Patricia Routledge stars as Hetty Wainthropp who gets her wings as a private investigator. Hetty, an unstoppable force of nature in a hat and sensible shoes, decides to track down the long-lost son of her best friend's husband. The sweet taste of success encourages her to search for missing persons on a professional basis. Only her aching feet slow her down as she searches for teenage runaways in the alleys and strip clubs of London. Hetty's husband, Robert, wants her at home, safe in the kitchen, but she never leaves a job unfinished, no matter how hard it becomes.