The series starred Beverly Garland as Casey Jones, a female police officer who is often assigned to work undercover (hence becoming the "decoy" of the title). The cast changed each week with Garland the only main continuing character, although there were several recurring characters, mostly her commanding officer and immediate colleagues.
The series was inspired by Jack Webb's Dragnet, set in Los Angeles, California, and used a similar format to that series, with Jones portrayed as a serious, by-the-book, yet sympathetic cop with no personal life outside of her job. In the episode "The Sound of Tears", she reveals that the man she loved was a police officer who was shot and killed by the man he was sent to apprehend.
Decoy is of historical significance as the first American television series to focus on the work of a female police officer. The series also features early performances by such future stars as Larry Hagman and Peter Falk. Each episode is dedicated to the Bureau of Policewomen of the New York Police Department.
Many episodes focus on females being victims of crime, and most episodes ended with Garland breaking the fourth wall and speaking directly to the audience about the case just solved.