In the early sixties two national treasures were the creative force behind one of British cinema's most successful franchises. But the Miss Marple movies were almost never made... Queen of Crime, Agatha Christie didn't want Margaret Rutherford to bring her fabled spinster to life. And Margaret Rutherford was mortified at the prospects of sullying her reputation with something as sordid as murder... This is the story of the real reason why the acting legend and "the funniest woman alive" didn't want to take on the role that made her celebrated across the world. Margaret and Agatha form an unlikely friendship filled with afternoon tea and gossip. Meanwhile Agatha turns detective herself and she's on a mission. She's determined to unearth Rutherford's tragic and shocking secret.