Casting a skeptical eye on her husband's paltry pension, 60-year-old Lancashire housewife Hetty Wainthropp (Patricia Routledge) starts her own detective agency, relying on her native cleverness and the assistance of a homeless teen (Dominic Monaghan). Despite their low-budget operation, the two sleuths prove remarkably adept at solving an impressive range of mysteries that involve everything from missing persons to murders, mobsters and arson.