The main character is Mrs. Stevenson, is an old lady that can't get out of her bed. She is mad that her husband isn't home yet and calls his office to see where he is.
Is someone there?
She overhears a call where two men are planning a murder. She wants to stop the murderers before they commit the crime.
Ringing the Police department.
Mrs. Stevenson tries to get many people to help her stop the murder's plan. She tries to get the help of the police and phone operators, and she also tries to hire a nurse.
Police Department.Precinct 43. Duffy speaking
Sorry, wrong number.
When Mrs. Stevenson hears someone else in her house while she's on the phone with the hospital.
The man in her house kills her with the plan she overhead on the telephone earlier. The plan was about her.
The murderer has killed Mrs. Stevenson. He picks up the telephone and says, "Sorry, Wrong Number" to the person on the phone line.