A phone operator, Miss Moffatt, gets a call from some one involved in an emergency. She thinks it is a female being strangled and goes to the police station. Inspector Brackenreid does not believe her. She has a investigative nature and Brankenreid says she reported other things that did not happen.
The police find the body of a dead boy in an alley by a man who is later found dead. Miss Moffatt gives Officer Crabtree the telephone number where the emergency call came from. Murdoch goes to the house and finds blood by the phone but no body. The dead boy looks like he was strangled and Murdoch goes back to the house when the owner returns. The owner said nothing is missing. Murdoch notices a damaged phone cord, takes it to the coroner and finds out the boy was strangled by this phone cord.
This story is about adults using children to break into houses when people are on vacation. The boys are poor and are like homeless street kids. They get instructions by phone to find out what house they have to burglarize.
This part is unusual, Murdoch sets up wires at the police station to monitor the phone calls and also record the calls made from a certain phone number, in our time we we would call it "tapping" someone's phone.
During the mean time Brackenreid is preparing to run for Alderman and his goal is to make people like him.
The murders are solved in time for Brackenreid to look good. Miss Moffatt is like a Agatha Christy type and decides she want to start her own investigative agency.