining the girl’s release and suspecting something strange in the girl, disguises herself in the girl’s clothing and visits Grubb’s Alley. Here she sees two men enter a house in a suspicious manner. With the aid of Joe Miller, another detective, and disguised as Italians, with an organ and monkey, they await further developments. Shortly, the two men reappear and leave the house in charge of a nurse. While Miller is engaging the nurse’s attention, Miss Kent gives the monkey a pencil and note and sends him up the water pipe into the room above the spot where the handkerchief and note were found. An old lady receives the message that help is near and returns the following note, “Was drugged in New York. Don’t know where I am. To get control of my fortune am being driven insane by my nephew and others. Ann Harper.” Both Miss Kent and Miller leave the alley, but return disguised as two old beggars. They see a young man leave the house and rightly guess him to be the nephew of the old lady. Miller shadows him, but realizing that he is being followed, he rushes pell-mell into the house, where his fellow criminals are in concealment. Explaining the cause of his fear, one of the criminals formulates a plan by which they overpower Miller, drag him into the house, gag him and bind him with his own handcuffs. Then they send a note to the nurse instructing her to use the greatest precaution, and that at dusk they are going to remove the old lady. Miss Kent intercepts the note, and gives the messenger boy to deliver in place of it one that advises the nurse to follow the boy. She obeys and is led to a house that Miss Kent uses as her base of operations. Here she is overpowered and the key taken away from her. The old lady is released and instructed to await at police headquarters. Assuming the disguise of the old lady and simulating madness, Miss Kent is taken to the crook’s rendezvous, where she releases her assistant. The criminals are rounded up and taken to headquarters. Miss Kent notices that the leader keeps his hands carefully gloved and requests the man’s thumb print. This obtained, she compares it with the copy in her possession and her suspicion is confirmed. Thereupon she introduces to the officers the famous and elusive Steve Bright.