In order to make ends meet and to stop a local, homeless teenager from becoming a juvenile delinquent, Hetty Wainthropp, a sprightly, intelligent pensioner looking for a new challenge, decides to become a private investigator much to the disgust and disbelief of her lazy husband. Once she has made up her mind she becomes an unstoppable force and, led by Hetty, the three set forth to investigate crimes of less interest to the local police force in and around their little village in the beautiful Lancashire countryside.