Queens of Mystery follows the adventures of three crime-writing sisters Beth (Sarah Woodward, Endeavour), Cat (Julie Graham, Bletchley Circle) and Jane Stone (Siobhan Redmond, Taggart), and their 28-year-old niece Detective Sergeant Matilda Stone (Olivia Vinall, Apple Tree Yard). Using their knowledge of crime both real world and fictional together they solve murders in the picturesque English town of Wildemarsh. But no matter how many cases they are able to crack, the unsolved mystery that haunts all the characters is that of Matilda's mother's disappearance twenty-five years ago.