In order to make ends meet, and to stop a local teenage runaway from becoming a juvenile delinquent, Hetty Wainthropp, a sprightly and intelligent 60-year-old pensioner looking for a new challenge, decides to become a private investigator much to the chagrin of her unemployed husband. Once she makes 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.